nutrition manual fd spa 2012 changes

Trafford College Lifestyle Management

Nutrition Manual forNutrition Manual for Lifestyle ManagementLifestyle Management

ModuleModule

MMU FD in Spa ManagementMMU FD in Spa Management

Student Name __________________________

If found please return to Richard Campbell (Tutor) – RH2.07

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Table of ContentsTable of Contents

Page NumberPage Number

Introduction 3

Recommendations 4

Carbohydrates 9

Fibre 24

Fats 33

Protein 47

Vitamins & Minerals 54

Fluid Replacement 65

Anti-nutrients 69

Food Additives 71

Diets 76

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Introduction

Nutrition is the provision, to cells and organisms, of the materials necessary (in the form of food) to support life. Many common health problems can be prevented or alleviated with a healthy diet.

A poor diet can have an injurious impact on health, causing deficiency diseases such as scurvy; health-threatening conditions like obesity and common chronic systemic diseases as cardiovascular disease, diabetes, and osteoporosis.

There are six major classes of nutrients: carbohydrates, fats, minerals, protein, vitamins, and water.

These nutrient classes can be categorized as either macronutrients (needed in relatively large amounts) which consist of carbohydrates, fats, proteins and water or micronutrients (needed in smaller quantities) which consist of minerals and vitamins.

A balanced diet contains all the 6 nutrients plus fibre (the non digested carbohydrate) in the correct amounts.

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http://en.wikipedia.org/wiki/Carbohydrates


RECOMMENDATIONS - UK

In 1991, the United Kingdom Department of Health published the Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. This records Dietary Reference Values (DRV) which recommended nutritional intakes for the UK population. The DRVs can be divided into three types:

RNI - Reference Nutrient Intake (97.5% of the population's requirement is met) EAR - Estimated Average Requirement (50% of the population's requirement

is met) LRNI - Lower Recommended Nutritional Intake (2.5% of the population's

requirement is met)

RNI is not the same as RDA (Recommended Daily Allowance) or GDA, although they are often similar.

Current Recommendations

General advice is given for healthy people. The government recommends that healthy people should eat a diet which contains plenty of starch (rice, bread, pasta and potatoes). It also recommends that a person should eat at least 5 fruit or vegetable portions each day. Meat, fish, eggs and other protein-rich foods should be eaten in moderation. Dairy products should also be moderately consumed. Finally, salt, saturated fat and sugar should be eaten less.

This advice is summarised in the eat well plate.

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Note that exceptions to these rules include pregnant women and young children. Additionally, those who have little exposure to sunlight may need to take vitamin D supplementation.

Sources of Energy

The Dietary Reference Values (DRV) below are specified mainly for adults. They define the proportion of a person's total energy intake which should come from different components of food. These include fat and fatty acids, fibre, starch and sugars. Note that these values do not apply to children, and children younger than five with small appetites should not have such restrictions imposed.

Nutrient Average percentage of food energy

Saturated Fatty Acid Not more than 11%

Polyunsaturated Fatty Acid 6.5%

Monounsaturated Fatty Acid 13%

Trans fats Not more than 2%

Total Fat Not more than 35%

Non-milk intrinsic sugars Not more than 11%

Intrinsic milk sugars and starch 39%

Total Carbohydrate 50

Fibre as non-starch polysaccharide (g/day) 18 [not applicable to children under 5]

Salt

The guideline salt intake for adults is about 6 grams of salt (approximately one teaspoon). The Food Standards Agency estimate the average salt intake is about 8.6 grams/day (2008). A high salt diet is likely to increase the risk of high blood pressure, which is associated with an increased risk of heart attack and stroke.

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Age Target salt intake (grams per day)

0–6 months Less than 1 gram

7–12 months 1 gram

1–3 years 2 grams

4–6 years 3 grams

7–10 years 5 grams

11 years+ 6 grams

Extension to EU level

In recent times, Dietary Reference Values are under the interest of the European Food Safety Authority too, which intend to extend them at the EU level. EFSA is the equivalent of the Food and Drug Administration (FDA) in the USA, and acts as watchdog inside the European market in order to establish a common ground on food safety requirements and nutrition as well.

EFSA met in September 2009 with representative of the Member States in order to gain their views on fats, carbohydrates, fibres and water as well as Food-Based Dietary Guidelines. Furthermore EFSA is searching for comments (Open Consultation) by 15 October, in order to validate its assumptions on the need to have:

carbohydrates comprising 45% – 60% of the overall daily caloric intake fats being comprised among 20% / 35% of the overall caloric intake fibre needs: complying with 25 grams/day

EFSA considers that there are not sufficient data to set DRVs for sugars, and not systematic scientific substantiation linking diseases such as stroke or diabetes (DMT1 or DMT2) to an increased intake of sugars (glycemic load/glycemic index). In any case, there is much literature referring to this link, on journals with very high impact factor and statistically robust design and results

Many problems seem nowadays to derive from having integrated EU level DRV:

the presence of a previous EFSA opinion on Food Based Dietary Guidelines, aimed at stressing the need of having only country-based guidelines, against the WHO hypothesis. This is due to very different food patterns, for EFSA, inside Europe.

the presence of private scheme such as GDA (Guideilnes on Daily Amounts), referring on the same subject (calories from nutrient groups) but casting shadow on the effectiveness of DRVs as public authorities' scheme.

RECOMMENDATIONS – US & CANADA of 113


The Dietary Reference Intake (DRI) is a system of nutrition recommendations from the Institute of Medicine (IOM) of the U.S. National Academy of Sciences. The DRI system is used by both the United States and Canada and is intended for the general public and health professionals. Applications include:

Composition of diets for schools, prisons, hospitals or nursing homes Industries developing new food stuffs Healthcare policy makers and public health officials

The DRI was introduced in 1997 in order to broaden the existing guidelines known as Recommended Dietary Allowances (RDAs). The DRI values are not currently used in nutrition labeling, where the older Reference Daily Intakes are still used.

History

The Recommended Dietary Allowance (RDA) was developed during World War II by Lydia J. Roberts, Hazel Stiebeling, and Helen S. Mitchell, all part of a committee established by the United States National Academy of Sciences in order to investigate issues of nutrition that might "affect national defense" (Nestle, 35). The committee was renamed the Food and Nutrition Board in 1941, after which they began to deliberate on a set of recommendations of a standard daily allowance for each type of nutrient. The standards would be used for nutrition recommendations for the armed forces, for civilians, and for overseas population who might need food relief. Roberts, Stiebeling, and Mitchell surveyed all available data, created a tentative set of allowances for "energy and eight nutrients", and submitted them to experts for review (Nestle, 35). The final set of guidelines, called RDAs for Recommended Dietary Allowances, were accepted in 1941. The allowances were meant to provide superior nutrition for civilians and military personnel, so they included a "margin of safety." Because of food rationing during the war, the food guides created by government agencies to direct citizens' nutritional intake also took food availability into account.

The Food and Nutrition Board subsequently revised the RDAs every five to ten years. In the early 1950s, United States Department of Agriculture nutritionists made a new set of guidelines that also included the number of servings of each food group in order to make it easier for people to receive their RDAs of each nutrient.

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Current recommendations

The current Dietary Reference Intake recommendation is composed of:

Estimated Average Requirements (EAR), expected to satisfy the needs of 50% of the people in that age group based on a review of the scientific literature.

Recommended Dietary Allowances (RDA), the daily dietary intake level of a nutrient considered sufficient by the Food and Nutrition Board to meet the requirements of 97.5% of healthy individuals in each life-stage and gender group. It is calculated based on the EAR and is usually approximately 20% higher than the EAR.

Adequate Intake (AI), where no RDA has been established, but the amount established is somewhat less firmly believed to be adequate for everyone in the demographic group.

Tolerable upper intake levels (UL), to caution against excessive intake of nutrients (like vitamin A) that can be harmful in large amounts. This is the highest level of daily consumption that current data have shown to cause no side effects in humans when used indefinitely without medical supervision.

The RDA is used to determine the Recommended Daily Value (RDV) which is printed on food labels in the U.S. and Canada.

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CARBOHYDRATES

All living cells contain carbohydrates. In humans, plants provide the major source of carbohydrate in the diet.

Carbohydrates (sugars) are formed by combining the atoms carbon, hydrogen and oxygen.

Carbohydrate has the following chemical formulae- (CH2O)n, where n equals from 3 - 7 carbon atoms. For example glucose contains 6 carbon, 12 hydrogen, and 6 oxygen atoms, thus the chemical formula for glucose is C6H12O6. A distinguishing feature of carbohydrates is that there are usually 2 hydrogen atoms for every oxygen & carbon atom in each molecule.

Fructose and galactose are two other sugars that have the same chemical formula as glucose (i.e. C6H12O6), however the arrangement of the atoms within fructose and galactose is slightly different making each sugar unique.

There are four categories of carbohydrates (sugars):

Monosaccharides single sugars, mono = one Simple Sugars

Disaccharides 2 sugars linked, di = two

Oligosaccharides 3 - 9 sugars, oligo = few

Polysaccharides 10 - 1000's of sugars, poly = many

Complex Sugars

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Monosaccharides

Monosaccharides are the basic units of carbohydrates. In nature, more than 200 monosaccharides exist.

In humans glucose, galactose and fructose are the nutritionally important monosaccharides.

Glucose

Glucose (also called dextrose) can:

occur naturally in food (eg onions and beetroot) be formed by digesting more complex carbohydrates be formed by the liver from specific amino acids

Glucose can be:

used by cells to provide a source of energy stored as glycogen in the liver and muscles (for future use) the liver can also transform excess glucose into fat, which is then stored in

fat tissue (adipose tissue)

Before glucose can be utilised as an energy source for body cells it must pass through each cell membrane. The speed at which this can occur is greatly increased if the hormone insulin is present in the blood stream.

Once glucose enters a cell it is immediately combined with a phosphate atom. This prevents the glucose molecule from moving back out of the cell into the blood stream,

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and enables the cell to hold onto glucose until it is required as a source of energy.

Some cells such as those found in the liver, kidneys and intestines possess specialised enzymes, which allow the attached phosphate atom to be removed. Once phosphate is removed, it is possible for glucose to leave the cell and move back into the blood stream.

Glucose Storage

If glucose is not required as an immediate source of energy, it is combined with lots of other glucose molecules to form glycogen. The body's cells are stimulated to make glycogen when the hormone insulin is released into the blood stream.

Glycogen can be stored in the liver and the skeletal muscles. A well nourished 80kg person is able to store approximately 500g of carbohydrate. The biggest reserve of carbohydrate (approximately 400g) exists as muscle glycogen, 90 - 110g as liver glycogen, and the rest exists as glucose circulating in the blood stream. Each gram of carbohydrate (either glycogen or glucose) contains approximately 4 calories of energy (3.8Kcal/g), thus an average person stores between 1500 - 2000 calories of carbohydrate - enough to power a 20 mile run at high intensity.

(Source: McKardle, Katch & Katch, 1999)

Glucose provides both the brain and the muscles of the body with an essential form of energy. Unlike muscle cells, brain cells are

• unable to store glucose• unable to burn fat as an additional fuel source.

The brain must receive a constant supply of glucose from the blood stream if it is to continue to function at an optimal level. Any individual who has low levels of glucose in their blood stream will experience fatigue in their muscles and a gradual deterioration in mental functioning (concentration, determination etc).

Thus, it is crucial that blood glucose levels are maintained for the following reasons:

to keep the brain functioning to supply energy to the body's cells- replacing used glycogen stores to regulate the appetite

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Disaccharides

There are 3 main disaccharides: sucrose, lactose and maltose.

SucroseSucrose, obtained from sugar cane, consists of one unit of glucose and one unit of fructose.

LactoseLactose is found in milk, it consists of one unit of glucose and one unit of galactose.

MaltoseMaltose is known as malt sugar, it is obtained from germinated barley.

Polysaccharides - made up of many (poly) monosaccharide units.

The main polysaccharide in the human diet is starch which is formed from many glucose units. Starch is the food reserve of cereals, vegetables and pluses.

Which Foods Contain Carbohydrate?

Some good sources of carbohydrate include:

beansbread cereals dried and fresh fruit potatoes and other root vegetables pancakespastarice

Other foods such as cakes, crisps, pastry and chocolate also contain significant amounts of carbohydrate however; these foods are also high in saturated fats and low in vitamins and minerals, making them a poor choice nutritionally.

Which Type of Carbohydrate Food Should You Choose?

All carbohydrate foods are broken down into glucose and then stored as glycogen in the liver and muscles.

When choosing which carbohydrate foods are best there are 3 main things to consider:

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1. The nutritional content of the food

Those foods that are high in complex carbohydrates and those that have naturally occurring sugars ie fruit are more nutritious and generally lower in fat.

2. How bulky the food is (i.e. how much fibre the food contains).

Foods that are high in complex carbohydrates are often high in fibre and can be very filling. Whilst the average person in the population is encouraged to consume more fibre it is important to remember that foods containing a lot of fibre can sometimes be difficult to eat if you have a high energy requirement. For example if you were an athlete who needed 4000 kcal each day you would need approximately 600g of carbohydrate (this would be the equivalent of 20 potatoes or 37 slices of bread). Most Athletes would find it difficult to consume this quantity of food in between their training sessions. Thus, for those individuals who have a high calorie requirement it is often necessary to top up carbohydrate intake with foods such as carbohydrate drinks or even biscuits as they are less bulky.

3. The glycaemic index.

Occasionally there is a need to consume foods that can be easily absorbed, for example, before, during and immediately after exercise. The glycaemic index is a way of measuring how quickly carbohydrate (glucose) can be absorbed and how quickly the levels of glucose in the blood then rise. A food with a high glycaemic index indicates that the carbohydrate within the food is easily absorbed by the body. Glucose has an index of 100.

One thing that confuses many people about the glycaemic index is that, the ability of a carbohydrate to be quickly absorbed once eaten does not depend on whether or, not it is a complex carbohydrate (ie along chain of sugars). Rate of absorption is affected by factors such as:

• the presence of fibre (soluble fibre slows down the absorption of glucose)

• the presence of other nutrients ie fat or protein• the type of starch• cooking or processing -cooking alters particle size and processing removes fibre.

All of the above factors can affect how quickly the carbohydrate can be absorbed.

The following table identifies the glycaemic index of some typical foods.

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The Adverse Effects of Sugar

ObesitySugar is easy to consume in large amounts, it is extremely difficult to consume the same number of calories of complex carbohydrates because the sheer bulk of the food would be so great. This would appear to be Nature’s way of helping us control our appetites.

HypertensionIn some individuals, a high sucrose intake produces an increase in blood pressure.

Elevation of blood fatsSucrose ingestion, like that of alcohol, markedly raises levels of certain blood fats, particularly the triglycerides, Sugar can also elevate cholesterol in some people.

Platelet StickinessBlood platelets are responsible for the clotting of blood, if over-active, this may result in an increased liability to blood clotting, which can cause a stroke or impaired circulation in the legs. Smokers are particularly at risk, taking sucrose has been found to increase blood platelet stickiness both in healthy volunteers and those with peripheral arterial disease.

Atherosclerosis and chromium deficiencySucrose increase losses in the urine of the essential trace mineral chromium. Low levels of chromium and associated with increased atherosclerosis (hardening of the arteries), coronary artery disease, elevated blood cholesterol levels and diabetes.

Diabetes mellitusDiabetes is not simply caused by eating too much sucrose, closely related to an excess calories intake from both carbohydrates and fat. Current dietary advice urges an increased intake of complex carbohydrates, high in fibre, from such sources as whole grains, lentils, beans, nuts and seeds, rather than the intake of glucose and sucrose. This can be helpful for diabetics who are experiencing a hypoglycaemic episode which can occur in both those on insulin and those receiving oral anti-diabetic drugs.

Gastrointestinal DiseasePeople with Chrohn’s disease have been found to have a higher sucrose intake that their healthy counterparts. There may be a link with carbohydrate intake and colitis. Low-sugar high-fibre diets have been recommended in the treatment of diverticular disease and, with the use of unprocessed bran, have been found to be highly effective.

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GallstonesResearch at Bristol Royal Infirmary has shown that a diet providing the average amount of sucrose consume in the UK produces an increased concentration of cholesterol in bile and therefore, an increased risk of gallstones.

Tooth DecayTooth decay depends not only on the amount of sugar eaten, but the frequency and type. Consumption of foods in which sugar is sticky or caramelized (and thus easily adheres to the teeth) is more likely to cause dental problems. Crisps are a particular problem in causing tooth decay.

Kidney DiseaseSome people appear to retain salt (and water along with it) when consuming a diet high in sucrose. In a weight reduction programme in which the intake of refined carbohydrate is cut dramatically, there is often a marked reduction in weight as a result of loss of body fluid. High sucrose consumption appears to have an adverse effect upon the metabolism of people who have kidney stones.

Resistance to InfectionSucrose has a rapid and dramatic adverse effect upon the ability of white blood cells to fight infection. In studies where students were given 24 ounces of a sucrose containing soft drink, there was a rapid rise in blood sugar within 45 minutes, at which time the ability of certain types of white blood cells to ingest and destroy foreign bacteria was significantly impaired. It is well known that diabetics, who have impaired glucose tolerance, are especially likely to get infections.

Behaviour and Mood ChangesA deficiency of vitamin B1 can occur in people who eat a diet high in refined carbohydrates. This can be a cause of, or aggravate, existing depression and anxiety. Vitamin B1 demands are increased by diets high in refined carbohydrates, and sugar such as sucrose contain none of the B vitamins that are necessary for their metabolism. Some children experience adverse reaction to sucrose in food.

Skin DiseasesMany people who have poor skin, or are susceptible to spots and pimples, improve by butting out sugar and refined carbohydrates (including ice cream, sweets and chocolate) from their diet.

Apart from the sugar you consciously add to drinks or food, sugar is also contained in many manufactured foods. Approximately 60% of the sugar consumed in the UK is taken in this way.

The National Advisory Committee on Nutrition Education recommended that the consumption of sucrose should be reduced to 20Kg per head per year.

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The recommendation is based on the amount of sugar available for consumption in the UK. Allowing for a certain percentage of wastage that is inevitable, this can be translated into the maximum number of teaspoons recommended per day per person.

The recommendation is not more than a total of 10 teaspoons a day (including all those added to tea and coffee). If you take less, so much the better. Below is a table listing the sugar content of popular foods:

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Simple Advice to Avoid Sugar

Beware fruit juices – they are notoriously high in sugar. Dilute them with water to reduce the sugar without sacrificing taste.

Look for artificial sweeteners (NutraSweet, saccharine, aspartame*), to give you the taste without the sugar. But do read labels carefully, because ‘low calories’ may not mean ‘sugar free’.

Check carbohydrates, while many products tell you how much of the carbohydrate content is from sugar (as opposed to starch), others don’t. However, virtually all of the carbohydrate in fruit drinks will be sugar, even when it’s not listed separately.

Forbidden fruit – one of the highest sugar-containing food groups is fruit and although natural plant sugars offer their won benefits, one way of reducing your sugar intake is to be selective about which fruit you eat. The worst culprits are dried, stewed and canned fruit, especially those in heavy syrup.

Fish and meat – the amount of sugar in fish and meat is negligible, which makes them good choice if you want to lower your sugar load, just be careful about sauces and condiments which can contain a lot of sugar.

Bread such as bagels, muffins, ordinary loaves, French sticks and crumpets are typically very low in sugars. Pastries cakes and biscuits, however, are generally not, so avoid them.

Cheese is high in fat but contains virtually no sugar. Watch out for spreads and processed cheese which do contain more sugar, as do fromage frais, yoghurts and sweetened creams.

Chocolate and sweets are the worst offenders. Try to limit them or choose smaller servings – a King size Mars Bar contains 24 cubes of sugar, compared with a Snack size Mars Bar, which has 10.

Drink diet carbonated drinks. A 500ml glass of cola contains 21 cubes of sugar, whereas a diet cola has none.

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* Aspartame has been found to be safe for human consumption by more than ninety countries worldwide, with FDA officials describing aspartame as "one of the most thoroughly tested and studied food additives the agency has ever approved" and its safety as "clear cut", but has been the subject of several controversies, hoaxes and health scares.

Problems with safety tests were found following the initial approval by the U.S. Food and Drug Administration (FDA) in 1974. Approval was rescinded the following year and after reviews and additional testing, final approval was granted in 1981. Allegations of conflicts of interest marred the FDA's approval of aspartame; question the quality of the initial research supporting its safety; The U.S. Government Accountability Office conducted reviews of the actions of involved officials in 1986 and the approval process in 1987; neither the allegations of conflict of interest nor problems in the final approval process were substantiated.

A widely circulated email hoax cited aspartame as the cause of numerous diseases. The Center for Disease Control investigated and was unable to find any significant epidemiological associations to serious risk or harm.

The weight of existing scientific evidence indicates that aspartame is safe at current levels of consumption as a non-nutritive sweetener. Reviews conducted by regulatory agencies decades after aspartame was first approved have supported its continued availability

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Carbohydrate and Exercise

Eating carbohydrate before exercise can help you to maintain higher blood sugar levels which may help delay fatigue - allowing you to train harder and for longer.

It is recommended that approximately 50g of carbohydrate should be consumed 5 - 30 minutes before exercising (this does not mean consume a meal). It is important to note that some individuals may not respond very well to this strategy, remember everyone is unique and it is often necessary to try different amounts of carbohydrate at different times.

Following exercise, you need to start re-fuelling as soon as possible. The body replaces its glycogen stores much faster during the first 2 hours following physical activity. Research has shown that during this period, the speed at which glucose is stored in the muscles as glycogen is vastly increased. Consequently, the sooner you replace any used glycogen stores (by eating plenty of foods high in carbohydrate) the quicker and more efficiently you will recover.

To ensure you refuel efficiently you need to consume a minimum of 50g of carbohydrate within the first 2 hours following exercise (preferably you should consume approximately 1g of carbohydrate per kg of bodyweight). You also need to continue to consume at least 50g of carbohydrate every 2 hours (i.e. eat frequently throughout the day). This is because glycogen storage is much slower if long gaps are left between eating. Remember also, if all you carbohydrate is eaten at just 1 or 2 meals each day there may be a possibility that some of it is converted into body fat.

Below is a list of suitable snacks, which would supply at least 50g of carbohydrate:

1 pint of isotonic sports drink 7 oz of cooked pasta

2-3 bananas 6 oz of cooked rice

1 banana sandwich 4-5 oatcakes

3 oz of dried fruit 2 oz of breakfast cereal with ½ pint of low fat milk

3 slices of bread 6 oz baked potato with 4oz of baked beans

7 rice cakes 1 bagel

Summary of Recommendations for Carbohydrates

1991 UK Department of Health Dietary Reference Values for Food Energy and Nutrients

Average Percentage of food Energy = 50%

National Advisory Committee on Nutrition Education

10 teaspoons of sugar a day

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Fibre

Fibre or roughage is the name for a group of complex carbohydrates that are found naturally in plant foods such as cereals, nuts, beans, fruit and vegetables. Unlike other carbohydrates fibre is not fully broken down by the body (digested) but instead passes completely through the digestive system and is excreted via the faeces.

There are two main types of fibre:

• soluble• insoluble

Insoluble fibre is important in our diet because it absorbs water and makes food bulkier and softer, it also allows the muscles of the digestive system greater grip making them more efficient, speeding up the passage of waste through the body.

People who do not consume enough fibre in the diet appear to be more likely to suffer from constipation and diseases of the digestive system. The best sources of insoluble fibre are unrefined cereals such as wheat and their products (i.e. wholemeal bread), brown rice and wholemeal pasta.

Soluble fibre is found in oats and pulses (beans, peas, lentils). It contains soluble gums, which form thick gels. These gels delay the absorption of glucose into the blood stream. This is particularly beneficial to diabetics who would otherwise experience a massive rise in blood-sugar levels with insufficient insulin to cope.

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Pectin is also a soluble fibre it is found in most ripe fruits and vegetables such as carrots. Pectin also forms a gel, which helps with the passage of food through the intestines. It also protects against the effects of certain toxic chemicals and helps to lower cholesterol and fat levels.

The greatest concentration of fibre is contained in the external surface of plant food, ie the potato skin, apple peel and the outer layer of brown rice or cereal grains. It follows therefore, that refining food often reduces its fibre content, as the valuable outer coating is generally removed. Cooking reduces the amount of fibre even further, so it is important to eat fresh fruit and vegetables, raw if possible.

To increase fibre in the diet to the recommended intake of approximately 30g per day, it is not necessary to change eating habits drastically. For example, eat wholemeal bread instead of white, and eat brown rice or wholemeal pasta and breakfast cereals made from whole grains or oats. Also ensure a good intake of whole fruit and vegetables - leaving the skins on whenever possible. Eat more dried fruits, pulses and nuts.

Remember it is also important to drink plenty of fluid. This will replace the water absorbed by the fibre - otherwise constipation may still occur. It is also advisable to increase fibre intake very gradually. Some individuals become bloated and experience flatulence or stomach ache if they suddenly change from a diet that is high in processed food to one that is high in fibre

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Non-starch Polysaccharide (NSP) Components and their Properties

Fibre comes in various forms. In natural fibre-rich foods it is closely mixed up with other complex carbohydrates. Fibre-rich foods fall into four main groups.

CerealsMost cereals, particularly whole grain cereals (as in wholemeal brad and brown rice) are good sources of fibre. The fibre they provide works in the gut keeping it working smoothly and efficiently. For this reason they are very good are relieving constipation.

Peas and Beans (Pulses)Peas and beans are rich in gums and mucilages which play a part in controlling the level of sugar in the blood. They may prove to be an important in the diet for diabetics.

Root VegetablesRoot vegetables (potatoes, carrots, parsnips, turnips, Swedes) are high in fibre and starch. Potatoes provide reasonable amounts of protein and vitamin C.

Fruit and leafy vegetables Includes cabbage, lettuce and spinach. As they are mainly water they are much more diluted sources of fibre. Advantageous to slimmer’s as they are also a dilute source of calories. Some fruits are particularly rich in pectin, which may play a apart in reducing cholesterol in the blood.

Properties of Non-Starch Polysaccharides

Cellulose (all vegetable tissues): insoluble in water but can absorb water and swell; has limited faecal bulking capacity.

Hemicelluloses (all vegetables tissues, especially cereal husks): slightly soluble in water and absorbs large amounts of water; promote the formation of large bulky stools; binds strongly to bile salts and promotes their excretion from the gut.

Pectins (significant amounts found only in fruit): very water soluble and capable of forming a gel at low concentrations; form strong associations with bile salts and promotes the excretion of the latter from the intestine.

Lignin (cereals and old, woody vegetables): very insoluble in water and resistant to degradation in the gastro-intestinal tract; binds to bile salts.

Gums and Mucilages (pulses = peas and beans): all have a marked ability to form bulky gels at low concentrations and many form strong associations with molecules such as bile acids.

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Phytate

Many people associate fibre with ‘bran’, the outer layer of cereal grains which are rich in the fibre lignin. Whilst adding bran can relieve constipation, the rest of the diet can still be poor, in that it may contain a high amount of refined foods; meat, dairy products and sugars. Thus constipation is best relieved by increasing the intake of whole grain (ie unrefined) cereals, beans vegetables and fruit.

Raw bran contains a substance known as phytate which makes it difficult for the body to absorb iron, zinc and calcium. Some phytate is destroyed if the bran is cooked. Even more phytate is destroyed when combined with yeast during the bread making process. Some people would argue that most people have more than enough calcium, zinc and iron the diet, thus the effect of phytate is not important however, groups known to be at risk are:

AsiansThe Asian diet tends to be deficient in vitamin D. Traditional bread, chapattis, are unleavened and so the phytate is incorporated into their diet.

Elderly peopleElderly people may have a reduced ability to absorb calcium and a tendency to suffer from constipation and may, therefore, add bran to their diet.

Women with heavy periodsWomen with heavy periods, and as a result, experience a large blood loss and need to have increased iron in their diets.

Pregnant women Many pregnant women suffer from constipation and may be tempted to add bran to their diets. A zinc deficiency in the mother’s diet may be related to babies who are low in weight at birth (but are not premature).

SlimmersMany slimmers suffer from constipation due to the fact that they cut out or reduce their intake of potatoes, bread, beans, rice, breakfast cereals and pasta which contain the most concentrated forms of fibre. They may rely on vegetables and fruit only for dietary fibre which may result in a low fibre intake. For example, you would have to eat a whole lettuce to obtain the same amount of fibre as a portion of beans, a bowl of breakfast cereal, or two slices of wholemeal bread.

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Data has been collected linking a deficiency of NSP to a range of diseases. A great deal of this information is indirect and should not be confused with a demonstrated cause and effect relationship. However, the claims that fibre in the diet may prevent or ease the symptoms of many ‘Western Diseases’ are based up the fact that increased fibre consumption in humans for different times and under a variety of conditions, almost without exception produces beneficial results. The most obvious result of an increase in NSP consumption is a decreased intestinal transit time and the production of bulk stools that are easy to eliminate. It is not just uncomfortable to be constipated. Possible harmful waste products hang about for much longer. So a decreased transit time is good.

Origin Transit Time Stool WeightEuropeans 70 hours 100 gramsVegetarian Europeans 43 hours 180 gramsRural Africans 35 hours 400 grams

In one experiment children were given a harmless plastic marker to swallow with one meal. It took anything from one day to a whole week for the marker to pass through them.

Diverticulitis

Small hared faeces, characteristic of a low-fibre diet, are more difficult to propel along the gastro-intestinal tract and require more powerful muscle contractions, which cause an increase in intra-luminal pressure, especially in the colon. Pressures inside the colon can become so great that they cause ballooning out of the inner lining of the colon wall though the surrounding muscle giving rise to diverticular (small pouches) and diverticulitis if they become inflamed. Elimination of hard stools requires considerable effort and this straining at stool causes a build up of intra-abdominal pressures. This pressure is transmitted to veins and the diaphragm and is thought to predispose varicose veins, hiatus hernias and haemorrhoids.

These diseases are usually associated with middle and old age, but a survey of 4 to 5 year old children shows that nearly one in fifteen was suffering from constipation associated with a low fibre diet. Clearly, dietary patterns established in children could have a profound effect on health in later life.

NSP is also thought to regulate the acidity of gastric juices. It also helps to retain liquids which normalise acidity in the stomach, preventing gastric juices leaving the stomach prematurely and causing problems such as duodenal ulcers.

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Appendicitis

Appendicitis is another problem related to low fibre diets. On the basis of experimental evidence, acute appendicitis seems to be the end result of a primary obstruction of the appendix lumen (the inside space of a tubular structure). Once this obstruction occurs, the appendix subsequently becomes filled with mucus and swells, increasing pressures within the lumen and the walls of the appendix, resulting in thrombosis and occlusion of the small vessels, and stasis of lymphatic flow. Rarely, spontaneous recovery can occur at this point. As the former progresses, the appendix becomes ischemic and then necrotic. As bacteria begin to leak out through the dying walls, pus forms within and around the appendix (suppuration). The end result of this cascade is appendiceal rupture (a 'burst appendix') causing peritonitis, which may lead to septicemia and eventually death.

The causative agents include foreign bodies, trauma, intestinal worms, lymphadenitis, and, most commonly, calcified fecal deposits known as appendicoliths or fecaliths The occurrence of obstructing fecaliths has attracted attention since their presence in patients with appendicitis is significantly higher in developed than in developing countries, and an appendiceal fecalith is commonly associated with complicated appendicitis. Also, fecal stasis and arrest may play a role, as demonstrated by a significantly lower number of bowel movements per week in patients with acute appendicitis compared with healthy controls. The occurrence of a fecalith in the appendix seems to be attributed to a right-sided fecal retention reservoir in the colon and a prolonged transit time. From epidemiological data, it has been stated that diverticular disease and adenomatous polyps were unknown and colon cancer exceedingly rare in communities exempt from appendicitis. Also, acute appendicitis has been shown to occur antecedent to cancer in the colon and rectum. Several studies offer evidence that a low fiber intake is involved in the pathogenesis of appendicitis. This is in accordance with the occurrence of a right-sided fecal reservoir and the fact that dietary fiber reduces transit time.

Cancer of the Colon

The case is far from proven that fibre might be protective against this disease. It is assumed that caner of the colon is a result of bacteria converting bile salts into carcinogenic substances in the lumen that come into contact with the colon cell wall. High fibre diets and the resultant bulky (more dilute) fast moving stools will reduce the contact (and hence the cancer risk) of those substance with the intestinal mucosa.

Whilst countries whose population consumes large amounts of dietary fibre have a low incidence of colon cancer compared with low-fibre communities, it has not been possible to establish the exact reasons for the differences. Dietary fibre is only one of several factors that may play.

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Cholesterol Metabolism and Diabetes

Dietary fibers have three primary mechanisms: bulking, viscosity and fermentation. Dietary fibers can change the nature of the contents of the gastrointestinal tract, and to change how other nutrients and chemicals are absorbed through bulking and viscosity. Some types of soluble fibers bind to bile acids in the small intestine, making them less likely to enter the body; this in turn lowers cholesterol levels in the blood. Viscous soluble fibers may also attenuate the absorption of sugar, reduces sugar response after eating, normalizes blood lipid levels and, once fermented in the colon, produce short-chain fatty acids as byproducts with wide-ranging physiological activities (discussion below). Insoluble fiber is associated with reduced diabetes risk, but the mechanism by which this occurs is unknown. One type of insoluble dietary fiber, resistant starch has been shown to directly increase insulin sensitivity in healthy people, in type 2 diabetics, and in individuals with insulin resistance, possibly contributing to reduced risk of type 2 diabetes.

In June 2007, the British Nutrition Foundation issued a statement to define dietary fiber more concisely and list the potential health benefits established to date:

‘Dietary fibre’ has been used as a collective term for a complex mixture of substances with different chemical and physical properties which exert different types of physiological effects. The use of certain analytical methods to quantify dietary fiber by nature of its indigestibility results in many other indigestible components being isolated along with the carbohydrate components of dietary fiber. These components include resistant starches and oligosaccharides along with other substances that exist within the plant cell structure and contribute to the material that passes through the digestive tract. Such components are likely to have physiological effects. Yet, some differentiation has to be made between these indigestible plant components and other partially digested material, such as protein, that appears in the large bowel. Thus, it is better to classify fiber as a group of compounds with different physiological characteristics, rather than to be constrained by defining it chemically. Diets naturally high in fiber can be considered to bring about several main physiological consequences:

helps prevent constipation reduces the risk of colon cancer improvements in gastrointestinal health improvements in glucose tolerance and the insulin response reduction of hyperlipidemia, hypertension, and other CHD risk factors reduction in the risk of developing some cancers increased satiety and hence some degree of weight management

Therefore, it is not appropriate to state that fiber has a single all encompassing physiological property as these effects are dependent on the type of fiber in the diet. The beneficial effects of high fiber diets are the summation of the effects of the different types of fiber present in the diet and also other components of such diets. Defining fiber physiologically allows recognition of indigestible carbohydrates with

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structures and physiological properties similar to those of naturally occurring dietary fibers.

Sources of soluble and insoluble fibre

Classification Plant sources Food examplesInsoluble Wheat Wholemeal bread, wheat-based cereals, baked

products made with wholemeal flourMaize Cornbread, fresh and frozen cornRice Especially brown ricePasta Especially wholemeal pastaFruits Rhubarb, berries eg logan berriesLeafy vegetables Cabbage, Brussels sproutsPulses Peas, chick peas, broad-beans, lentils

Soluble Oats Porridge, oat based breakfast cereals, out bread

Barley Pearl barleyRye Bread, crisp breadsFruits Most fruits especially with the skin dried fruits

eg prunes, figs, apricotsVegetables Carrots, parsnipsPulses Baked beans, kidney beans

Summary of Recommendations for Dietary Fibre

Dietary RequirementDaily Recommended Amount (DRA) Approx 30 grams (NACNE Report)Dietary Reference Value (DRV):1991 UK Department of Health Dietary Reference Values for Food Energy and Nutrients

18 grams (Englyst Analysis)

Children should eat proportionately less. Under 2 years of age, NSP starch polysaccharide rich foods should not replace other energy rich foods which are needed for adequate growth.

Women and older people with low energy intake may have difficulty in achieving an adequate intake of NSP, so particular attention should be paid to ways of achieving this.

The aim of the DRV is to achieve an increase in average faecal stool weight of 25%. Stoll weight is not increased further with excessive intakes of NSP so the Panel (COMA) gave a recommendation that 32g/day should not be exceeded.

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Simple advice to give to clients with regard to fibre is look at your stools when on the toilet. If they sink you may need more fibre, if they are runny you may need less fibre and if they float you are probably getting the correct amount of fibre.

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FATS

Functions of Fat

As a source of energy For insulation/protection As carriers of fat soluble vitamins (A, D, E, & K) For making important structures in the body such as hormones

Fats or liquids are found' in the body in the following main forms:

triglycerides phospholipids cholesterol

The fats found in food consist mainly of mixtures of triglycerides. Triglycerides are stored in fat cells (adipose tissue), they are used as fuel. The basic structure of a triglycerides is one molecule of a compound called glycerol attached to three molecules of free fatty acids (FFA's).

Chemical bond

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GLYCEROL

Fatty Acid

Fatty Acid

Fatty Acid


The free fatty acids form the fuel part of the molecule. There are many different kinds of free fatty acids, however the three most common types are:

• stearic acid• oleic acid• palmitic acid

Just like carbohydrates free fatty acids contain atoms of carbon, hydrogen and oxygen; however they differ in the number and the arrangement of each of the atoms. Free fatty acids are basically long chains of carbon, with hydrogen attached and a little bit of oxygen. For example, palmitic acid contains a long chain of 16 carbon atoms. Each carbon atom is saturated with hydrogen atoms. (When there is a hydrogen atom at every available spot in the molecule the fatty acid is said to be saturated, in other words it contains all the hydrogen that is possible).

C16H32O2

C = CarbonH = HydrogenO = Oxygen

When some hydrogen is missing, the molecule is called an unsaturated fatty acid. If just one atom of hydrogen is missing - the fatty acid is said to be monounsaturated. If two or more atoms of hydrogen are missing, the fatty acid is said to be polyunsaturated.

You are probably aware of the terms, saturated, monounsaturated and polyunsaturated with reference to fats. These terms can be misleading as no fat or oil is made up of just one type - they contain a mixture of them all. Each fat is described by the kind of fatty acid that features most in its composition. For example, a polyunsaturated margarine will also contain a small amount of saturated fatty acids as well. ·

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Saturated Fats

Saturated fats include those fats which are normally hard/solid at room temperature i.e. lard and butter. Too much of this kind of fat can cause cholesterol levels to increase in some individuals. This in turn increases the risk for developing heart disease.

Saturated fats are found mainly in animal foods/products these include:

• dairy products (milk, cheese, yoghurt, cream & butter)• meat and meat products such as sausages, pies etc.• eggs• lard (animal fat)

they are also found in:

• processed foods such as chocolate, cakes, biscuits, pastries, crisps etc.• some fat spreads• some vegetable oils such as palm oil and coconut oil

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Monounsaturated Fats

Monounsaturated fatty acids have slightly less hydrogen - their carbon chain contains one unsaturated carbon atom.

Oils high in monounsaturates are usually liquid at room temperature but turn solid in cold temperatures.

The richest sources of monounsaturates include:

• Olives and olive oil• Rapeseed oil• Groundnut oil• Hazelnut oil• Almond oil

Monounsaturates have health benefits as they can help to reduce total cholesterol levels in the blood without affecting (or reducing) the beneficial high density lipoproteins (HDL) cholesterol.

Polyunsaturated Fats

Polyunsaturated fats have the least hydrogen (they have two or more unsaturated carbon atoms). Oils high in polyunsaturated fats are liquid at both room and cold temperatures.

Some polyunsaturated fats cannot be made by the body. Consequently they must be supplied by the diet. These are called essential fatty acids. These essential fatty adds can be split into two types:

• Omega 6 - which originates from the essential fatty acid linolenic add• Omega 3 - which originates from the essential fatty acid linoleic add.

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Omega 6 fatty acids are found mainly in vegetable oils (eg corn oil, sunflower oil and safflower oil), grains and nuts.

Omega 3 fatty acids are found mainly in seafood in particular oily fish (eg sardines, herring, mackerel and salmon), vegetable oils (eg soya, rapeseed and linseed oils) walnuts and leafy vegetables.

Virtually all fish contain some omega 3 oils, however the lighter the colour of the fish the less oil it contains and consequently it provides less omega 3. Fish with darker flesh such as herring, mackerel, pilchards, sardines or salmon provide much more. ·

Both types of polyunsaturated fats (omega 3 and omega 6) are essential for good health. Each has a different role within the body. Modern diets supply mostly the Omega 6 type.

Essential fatty acids provide important health benefits, they form a vital part of cell membranes and are converted into hormone like substances (prostaglandins*, thromboxanes and leukotrienes), these control many functions in the body such as:

·

blood dotting - blood becomes less sticky and less likely to form unwanted blood dots

widening and narrowing of blood vessels they help to lower blood pressure, particularly in those with high blood

pressure they help to reduce the amount of fat in the blood, this helps the blood to flow

more easily round the body, they also help to control blood cholesterol levels they help to diminish inflammatory processes reducing the pain of conditions such as

arthritis and psoriasis they help to maintain the immune system omega 3 fatty adds also form an important part of brain tissue they help to make skin watertight.

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http://nomoredirtylooks.com/2012/03/meatless-monday-an-ode-to-nuts%E2%80%94whats-your-favorite/mixed-nuts/


Deficiency in omega-6 fatty acids (sometimes found in babies fed on skimmed milk and patients who are unable to absorb fats) can lead to poor growth, skin problems, blood clots and an impaired immune system.

An adult requires about 4g omega-6 fatty acids a day (equivalent to 2 teaspoons of sunflower oil or a handful of almonds or walnuts; more may offer some protection from heart disease. An upper daily limit of 25g is suggested as very high intake may be harmful as they increase the production of free radicals**. Linoleic acid has also been show to promote tumour growth in animals.

Omega-3 fatty acids are needed in smaller amounts 1-2g per day found in 100g of herring, 1-2 teaspoons of linseed or rapeseed oil, or a handful of walnuts.

* A prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body. Every prostaglandin contains 20 carbon atoms, including a 5-carbon ring.

They are mediators and have a variety of strong physiological effects, such as regulating the contraction and relaxation of smooth muscle tissue. Prostaglandins are not endocrine hormones, but autocrine or paracrine, which are locally acting messenger molecules. They differ from hormones in that they are not produced at a discrete site but in many places throughout the human body. Also, their target cells are present in the immediate vicinity of the site of their secretion (of which there are many).

** The free-radical theory of aging states that organisms age because cells accumulate free radical damage over time. A free radical is any atom or molecule that has a single unpaired electron in an outer shell. While a few free radicals such as melanin are not chemically reactive, most biologically-relevant free radicals are highly reactive. For most biological structures, free radical damage is closely associated with oxidative damage. Antioxidants are reducing agents, and limit oxidative damage to biological structures by passivating free radicals.

Denham Harman first proposed the free radical theory of aging in the 1950s, and in the 1970s extended the idea to implicate mitochondrial production of reactive oxygen species.

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Omega-6 Fatty Acids

Linoleic acidHemp, sunflower, pumpkin and sesame seeds or their oils

Converted to GLA (Gamm-linolenic acid) found in Evening Primrose Oil

Converted to DGLA (di-homo gamma linolenic acid)

Converted to Prostaglandins type 1

Reasons for Omega-6 Fatty Acids Deficiency

Many people omit oils and fats from their diet because of the calories content, and the mistaken belief that all fats are bad. Smoking, drinking alcohol and stress in its various forms (chemical, emotional, physical and mental) reduce omega-6 absorption. The enzyme delta-6-desaturase, which is dependent on vitamin B1, biotin, zinc and magnesium is essential for conversion of linolenic acid into gamma-linolenic acid. Without the GLA human beings cannot make DGLA or prostaglandins type 1. For that reason people with vitamin and mineral deficiency are likely to be affected by deficiency in omega-6 fatty acids.

Deficiency Signs & Symptoms of Omega-6 Fatty Acid

Inflammatory conditions eg arthritis and asthma Difficulty in losing weight Dry eyes and skin, including eczema High blood pressure PMS or breast pain Blood sugar problems or diabetes Excessive thirst Multiple sclerosis Need to drink alcohol every day Mental health problems

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Omega-3 Fatty Acids

Linolenic acidGroundnut oil, vegetable leaves, linseeds, safflower oil, almonds, walnuts

Converted to EPA (eicosaopentonic acid) andDHA (docosahexaenoic acid)

Sardines, herring, mackerel, salmon, tuna

Converted to Prostaglandins type 3

Deficiency Signs & Symptoms of Omega-3 Fatty Acid

Inflammatory health problems Difficulty in losing weight Dry skin High blood pressure Impaired vision Prone to infections Fluid retention Memory and learning ability impaired

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Trans Fatty Acids (Trans Fats)

Fat spreads are a mixture of hydrogenated oil and water (or skimmed milk), plus a large amount of emulsifiers (these prevent the two substances from separating).

Hydrogenation is a process that makes oils become hard. Hydrogenation causes fats to become saturated, it also causes 'trans' fatty acids to be formed. Some 'trans' fatty acids have been shown to raise the level of triglycerides in the blood, (this increases the thickness of the blood and increases its tendency to clot) they also appear to increase cholesterol levels.

The Department of Health's committee recommends no more than 2% of all our energy intake should come from ‘trans’ fats (approximately 4g per day). Most current intakes are around 5g per day.

Fat spreads appear to provide nearly one third of 'trans' fatty acids in our diet. However, biscuits, cakes, pastries, puddings and ice cream also provide significant amounts.

To keep the intake of 'trans' fatty acids low, avoid processed foods, hydrogenated spreads, and when frying foods, do not re-use the cooking oil (trans fatty acids are also formed when you re-heat cooking oil).

Other health risks

There are suggestions that the negative consequences of trans fat consumption go beyond the cardiovascular risk. In general, there is much less scientific consensus asserting that eating trans fat specifically increases the risk of other chronic health problems:

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Alzheimer's Disease: A study published in Archives of Neurology in February 2003 suggested that the intake of both trans fats and saturated fats promote the development of Alzheimer disease, although not confirmed in an animal model. It has been found that trans fats impaired memory and learning in middle-age rats. The rats' brains of trans-fat eaters had fewer proteins critical to healthy neurological function. Inflammation in and around the hippocampus, the part of the brain responsible for learning and memory. These are the exact types of changes normally seen at the onset of Alzheimer's, but seen after six weeks, even though the rats were still young.

Cancer: There is no scientific consensus that consumption of trans fats significantly increases cancer risks across the board. The American Cancer Society states that a relationship between trans fats and cancer "has not been determined." One study has found a positive connection between trans fat and prostate cancer. However, a larger study found a correlation between trans fats and a significant decrease in high-grade prostate cancer.

Diabetes: There is a growing concern that the risk of type 2 diabetes increases with trans fat consumption. However, consensus has not been reached. For example, one study found that risk is higher for those in the highest quartile of trans fat consumption. Another study has found no diabetes risk once other factors such as total fat intake and BMI were accounted for.

Obesity: Research indicates that trans fat may increase weight gain and abdominal fat, despite a similar caloric intake. A 6-year experiment revealed that monkeys fed a trans fat diet gained 7.2% of their body weight, as compared to 1.8% for monkeys on a mono-unsaturated fat diet. Although obesity is frequently linked to trans fat in the popular media, this is generally in the context of eating too many calories; there is not a strong scientific consensus connecting trans fat and obesity, although the 6-year experiment did find such a link, concluding that "under controlled feeding conditions, long-term TFA consumption was an independent factor in weight gain. TFAs enhanced intra-abdominal deposition of fat, even in the absence of caloric excess, and were associated with insulin resistance, with evidence that there is impaired post-insulin receptor binding signal transduction."

Liver Dysfunction: Trans fats are metabolized differently by the liver than other fats and interfere with delta 6 desaturase. Delta 6 desaturase is an enzyme involved in converting essential fatty acids to arachidonic acid and prostaglandins, both of which are important to the functioning of cells.

Infertility in women: One 2007 study found, "Each 2% increase in the intake of energy from trans unsaturated fats, as opposed to that from carbohydrates, was associated with a 73% greater risk of ovulatory infertility...".

Major depressive disorder: Spanish researchers analysed the diets of 12,059 people over six years and found those who ate the most trans fats had a 48 per cent higher risk of depression than those who did not eat trans fats. One mechanism may be trans-fats' substitution for docosahexaenoic acid (DHA) levels in the orbitofrontal cortex (OFC). When the brains of 15 major depressive subjects who had committed suicide were examined post-mortem and compared against 27 age-matched controls, the suicidal brains were found to have 16% less (male average) to 32% (female average) less DHA in the OFC.

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Which spread is really the best for you?

The following spreads have been scored out of 5 (1 is the worst and 5 is the best for health).

HIGH IN POLYUNSATURATES

Typical fat content 70%

These spreads are usually made with sunflower oil and supply at least a 2-1 ratio of polyunsaturated fats to the less healthy saturated type. The may help to reduce cholesterol as long as they are eaten as part of a diet that is overall low in fat. To classify as ‘heart healthy’, the spreads should ideally also be free from, or very low in (less that 0.5%) trans fats (look the term hydrogenated fats).

Best for: anyone keeping a watchful eye on their cholesterol levels.

HEALTH RATINGS: Flora 3; Flora Buttery 3; Vitalite 3.5; Vitalite Buttery 3.5

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HIGH IN MONOUNSATURATES

Typical fat content 60-80%

Olive oil and rapeseed oil are an important ingredient in these spreads, making them richer in monounsaturates than other types. Studies show that monounsaturates have at least as favourable an effect on cholesterol as polyunsaturates. They are less prone to oxidation, which is linked to possible increased cancer risk, when they end up in body tissues. But keep an eye out for added hydrogenated oils, to avoid loading up with trans fats.

Best for: 40 plus group and people who don’t usually eat olive or rapeseed oil.

HEALTH RATINGS: Olivio 4; Utterly Buttely 2.5; Granose Olive Grove 2

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LOW FAT


Even though these spreads should, in theory, be healthier than those that are higher in fat. In practice they are a bit of a health minefield. The main problem is trans fats, so look for those that list hydrogenated fats or oils on the ingredients list. A general rule, the lower in fat the spread is the more likely it is to be bolstered with addition of thickeners and emulsifiers. Vegetarians should also check labels for animal gelatine as the ingredient can crop up in some low fat spreads.

Best for: People on diets or who have been ordered to cut down their fat and saturate intake.

HEALTH RATINGS: Gold Lowest 3; Gold Semi-Skimmed 2; I Can’t Believe It’s Not Butter Light 3.5; Anchor Half Fat 4; Vitalite Light 2.5.

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BUTTER


An average spreading of butter on two slices of toast accounts for more that 10% of the daily guideline fat intake for women and half the maximum desirable saturate intake. Spreadable butter has up to 30% vegetable oil (usually sunflower) added, which makes it slightly better for your arteries. The small amount of trans fats that occur in butter do so naturally, and aren’t thought to be associated with harmful side effects in the same way as the man-made variety.

Best for: Young children, people who aren’t at high heart disease risk.

HEALTH RATINGS: Natural Butter 1; Anchor Spreadable 1.5; Lurpak Spreadable 1.5; Anchor Organic 2.

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FAT SUBSTITUTED


SIMPLESSE is a milk-derived ingredient which gives a feel similar to fat in the month. Spreads containing this ingredient can be as low as 5% fat, with the trade off being a high water content and added bulking ingredients such as processed carbohydrates. The big bonus is that the spread contains virtually no harmful saturated fat.

Best for: Very overweight people, people with special dietetic needs.

HEALTH RATINGS: Tesco Sunflower 4.

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BENECOL

Typical fat content 40% or 80%

Benecol contains stanol ester, a plant substance that physically blocks the absorption of cholesterol from the gut. Studies show that eating Benecol in amounts equivalent to 4-6 slices of bread thinly spread with the product daily reduces total cholesterol by one tenth which can equate to a reduction of about 20% in heart disease. The fall is almost exclusively in bad cholesterol.

Best for: People with a high cholesterol level or at high genetic ricks of heart disease.

HEALTH RATINGS: Benecol Light 5; Benecol 4.5.

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OTHERS


Most of the spreads that are left fit into the medium to high fat bracket. They contain up to half the saturated content of butter, but the composition is very variable, depending on the precise ingredients. Those containing semi-solid palm oil or buttermilk tend to be higher in saturates.

Best for: People with a high cholesterol level or at high genetic ricks of heart disease.

HEALTH RATINGS: Benecol Light 5; Benecol 4.5.

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What Happens to Fat Following Digestion?

Triglycerides can be combined with oxygen (oxidised) to produce energy. Each gram of fat can yield 9 kcal. Excess fat is stored mainly in fat tissue (adipose tissue) until it is needed. Fat tissue also insulates and protects the body. About half of stored fat is deposited under the skin. Deposited fats are renewed about once every 2-3 weeks, this is because fat is continually being released from storage, transported by the blood and re-deposited in other fat cells.

Fat which is stored in adipose tissue makes up the largest reserve of energy in the body. Even though the body is able to store much more fat than glycogen, fats are still the body's second choice when it comes to supplying energy.

Liver cells can create fats from glucose or some amino acids. This can happen when a large quantity of carbohydrate or protein enters the body – more than can be used at that moment in time. This process is complex and is enhanced when particular hormones (such as insulin), are present in the blood stream.

Not all fats are used as an energy source. Some types of fat are used as structural molecules or used to create other substances that are essential to the body. For example, phospholipids are used for making cell membranes and prostaglandins (molecules that function like hormones). Cholesterol is another type of fat - it is used in the construction of bile salts and steroid hormones.

How Much Fat Should We Consume?

The UK Government recommends that for health no more than 35% of all the calories we eat each day should come from fat. For athletes the International Conference of Foods Nutrition and Sports Performance recommends an intake between 15% - 30 %.

Most of this fat intake should be in the form of unsaturated fats. Remember these are found in:

• Vegetable oils eg corn or olive oil• Seeds eg sunflower, sesame• Nuts eg groundnut• Peanut butter• Oily fish eg mackerel, pilchards, sardines

Summary of Recommendations for Fats

1991 UK Department of Health Dietary Reference Values for Food Energy and Nutrients

Average Percentage of food Energy

Saturated Fatty Acid Not more than 11%Polyunsaturated Fatty Acid 6.5%Monounsaturated Fatty Acid 13%Trans fats Not more than 2%Total Fat Not more than 35%

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PROTEIN

The body of an average-sized adult contains between 10 - 12 kg (160,000 KJ) of protein (McKardle,Katch & Katch,1999). Protein has two main functions within the body:

It forms part of the structure of every cell in the body (including enzymes and hormones),consequently it is needed for the formation and/or repair of all tissues.

It is a source of energy if glucose is in short supply (thus there is a danger that those people on low calorie or low carbohydrate diets will bum lean tissue as an energy source).

Proteins are large complex molecules. In addition to carbon, hydrogen and oxygen, proteins also contain about 16% nitrogen along with sulphur and occasionally phosphorous, cobalt and iron (McKardle, Katch & Katch, 1999).

When proteins are digested (broken down) they are separated into basic units called amino acids.

There are 20 different amino acids required by the human body. Eight of them (nine in children and some older adults), cannot be synthesized so they must be consumed within the diet, consequently they are referred to as essential amino acids. These are isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Children also require histidine. The body is able to manufacture the remaining nonessential amino acids.

The remaining amino acids are Alanine, arginine, aspartic acid, aspargine, cysteine, glutamic acid, glutamine, glycine, proline, serine, tyrosine.

Note that the term ‘nonessential’ does not mean that these amino acids are unimportant. Nonessential amino acids are still vital to the human body they are termed ‘nonessential’ because these particular amino acids can be synthesized from other compounds already found in the body, and at a rate that meets the demands for normal growth and repair of tissue.

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Both animals and plants manufacture proteins that contain essential amino acids. No health or physiological advantage exists from an amino add obtained from an animal source compared to the same amino acid obtained from a plant source.

Protein Sources

The usefulness of a food high in protein is often measured by how many amino acids are contained within it. This is often referred to as its Biological Value or BV Biological Value refers to its completeness for supplying essential amino acids. Egg white has a BV of 100. This means that it contains all the amino acids (both essential and nonessential), in the right proportions needed by the human body. Plant proteins, such as those in cereals, pulses and nuts generally have one or more to the essential amino acids wither missing, or in short supply. For example, wheat and rice proteins are comparatively low in lysine. Legumes such as lentils are low in tryptophan and methionine. These proteins are therefore said to have low biological values, because the quality of a protein depends on its ability to supply all the indispensable/essential amino acids in the amounts needed.

Other foods which have a high BV are shown below:

Meat poultry fish dairy products (except butter)

High-quality protein foods (also referred to as 1st class protein or complete protein), comes from animal sources. Whereas vegetables (lentils, dried beans and peas, nuts and cereals), are incomplete in one or more of the essential amino acids, thus giving a relatively lower biological value (often referred to as 2nd class or incomplete protein).

The table below rates some common sources of protein in the diet.

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(Source: McKardle, Katch & Katch 1999 p31)

McKardle,Katch & Katch (1999) note that currently, animal sources of protein provide almost two-thirds of the dietary protein consumed, whereas 50 years ago protein consumption occurred equally from plants and animals. The current, relatively high intake of cholesterol and saturated fatty acids comes from this over reliance on animal sources for dietary protein.

Protein formation is carried out in virtually every cell of the body. Once the necessary amino acids are present inside the cell, protein can be formed.

Protein breakdown occurs every day in all the body's tissues. Proteins are taken from worn out cells such as red blood cells and are broken down again into amino acids. Some of these amino acids can then be recycled to make new proteins. Those that can't be recycled are excreted. Because proteins form the main part of virtually every cell structure - higher protein intake is important during:

• growth• pregnancy• recovery from disease or injuries

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,


As noted earlier, protein can also be used as a source of energy - each gram of protein yields approximately 4kcal/g (the same as a gram of carbohydrate). However, energy provision is not the main role of protein. As long as the body takes in and stores enough carbohydrates it will use very little protein as an energy source. If glycogen (stored glucose) is in short supply (for example when dieting/fasting or towards the end of a long, hard workout), larger quantities of protein are then used for energy. The main source of this protein is the muscles and organs of the body. Over time large amounts of lean tissue can be lost, leading to little or no improvements in fitness levels and signs of over training.

What about Vegetarians?

Grains and legumes (peas, beans and lentils) are excellent protein sources, however they do not provide the full range of essential amino acids (an exception to this may be well-processed, isolated soy-bean protein, termed soy-protein isolates - this protein ranks equivalently to some animal proteins).

Grains do not possess the essential amino acid lysine, while legumes contain lysine but lack the essential amino acid methionine (found abundantly in grains). Thus, when incomplete or low biological value proteins are combined they form 'complete' proteins of 'high biological value'.

The following combinations of food provide a full range of

amino acids:

Grains & Milk Products (for lacto-vegetarians):

Cereal and milkBread and cheesePasta and cheese

Grains & Pulses (peas, beans, lentils):

Rice and beans Lentil soup with a bread rollCroutons and pea soup Tortillas and beansBeans on toast Corn bread and chilli beans

Grains & Nuts:

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Peanut butter sandwich

Legumes & Seeds:

Hummus (a blend of chic peas and tahini which is made from sesame seeds)Tofu and sesame seeds

By combining the above foods vegetarians can plan their diets to ensure they consume an adequate amount of protein each day. However, lacto-ovo vegetarians (vegetarians that still consume dairy products and eggs) need to take care as both cheese and eggs have a higher saturated fat and cholesterol level than lean meats.

Vegetarians may also lack iron and zinc (minerals found primarily in meat and other animal products). Iron is vital for red blood cell formation and zinc is important for tissue growth and maintenance. Both iron and zinc in animal protein is also more easily absorbed than that obtained from plants, making it even more likely that vegetarians or vegans may suffer from a deficiency. Plant foods that are high in zinc include beans, lentils and wholegrains.

Recent Events

The terms ‘first class protein’/‘high biological value’ and ‘second class protein’/‘low biological value’ may be considered obsolete due to the following:

By weight steak is only 17.4% complete protein and it also contains 25.3% fat. Therefore, as a food, it is unbalanced. Its excessive consumption leads to a dangerous consumption of fat which can be deposited in the body’s stores and arteries and an increased risk of colon cancer.

In percentages of calories provided:

A slice of lean ham is about 25% protein; the remaining 75% is fat. A carefully trimmed, lean, cooked piece of beef contains 65% protein and

35% fat. Untrimmed it is 24% protein and 76% fat. Wholegrain bread contains 14% protein, 9% fat and 70% unrefined

carbohydrate. Cooked beans contain 36% protein, less that 6% fat and 58% unrefined

carbohydrate.

Thus, in general, all red meats are not the best source of protein. The most efficient animal protein is found in eggs which produce a higher proportion of usable protein than steak.

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Soya bean contains more protein which is totally usable (ie it is complete protein with all the 8 essential amino acids) than any meat. By weight soya bean has 34% protein and 18% fat of which 11% is polyunsaturated. However, it is always necessary to have a mixture of different types of vegetable protein in one meal when vegetable sources of protein are used.

There are other points about protein which are not often fully realised. If typical menus from around the world are based primarily on grains and vegetables, peas and beans, (with only about a tenth of the protein coming from meat, milk and eggs), it has been found that a diet sufficient to supply 2500 Kcal/day, which is an ample intake for most people, would supply one and a half times the protein needed by 98% of the population. It is very difficult on a mixed vegetable diet to produce a loss of body protein unless high levels of sweet things and other protein-free foods are taken.

The total amount of protein per day an average adult can remain in good health on is 40g of protein.

How Much Protein Do We Need?

The normal adult daily requirement of protein is approximately 0.75g per kg of bodyweight. This amount is easily obtained from a well balanced diet in which 12-15% of the calories eaten are from protein sources.

For those involved in heavy exercise (athletes) the protein requirement is slightly increased to 1.2- 1.7g per kg of bodyweight (1.2-1.4 for endurance athletes and 1.7 for power lifters).

The amount of protein each individual requires, is related to the total amount of calories (energy) needed per day. In other words, as your need for more energy increases because you are more active - so does your need for protein. This is why the International Conference on Foods, Nutrition and Sports Performance (1991), stated that protein intake for athletes should form 12-15% of total energy consumed. This percentage remains the same for those individuals who are sedentary.

Is Too Much Protein Harmful?

Consuming more protein than your body needs offers no advantages in terms of health or physical performance. Once an optimal level of protein intake has been reached, any excess protein is not converted into muscle and does not improve strength or stamina.

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Protein when eaten in excess of what the body requires represents a burden on the body as it needs to be eliminated. The nitrogen part of protein is excreted and the remainder is converted into glucose. Excess glucose may be used as an immediate energy source or may be converted into glycogen (stored glucose). However, if your diet is also providing adequate amounts of glucose (carbohydrates) glycogen stores may be full - consequently excess glucose may be converted into fat.

Summary of Recommendations for Proteins

1991 UK Department of Health Dietary Reference Values for Food Energy and NutrientsProtein Average Percentage of food Energy

12-15%Sedentary 0.75g protein/Kg body weightEndurance athlete 1.2-1.4g of protein/Kg body weightPower lifter 1.7g of protein/Kg body weight

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VITAMINS AND MINERALS

Vitamins

The term vitamin was derived from "vitamine," a compound word coined in 1912 by the Polish biochemist Kazimierz Funk when working at the Lister Institute of Preventive Medicine. The name is from vital and amine, meaning amine of life, because it was suggested in 1912 that the organic micronutrient food factors that prevent beriberi and perhaps other similar dietary-deficiency diseases might be chemical amines. This proved incorrect for the micronutrient class, and the word was shortened to vitamin.

The main function of vitamins is the regulation or control of chemical reactions within the body. Vitamins are needed in small amounts for growth and normal metabolism. Most vitamins form essential components within enzymes or co enzymes (an organic substance which must be present if an enzyme is to work). Although vitamins in themselves do not release energy they are vital in the process of metabolising (breaking down) other nutrients (fats, carbohydrates and proteins).

A vitamin is an organic compound required by an organism as a vital nutrient in limited amounts. An organic chemical compound (or related set of compounds) is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on the circumstances and on the particular organism. For example, ascorbic acid (vitamin C) is a vitamin for humans, but not for most other animals, and biotin and vitamin D are required in the human diet only in certain circumstances. By convention, the term vitamin does not include other essential nutrients such as dietary minerals, essential fatty acids, or essential amino acids (which are needed in larger amounts than vitamins), nor does it encompass the large number of other nutrients that promote health but are otherwise required less often. Thirteen vitamins are universally recognized at present.

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Vitamins are classified by their biological and chemical activity, not their structure. Thus, each "vitamin" refers to a number of vitamer compounds that all show the biological activity associated with a particular vitamin. Such a set of chemicals is grouped under an alphabetized vitamin "generic descriptor" title, such as "vitamin A", which includes the compounds retinal, retinol, and four known carotenoids. Vitamers by definition are convertible to the active form of the vitamin in the body, and are sometimes inter-convertible to one another, as well.

Vitamins have diverse biochemical functions. Some have hormone-like functions as regulators of mineral metabolism (eg vitamin D), or regulators of cell and tissue growth and differentiation (eg some forms of vitamin A). Others function as antioxidants (eg vitamin E and sometimes vitamin C). The largest number of vitamins (eg B complex vitamins) function as precursors for enzyme cofactors, that help enzymes in their work as catalysts in metabolism. In this role, vitamins may be tightly bound to enzymes as part of prosthetic groups: For example, biotin is part of enzymes involved in making fatty acids. Vitamins may also be less tightly bound to enzyme catalysts as coenzymes, detachable molecules that function to carry chemical groups or electrons between molecules. For example, folic acid carries various forms of carbon group – methyl, formyl, and methylene – in the cell. Although these roles in assisting enzyme-substrate reactions are vitamins' best-known function, the other vitamin functions are equally important.

The body cannot manufacture vitamins, which is why they must be obtained through the diet. An adequate amount of each vitamin is necessary to function optimally. Excess amounts however, have never been proven to improve performance.

Vitamins are classified into two types:

water soluble (B vitamins and vitamin C) fat soluble (A, D, E & K)

The fat soluble vitamins A, D, E and K can be stored in the body, mainly in the liver but also in the adipose (fat) tissue. Consequently they do not need to be consumed each day however, this also means that if eaten in excess they can become toxic.

A deficiency of vitamins can lead to illness, disease and even death. However, deficiencies particularly in the UK are rare. The minimum daily requirements are small and can easily be met by eating a varied diet. Most · foods that are high in fat, carbohydrate and protein also contain vitamins, the richest sources however, are green leafy vegetables.

Below is a table of all the vitamins:

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Vitamin generic

descriptor name

Vitamera chemical

name(s) (list not complete)

Solubility

RDA(male,

age 19–70)

Deficiency disease

Upper Intake Level

(UL/day)

Overdose disease

Food sources

Vitamin A

Retinol, retinal, &4 carotenoidsincluding beta carotene

Fat 900 µg

Night-blindness, Hyperkeratosis, and Keratomalacia

3,000 µg

Hypervitaminosis A

Orange, ripe yellow fruits, leafy vegetables, carrots, pumpkin, squash, spinach, liver

Vitamin B1 Thiamine Water 1.2 mg

Beriberi, Wernicke-Korsakoff syndrome

N/D

Drowsiness or muscle relaxation with large doses.

Pork, oatmeal, brown rice, vegetables, potatoes, liver, eggs

Vitamin B2 Riboflavin Water 1.3 mg Ariboflavinosis N/D

Dairy products, bananas, popcorn, green beans, asparagus

Vitamin B3Niacin, niacinamide

Water 16.0 mg Pellagra 35.0 mg

Liver damage (doses > 2g/day) and other problems

Meat, fish, eggs, many vegetables, mushrooms, tree nuts

Vitamin B5 Pantothenic acid Water 5.0 mg Paresthesia N/D

Diarrhea; possibly nausea and heartburn.

Meat, broccoli, avocados

Vitamin B6

Pyridoxine, pyridoxamine, pyridoxal

Water1.3–1.7 mg

Anemia peripheral neuropathy.

100 mg

Impairment of proprioception, nerve damage (doses > 100 mg/day)

Meat, vegetables, tree nuts, bananas

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Vitamin generic

descriptor name

Vitamera chemical

name(s) (list not complete)

Solubility

RDA(male,

age 19–70)

Deficiency disease

Upper Intake Level

(UL/day)

Overdose disease

Food sources

Vitamin B7 Biotin Water 30.0 µgDermatitis, enteritis

N/D

Raw egg yolk, liver, peanuts, certain vegetables

Vitamin B9Folic acid, folinic acid

Water 400 µg

Megaloblast and Deficiency during pregnancy is associated with birth defects, such as neural tube defects

1,000 µg

May mask symptoms of vitamin B12 deficiency; other effects.

Leafy vegetables, pasta, bread, cereal, liver

Vitamin B12

Cyanocobalamin, hydroxycobalamin, methylcobalamin

Water 2.4 µgMegaloblastic anemia

N/D

Acne-like rash [causality is not conclusively established].

Meat and other animal products

Vitamin C Ascorbic acid Water 90.0 mg Scurvy2,000 mg

Vitamin C megadosage

Many fruits and vegetables, liver

Vitamin D Cholecalciferol Fat 10 µgRickets and Osteomalacia

50 µgHypervitaminosis D

Fish, eggs, liver, mushrooms

Vitamin ETocopherols, tocotrienols

Fat 15.0 mg

Deficiency is very rare; mild hemolytic anemia in newborn infants.

1,000 mg

Increased congestive heart failure seen in one large randomized study.

Many fruits and vegetables

Vitamin Kphylloquinone, menaquinones

Fat 120 µgBleeding diathesis

N/D

Increases coagulation in patients taking warfarin

Leafy green vegetables such as spinach, egg

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Anti-vitamins are chemical compounds that inhibit the absorption or actions of vitamins. For example, avidin is a protein in egg whites that inhibits the absorption of biotin. Pyrithiamine is similar to thiamine, vitamin B1, and inhibits the enzymes that use thiamine. See also anti-nutrients.

Minerals

Dietary minerals (also known as mineral nutrients) are the chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen present in common organic molecules.

Minerals are present in all living cells. They are inorganic substances which make up about 4% of total body weight. Each mineral has a unique role in the body. Some are needed in relatively large amounts for example, sodium, potassium, chloride, calcium, phosphorus and magnesium. Others, such as zinc, iron, selenium and iodine are needed in tiny amounts but are still essential if the body is to function normally.

Minerals in order of abundance in the human body include the seven major minerals calcium, phosphorus, potassium, sulfur, sodium, chlorine, and magnesium. Important "trace" or minor minerals, necessary for mammalian life, include iron, cobalt, copper, zinc, molybdenum, iodine, and selenium.

Over twenty dietary minerals are necessary for mammals. The total number of minerals that are absolutely needed is not known for any organism. Ultra trace amounts of some minerals (eg boron & chromium) are known that clearly have a role but the exact biochemical nature is unknown, and others (eg arsenic & silicon) are suspected to have a role in health, but without proof.

Most minerals that enter into the dietary physiology of organisms consist of simple compounds of chemical elements. Larger aggregates of minerals need to be broken down for absorption. Plants absorb dissolved minerals in soils, which are subsequently picked up by the herbivores that eat them and so on, the minerals move up the food chain. Larger organisms may also consume soil (geophagia) and visit mineral licks to obtain limiting mineral nutrients they are unable to acquire through other components of their diet.

Below is a table of all the minerals:

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Dietary element

RDA/AI (mg)

Description CategoryHigh nutrient density

dietary sourcesInsufficiency Excess

Potassium 4700 mg Quantity

is a systemic electrolyte and is essential in coregulating ATP with sodium.

Legumes, potato skin, tomatoes, bananas, papayas, lentils, dry beans, whole grains, yams, soybeans, spinach, chard, sweet potato, turmeric.

hypokalemia hyperkalemia

Chlorine 2300 mg Quantity

is needed for production of hydrochloric acid in the stomach and in cellular pump functions.

Table salt (sodium chloride) is the main dietary source.

hypochloremia hyperchloremia

Sodium 1500 mg Quantity

is a systemic electrolyte and is essential in coregulating ATP with potassium.

Table salt (sodium chloride, the main source), sea vegetables, milk, and spinach.

hyponatremia hypernatremia

Calcium 1300 mg Quantity

is needed for muscle, heart and digestive system health, builds bone, supports synthesis and function of blood cells.

Dairy products, eggs, canned fish with bones (salmon, sardines), green leafy vegetables, nuts, seeds, tofu, thyme, oregano, dill, cinnamon.

hypocalcaemia hypercalcaemia

Phosphorus 700 mg Quantity

is a component of bones (see apatite), cells, in energy processing and many other functions.

Red meat, dairy foods, fish, poultry, bread, rice, oats. In biological contexts, usually seen as phosphate.

hypophosphatemia hyperphosphatemia

Magnesium 420 mg Quantityis required for processing ATP and for bones.

Raw nuts, soy beans, cocoa mass, spinach, chard, sea vegetables, tomatoes, halibut, beans, ginger, cumin, cloves.

hypomagnesemia,magnesium deficiency

hypermagnesemia

Zinc 11 mg Trace

is pervasive and required for several enzymes such as carboxypeptidase, liver alcohol dehydrogenase, and carbonic anhydrase.

Calf liver, eggs, dry beans, mushrooms, spinach, asparagus, scallops, red meat, green peas, yoghurt, oats, seeds, miso

zinc deficiency zinc toxicity

Iron 18 mg Trace is required for many proteins and enzymes, notably hemoglobin to prevent anemia. Dietary sources include red meat, leafy green vegetables, fish (tuna,

Grains, dry beans, eggs, spinach, chard, turmeric, cumin, parsley, lentils, tofu, asparagus, salad greens, soybeans, shrimp, beans,

anaemia iron overload disorder

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Dietary element

RDA/AI (mg)

Description CategoryHigh nutrient density

dietary sourcesInsufficiency Excess

salmon), eggs, dried fruits, beans, whole grains, and enriched grains.

tomatoes, olives

Manganese 2.3 mg Traceis a cofactor in enzyme functions.

Spelt grain, brown rice, beans, spinach, pineapple, tempeh, rye, soybeans, thyme, raspberries, strawberries, garlic, squash, eggplant, cloves, cinnamon, turmeric

manganese deficiency

manganism

Copper

Main article: Copper in health

0.900 mg Trace

is required component of many redox enzymes, including cytochrome c oxidase.

Mushrooms, spinach, greens, seeds, raw cashews, raw walnuts, tempeh, barley

copper deficiency copper toxicity

Iodine 0.150 mg Trace

is required not only for the synthesis of thyroid hormones, thyroxine and triiodothyronine and to prevent goiter, but also, probably as an antioxidant, for extrathyroidal organs as mammary and salivary glands and for gastric mucosa and immune system (thymus):

Iodine in biology

Sea vegetables, iodized salt, eggs. Alternate but inconsistent sources of iodine: strawberries, mozzarella cheese, yogurt, milk, fish, shellfish.

iodine deficiency iodism

Selenium 0.055 mg Trace

a cofactor essential to activity of antioxidant enzymes like glutathione peroxidase.

Brazil nuts, cold water wild fish (cod, halibut, salmon), tuna, lamb, turkey, calf liver, mustard, mushrooms, barley, cheese, garlic, tofu, seeds

selenium deficiency selenosis

Molybdenum 0.045 mg Trace

the oxidases xanthine oxidase, aldehyde oxidase, and sulfite oxidase

Tomatoes, onions, carrots

molybdenum deficiency

Iron Deficiency

Iron is important as it forms an essential part of haemoglobin (the protein that transports oxygen in the blood stream). If the body is deficient in iron, red blood cell production can

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be affected.

Who is at risk of iron deficiency?

Those who are susceptible to iron deficiency include:

Young children Teenagers Females of childbearing age, including women who are physically active. Pregnancy can also trigger iron deficiency because of the increased iron demand

for both mother and foetus. Women on vegetarian-type diets (iron obtained from plant foods is not as easily

absorbed by the body).

Normally adults take in approximately 5-6mg or iron for each 1000 kcal of food they consume. Therefore, those people who are on a restricted intake (eg dieters) can end up with iron deficiency.

What Are the Symptoms of Anaemia?

Tiredness/ easily fatigued Breathlessness on exertion Pale skin Sore mouth Nail changes Dizziness Insomnia

Lack of appetite

If you are concerned that one of your clients may have anaemia suggest that they seek medical advice. Clients should avoid taking any supplements unless they are under medical supervision.

Excessive iron intakes from supplements can be dangerous - the iron stored in the body can become toxic - it is better to change eating habits so they include more iron-rich foods on a daily basis.

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What Stops the Body Absorbing Iron?

Remind your clients that it is not just 'any old iron' that is important. Animal protein contains haeme-iron, which is more easily absorbed by the body.

The absorption of non-haem iron, (iron from plant sources), is affected by chemicals found in certain foods. These chemicals (which include tannin, mainly found in tea and phytic acid, found in the outer layer of cereals), bind to the iron or make iron insoluble and prevent its absorption into cells.

Vitamin C can enhance iron absorption. So, drinking a glass of orange juice with fortified breakfast cereal or serving beans on toast with tomatoes will help the absorption of non-haeme iron.

The following tips will help with acquiring an adequate iron intake;

Eat lean cuts of red meat, and the dark meat of chicken or turkey 3-4 times per week (animal protein contains haeme-iron which is more easily absorbed).

Choose breads, pastas and cereals that are 'iron-enriched' or 'fortified'. Eat these foods with a source of vitamin C (eg drink orange juice with meals), remember vitamin C aids iron absorption.

Avoid constantly drinking coffee or tea with each meal as they contain substances (tannin) which interfere with iron absorption.

Salt

Salt, also known as table salt, or rock salt, is a crystalline mineral that is composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of ionic salts. It is essential for animal life in small quantities, but is harmful to animals and plants in excess. Salt is one of the oldest, most ubiquitous food seasonings and salting is an important method of food preservation. The taste of salt (saltiness) is one of the basic human tastes.

Salt for human consumption is produced in different forms: unrefined salt (such as sea salt), refined salt (table salt), and iodized salt. It is a crystalline solid, white, pale pink or light gray in color, normally obtained from sea water or rock deposits. Edible rock salts may be slightly grayish in color because of mineral content.

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Chloride and sodium ions, the two major components of salt, are needed by all known living creatures in small quantities. Salt is involved in regulating the water content (fluid balance) of the body. The sodium ion itself is used for electrical signaling in the nervous system. Because of its importance to survival, salt has often been considered a valuable commodity during human history. However, as salt consumption has increased during modern times, scientists have become aware of the health risks associated with high salt intake, including high blood pressure in sensitive individuals. Therefore, some health authorities have recommended limitations of dietary sodium, although others state the risk is minimal for typical western diets.

Acute effects

Too much or too little salt in the diet can lead to muscle cramps, dizziness, or electrolyte disturbance, which can cause neurological problems, or death. Drinking too much water, with insufficient salt intake, puts a person at risk of water intoxication (hyponatremia). Salt is sometimes used as a health aid, such as in treatment of dysautonomia.

Death can occur by ingestion of large amounts of salt in a short time (about 1 g per kg of body weight). Deaths have also resulted from attempted use of salt solutions as emetics, forced salt intake, and accidental confusion of salt with sugar in child food.

Long-term effects

The effect of salt consumption on long term health outcomes is controversial. The effects of salt reduction appears to have an unclear effect on mortality and its effect on morbidity is contentious.

Some associations include:

Stroke and cardiovascular disease. High blood pressure: Evidence shows an association between salt intakes

and blood pressure among different populations and age range in adults. Reduced salt intake also results in a small reduction in blood pressure.

Left ventricular hypertrophy (cardiac enlargement): "Evidence suggests that high salt intake causes left ventricular hypertrophy, a strong risk factor for cardiovascular disease, independently of blood pressure effects." "...there is accumulating evidence that high salt intake predicts left ventricular hypertrophy." Excessive salt (sodium) intake, combined with an inadequate intake of water, can cause hypernatremia. It can exacerbate renal disease.

Oedema: A decrease in salt intake has been suggested to treat edema (fluid retention).

Stomach cancer is associated with high levels of sodium, "but the evidence does not generally relate to foods typically consumed in the UK." However, in Japan, salt consumption is higher.

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The Cochrane Collaboration found that a modest and long term reduction in population salt intake would result in a lower population blood pressure, and a reduction in strokes, heart attacks and heart failure.

In 1994, the British Medical Journal published a randomized double blind placebo controlled study examining 100 Dutch middle-aged and elderly subjects with mild to moderate hypertension. A low sodium, high potassium, high magnesium mineral salt was used at the table and in foods given to the intervention group, with the control group ordinary table salt in their foods and at the table. Over a 24-week period, the researchers found a reduced blood pressure in the intervention group, with mean blood pressure falling by 7.6 mm Hg (systolic) and 3.3 mm Hg (diastolic) in the mineral salt group compared with the control group. However, critics have pointed out that it is possible that some of the subjects may have changed their dietary habits due to many of them being able to distinguish the mineral salt from table salt due to their different taste.

According to The Mayo Clinic and Australian Professor Bruce Neal, the health consequences of ingesting sea salt or regular table salt are the same, as the content of sea salt is still mainly sodium chloride.

Summary of Recommendations for Vitamins and Minerals

1991 UK Department of Health Dietary Reference Values for Food Energy and NutrientsPlenty of fruit and vegetables; at least 5 portions of a variety of fruit andvegetables a dayPregnant women and those women trying for a baby should take 400 microgram (μg, mcg) of folic acid daily until 12th week of pregnancy. In addition to this, they should also eat folate rich foods such as, green vegetables, brown rice and fortified breakfast cereals. Pregnant and breastfeeding women should also take a daily 10mcg supplement of vitamin D.Children under the age of 5 who are not good eaters may need to take a supplement containing vitamins A, D & C. Children who have a good appetite and eat a wide variety of foods, including fruit and vegetables, might not need vitamin drops. Parents who are concerned about their child’s diet should talk to their GP or health visitor for further adviceConsumers should consider taking a daily 10mcg vitamin D supplement if they are of Asian origin, rarely get outdoors or are housebound, wear clothes that cover all your skin when you are outdoors or eat no meat or oily fish.Age Target average salt intake (g/d)

0-6 months Less than 1 7-12 months 1 1 – 3 years 2 4-6 years 3 7-10 years 5 11 years + 6

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FLUID REPLACEMENT

Water

Water is essential, it is second only to oxygen as a substance necessary for life. It makes up approximately 50 -55% of total body weight. Water has several important roles within the body:

• it stabilises body temperature via sweating

• fluid in blood carries nutrients to working muscles and carries away metabolic waste products ·

• fluid in urine helps to eliminate waste products

• it is needed for cells to function

If too little fluid is drunk, or large amounts of fluid are lost via sweating, the body becomes less able to carry out the above tasks. Consequently, performance in any activity will be impaired.

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Proper hydration is essential for exercise performance. During physical activity sweat is produced to help lower body temperature (during hard exercise the body may generate 20 times more heat than at rest). As sweat evaporates it helps to cool the skin and this in turn cools the blood. Any loss of body fluid reduces the ability to circulate blood. Blood flow to the skin decreases and body temperature begins to rise. Performance begins to decline and physical activity becomes increasingly difficult. If the body temperature continues to rise the participant may suffer from heat exhaustion or heat stroke.

An adequate consumption of fluids is obviously the best way to prevent dehydration. A person's water consumption is normally governed by the thirst mechanism, which is regulated by the hypothalamus in the brain. However an individual who is exercising hard and losing a large amount of water through sweat may become dehydrated before feeling thirsty.

Unfortunately, the thirst mechanism is not reliable. By the time the body reacts to thirst, it is already dehydrated. Thirst is triggered by high concentrations of sodium (a part of salt) in the blood. When you sweat, you lose significant amounts of water from your blood. Less water in the blood stream causes it to become more concentrated. Increased concentrations of sodium are then detected by the brain, which in turn stimulates the thirst mechanism.

Two groups of the population who need greater monitoring with regard to fluid intake are young children (who have poorly developed thirst mechanisms) and senior citizens (who tend to be less sensitive to the thirst mechanism). Both these groups should take care to ensure they have an adequate fluid intake, particularly if they participate in exercise.

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How Much Fluid Should You Consume?

The exact amount you should drink depends on how large you are and how much you can comfortably cope with. Individual needs should be determined through trial and error however, there are some general guidelines:

Reduce the risk of chronic dehydration by quenching the thirst – then drinking more, particularly in hot weather or if training hard.

Consume plenty of drinks, ideally water up to 2 hours prior to exercising – the kidneys need approximately 60-90 minutes to process excess fluid.

Drink 1-2 cups of water 5-15 minutes before starting your workout or before competing.

In hot weather, drink as much and as often as you can manage during activity.

Always drink before you are thirsty, by the time your thirst is stimulate you may have lost 3 cups of sweat (approximately 1% of your body weight). A 2% loss of body weight may reduce your ability to exercise by 10-15%.

What Should You Drink?

It does not have to be water per se that is, drunk to meet daily requirements – almost any none-alcoholic liquid will do. However, caffeine has a dehydrating effect therefore caffeinated tea or coffee is recommended for optimal hydration.

Water is often the best fluid for those who wish to exercise. Water empties more quickly from the stomach because it does not need to be digested. Drinks containing high amounts of sugar need to be digested, and therefore the fluid contained within is absorbed more slowly. Consequently these drinks are not as effective as water when it comes replacing the fluid lost during exercise.

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What About Commercial Sports Drinks?

Commercial sports drinks contain small amounts of sugars and minerals called electrolytes (such as sodium and potassium) Al low concentrations this can be speed up water absorption. Electrolytes do not improve performance – they help to get water into the body faster and therefore prevent performance from deteriorating. Unless you are exercising very hard for over an hour in hot conditions they are not necessary.

Hypotonic Drinks are less concentrated than the body's fluids, they are designed to be absorbed more rapidly than water, leading to faster re-hydration

Isotonic Drinks have the same concentration of dissolved particles as body fluids, they will be absorbed at the same speed as water, or faster depending on exercise conditions

Hypertonic Drinks are more concentrated than body fluids and will therefore be absorbed less quickly into your body

How Do You Know If You Are Replacing Fluid Adequately?

The simplest way to tell if you're adequately replacing fluid is to check the colour and quantity of urine. Darker colour urine suggests dehydration. Another way is to weigh yourself before and after exercise. For every pound you lose, you should drink at least 2 cups of fluid.

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Anti-nutrients

Anti-nutrients are natural or synthetic compounds that interfere with the absorption of nutrients.

In most naturally occurring anti-nutrients, the plant contains the compound in order to assure its continued lifecycle. EG grains protect themselves from predators by being armed with toxic proteins in the form of enzyme-blockers and lectins. Grains, which must be able to sprout in an appropriate environment to continue the grain’s lifecycle, contain anti-nutrients. These enzyme-blockers disrupt the predator’s digestive enzymes discouraging the bird or animal from eating further grain meals.

Foods with high concentrations of lectins, such as beans, cereal grains, seeds, nuts, and potatoes, may be harmful if consumed in excess in uncooked or improperly cooked form. Adverse effects may include nutritional deficiencies, and immune (allergic) reactions. Possibly, most effects of lectins are due to gastrointestinal distress through interaction of the lectins with the gut epithelial cells.

Grains, beans and legumes including soy contain enzyme blockers and lectins. Potatoes contain not only enzyme blockers and lectins but also a group of toxins known as glycoalkaloids.

Lectins and enzyme blockers are mostly neutralized by sprouting or fermentation and sometimes the cooking process (cooking however does nothing to alter the toxic effects of the glycoalkaloids in potatoes).

The glycoalkaloids are particularly concentrated in green and injured potatoes which should be avoided and eating raw potatoes is strongly discouraged.

Some enzyme blockers disrupt the body’s natural protein digestive enzymes including the enzyme pepsin in our stomachs, and trypsin and chymotrepsin in our small intestines. Others block the effects of the enzyme amylase for the digestion of starch. With the blocking of these enzyme functions, the digestive process is altered and the absorption and uptake of essential nutrients from our food is disrupted; thus the name anti-nutrients.

Lectins can be responsible for removing protective mucous from tissue, damaging the cell lining of our intestines, stimulating cells to secrete hormones, causing pancreatic enlargement. Lectins may even be responsible for tricking our immune systems into attacking ourselves as seen in the auto-immune diseases like rheumatoid arthritis and lupus.

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One common example is phytic acid, which forms insoluble complexes with calcium, zinc, iron and copper. Some proteins can also be anti-nutrients, such as the trypsin inhibitors and lectins found in legumes. These enzyme inhibitors interfere with digestion. Another particularly widespread form of anti-nutrients are the flavonoids, which are a group of polyphenolic compounds that include tannins. These compounds chelate metals such as iron and zinc and reduce the absorption of these nutrients, but they also inhibit digestive enzymes and may also precipitate proteins.

Anti-nutrients are found at some level in almost all foods for a variety of reasons. However, their levels are reduced in modern crops, probably as an outcome of the process of domestication. Nevertheless, the large fraction of modern diets that come from a few crops, particularly cereals, has raised concerns about the effects of the anti-nutrients in these crops on human health. The possibility now exists to eliminate anti-nutrients entirely using genetic engineering; but, since these compounds may also have beneficial effects, such genetic modifications could make the foods more nutritious but not improve people's health.

Many traditional methods of food preparation such as fermentation, cooking, and malting increase the nutritive quality of plant foods through reducing certain anti-nutrients such as phytic acid, polyphenols, and oxalic acid. Such processing methods are widely-used in societies where cereals and legumes form a major part of the diet. An important example of such processing is the fermentation of cassava to produce cassava flour: this fermentation reduces the levels of both toxins and anti-nutrients in the tuber.

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Food Additives

Food additives are substances added to food to preserve flavor or enhance its taste and appearance. Some additives have been used for centuries; for example, preserving food by pickling (with vinegar), salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines. With the advent of processed foods in the second half of the 20th century, many more additives have been introduced, of both natural and artificial origin.

Numbering

To regulate these additives, and inform consumers, each additive is assigned a unique number, termed as "E numbers", which is used in Europe for all approved additives. This numbering scheme has now been adopted and extended by the Codex Alimentarius Commission to internationally identify all additives, regardless of whether they are approved for use.

E numbers are all prefixed by "E", but countries outside Europe use only the number, whether the additive is approved in Europe or not. For example, acetic acid is written as E260 on products sold in Europe, but is simply known as additive 260 in some countries. Additive 103, alkanet, is not approved for use in Europe so does not have an E number, although it is approved for use in Australia and New Zealand. Since 1987, Australia has had an approved system of labelling for additives in packaged foods. Each food additive has to be named or numbered. The numbers are the same as in Europe, but without the prefix 'E'.

Categories

Food additives can be divided into several groups, although there is some overlap between them.

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Acids

Food acids are added to make flavors "sharper", and also act as preservatives and antioxidants. Common food acids include vinegar, citric acid, tartaric acid, malic acid, fumaric acid, and lactic acid.

Acidity regulators

Acidity regulators are used to change or otherwise control the acidity and alkalinity of foods.

Anticaking agents

Anticaking agents keep powders such as milk powder from caking or sticking.

Antifoaming agents

Antifoaming agents reduce or prevent foaming in foods.

Antioxidants

Antioxidants such as vitamin C act as preservatives by inhibiting the effects of oxygen on food, and can be beneficial to health.

Bulking agents

Bulking agents such as starch are additives that increase the bulk of a food without affecting its taste.

Food coloring

Colorings are added to food to replace colors lost during preparation, or to make food look more attractive.

Colour retention agents

In contrast to colourings, colour retention agents are used to preserve a food's existing color.

Emulsifiers

Emulsifiers allow water and oils to remain mixed together in an emulsion, as in mayonnaise, ice cream, and homogenized milk.

Flavours

Flavours are additives that give food a particular taste or smell, and may be derived from natural ingredients or created artificially.

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Flavour enhancers

Flavour enhancers enhance a food's existing flavors. They may be extracted from natural sources (through distillation, solvent extraction, maceration, among other methods) or created artificially.

Flour treatment agents

Flour treatment agents are added to flour to improve its color or its use in baking.

Glazing agents

Glazing agents provide a shiny appearance or protective coating to foods.

Humectants

Humectants prevent foods from drying out.

Tracer gas

Tracer gas allow for package integrity testing to prevent foods from being exposed to the atmosphere, thus guaranteeing shelf life.

Preservatives

Preservatives prevent or inhibit spoilage of food due to fungi, bacteria, and other microorganisms.

Stabilizers

Stabilizers, thickeners and gelling agents, like agar or pectin (used in jam for example) give foods a firmer texture. While they are not true emulsifiers, they help to stabilize emulsions.

Sweeteners

Sweeteners are added to foods for flavoring. Sweeteners other than sugar are added to keep the food energy (calories) low, or because they have beneficial effects for diabetes mellitus and tooth decay and diarrhea.

Thickeners

Thickeners are substances which, when added to the mixture, increase its viscosity without substantially modifying its other properties.

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Safety

With the increasing use of processed foods since the 19th century, there has been a great increase in the use of food additives of varying levels of safety. This has led to legislation in many countries regulating their use. For example, boric acid was widely used as a food preservative from the 1870s to the 1920s, but was banned after World War I due to its toxicity, as demonstrated in animal and human studies. During World War II, the urgent need for cheap, available food preservatives led to it being used again, but it was finally banned in the 1950s. Such cases led to a general mistrust of food additives, and an application of the precautionary principle led to the conclusion that only additives that are known to be safe should be used in foods. In the USA, this led to the adoption of the Delaney clause, an amendment to the Federal Food, Drug, and Cosmetic Act of 1938, stating that no carcinogenic substances may be used as food additives. However, after the banning of cyclamates in the USA and Britain in 1969, saccharin, the only remaining legal artificial sweetener at the time, was found to cause cancer in rats. Widespread public outcry in the USA, partly communicated to Congress by postage-paid postcards supplied in the packaging of sweetened soft drinks, led to the retention of saccharin despite its violation of the Delaney clause.

In September 2007, research financed by Britain's Food Standards Agency and published online by the British medical journal The Lancet, presented evidence that a mix of additives commonly found in children’s foods increases the mean level of hyperactivity. The team of researchers concluded that "the finding lends strong support for the case that food additives exacerbate hyperactive behaviors (inattention, impulsivity and over activity) at least into middle childhood." That study examined the effect of artificial colors and a sodium benzoate preservative, and found both to be problematic for some children. Further studies are needed to find out whether there are other additives that could have a similar effect, and it is unclear whether some disturbances can also occur in mood and concentration in some adults. In the February 2008 issue of its publication, AAP Grand Rounds, the American Academy of Pediatrics concluded that a low-additive diet is a valid intervention for children with ADHD:

"Although quite complicated, this was a carefully conducted study in which the investigators went to great lengths to eliminate bias and to rigorously measure outcomes. The results are hard to follow and somewhat inconsistent. For many of the assessments there were small but statistically significant differences of measured behaviors in children who consumed the food additives compared with those who did not. In each case increased hyperactive behaviors were associated with consuming the additives. For those comparisons in which no statistically significant differences were found, there was a trend for more hyperactive behaviors associated with the food additive drink in virtually every assessment. Thus, the overall findings of the study are clear and require that even we skeptics, who have long doubted parental claims of the effects of various foods on the behavior of their children, admit we might have been wrong."

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In 2007, Food Standards Australia New Zealand published an official shoppers' guidance with which the concerns of food additives and their labeling are mediated.

There has been significant controversy associated with the risks and benefits of food additives. Some artificial food additives have been linked with cancer, digestive problems, neurological conditions, ADHD, heart disease or obesity. Natural additives may be similarly harmful or be the cause of allergic reactions in certain individuals. For example, safrole was used to flavor root beer until it was shown to be carcinogenic. Due to the application of the Delaney clause, it may not be added to foods, even though it occurs naturally in sassafras and sweet basil.

Extreme caution should be taken with sodium nitrite which is mainly used as a food coloring agent. Sodium nitrite is added to meats to produce an appealing and fresh red color to the consumer. Sodium nitrite can produce cancer causing chemicals such as nitrosamines, and numerous studies have shown a link between nitrite and cancer in humans that consume processed and cured meats.

Blue 1, Blue 2, Red 3, and Yellow 6 are among the food colorings that have been linked to various health risks in animal models. Blue 1 is used to color candy, soft drinks, and pastries and there has been some evidence that it may cause cancer in mice, but studies have not been replicated. Blue 2 can be found in pet food, soft drinks, and pastries, and has shown to cause brain tumors in mice. Red 3, mainly used in cherries for cocktails has been correlated with thyroid tumors in rats. Yellow 6, used in sausages, gelatin, and candy can lead to the attribution of gland and kidney tumors, again in animal models and contains carcinogens, but in minimal amounts. It should be noted that many animal models are poor substitutes for studying carcinogenic effects in humans because the physiology of rabbits, mice and non-human primates can be very different from humans in the relevant biochemical pathways. There has been no scientific consensus on the carcinogenic properties of these agents in humans and studies are still on-going.

In the EU it can take 10 years or more to obtain approval for a new food additive. This includes five years of safety testing, followed by two years for evaluation by the European Food Safety Authority and another three years before the additive receives an EU-wide approval for use in every country in the European Union Apart from testing and analyzing food products during the whole production process to ensure safety and compliance with regulatory standards, trading standards officers (in the UK) protect the public from any illegal use or potentially dangerous mis-use of food additives by performing random testing of food products.

Standardization of its derived products

ISO has published a series of standards regarding the topic and these standards are covered by ICS 67.220.

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Diets

In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, is often implied the use of specific intake of nutrition for health or weight-management reasons (with the two often being related). Although humans are omnivores, each culture and each person holds some food preferences or some food taboos, due to personal tastes or ethical reasons. Individual dietary choices may be more or less healthy.

Proper nutrition requires ingestion and absorption of fibre, vitamins, minerals, and food energy in the form of carbohydrates, proteins, vegetable oils, and fats. Dietary habits and choices play a significant role in quality of life, health and longevity, and can define cultures and play a role in religion.

Religious and cultural dietary choices

Some cultures and religions have restrictions concerning what foods are acceptable in their diet. For example, only Kosher foods are permitted by Judaism, and Halal foods by Islam. Although Buddhists are generally vegetarians, the practice varies and meat-eating may be permitted depending on the sects. In Hinduism, vegetarianism is the ideal, but meat-eating is not banned. Jain are more or less strictly vegetarian.

Dietary choices

Many people choose to forgo food from animal sources to varying degrees (flexitarianism, vegetarianism, veganism, fruitarianism) for health reasons, issues surrounding morality, or to reduce their personal impact on the environment. Raw foodism is another contemporary trend. These diets may require tuning or supplementation to meet ordinary nutritional needs.

Weight management

A particular diet may be chosen to seek weight loss or weight gain. Changing a subject's dietary intake, or "going on a diet", can change the energy balance and increase or decrease the amount of fat stored by the body. Some foods are specifically recommended, or even altered, for conformity to the requirements of a particular diet. These diets are often recommended in conjunction with exercise. Specific weight loss programs can be harmful to health, while others may be beneficial (and can thus be coined as healthy diets). The terms "healthy diet" and "diet for weight management" are often related, as the two promote healthy weight management. Having a healthy diet is a way to prevent health problems, and will provide your body with the right balance of vitamins, minerals, and other nutrients.

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Eating disorders

An eating disorder is a mental disorder that interferes with normal food consumption, defined by abnormal eating habits that may involve either insufficient or excessive diet.

Health

A healthy diet may improve or maintain optimal health. In developed countries, affluence enables unconstrained caloric intake and possibly inappropriate food choices.

It is recommended by many authorities that people maintain a normal weight (limiting consumption of energy-dense foods and sugary drinks), eat plant-based food, limit red and processed meat, and limit alcohol. However, there is no total consensus on what constitutes a healthy diet.

Diet classification table

Food Type Carnivore Omnivore Pescetarian Vegetarian Vegan Raw vegan Islamic Hindu Jewish Paleolithic diet

Fruits and berries

No Yes Yes Yes Yes Yes Yes Yes Yes Yes

Greens No Yes Yes Yes Yes Yes Yes Yes Yes Yes

Vegetables No Yes Yes Yes Yes Yes Yes Yes Yes Yes

Starchy vegetables

No Yes Yes Yes Yes No Yes Yes Yes No

Grains No Yes Yes Yes Yes No Yes Yes Yes No

Poultry Yes Yes No No No No Yes No Yes Yes

Fish (scaled) Yes Yes Yes No No No Yes No Yes Yes

Seafood (non-fish)

Yes Yes Yes No No No Yes No No Yes

Beef Yes Yes No No No No Yes No Yes Yes

Pork Yes Yes No No No No No No No Yes

Eggs Yes Yes Yes Yes No No Yes No Yes Yes

Dairy No Yes Yes Yes No No Yes Yes Yes No

Nuts No Yes Yes Yes Yes Yes Yes Yes Yes Yes

Alcohol No Yes Yes Yes Yes No No No Yes No

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http://en.wikipedia.org/wiki/Alcohol

http://en.wikipedia.org/wiki/Nut_(fruit)

http://en.wikipedia.org/wiki/Dairy

http://en.wikipedia.org/wiki/Egg_(food)

http://en.wikipedia.org/wiki/Pork

http://en.wikipedia.org/wiki/Beef

http://en.wikipedia.org/wiki/Seafood

http://en.wikipedia.org/wiki/Seafood

http://en.wikipedia.org/wiki/Fish

http://en.wikipedia.org/wiki/Poultry

http://en.wikipedia.org/wiki/Cereal

http://en.wikipedia.org/wiki/Leaf_vegetable

http://en.wikipedia.org/wiki/Berry

http://en.wikipedia.org/wiki/Fruit

http://en.wikipedia.org/wiki/Paleolithic_diet

http://en.wikipedia.org/wiki/Kosher

http://en.wikipedia.org/wiki/Diet_in_Hinduism

http://en.wikipedia.org/wiki/Halal

http://en.wikipedia.org/wiki/Raw_vegan

http://en.wikipedia.org/wiki/Vegan

http://en.wikipedia.org/wiki/Vegetarian

http://en.wikipedia.org/wiki/Pescetarian

http://en.wikipedia.org/wiki/Omnivore

http://en.wikipedia.org/wiki/Carnivore


An individual's diet is the sum of food and drink that he or she habitually consumes. Dieting is the practice of attempting to achieve or maintain a certain weight through diet. People's dietary choices are often affected by a variety of factors, including ethical and religious beliefs, clinical need, or a desire to control weight.

Not all diets are considered healthy. Some people follow unhealthy diets through habit, rather than through a conscious choice to eat unhealthily. Terms applied to such eating habits include "junk food diet" and "Western diet". Many diets are considered by clinicians to pose significant health risks and minimal long-term benefit. This is particularly true of "crash" or "fad" diets – short-term weight-loss plans that involve drastic changes to a person's normal eating habits.

Belief-based diets

Some people's dietary choices are influenced by their religious, spiritual or philosophical beliefs.

Buddhist diet: While Buddhism does not have specific dietary rules, some buddhists practice vegetarianism based on a strict interpretation of the first of the Five Precepts.

Edenic diet: A diet based on what Adam and Eve are believed to have consumed in Garden of Eden. Usually either vegetarian or vegan, and based predominantly on fruit.

Hallelujah diet: A form of Christian vegetarianism developed in the 1970s. The creators interpret a verse from the Bible as suggesting that Christians should only consume seed bearing plants and fruits.

Hindu and Jain diets: Followers of Hinduism and Jainism often follow lacto-vegetarian diets, based on the principle of Ahimsa (non-harming).

Islamic dietary laws: Muslims follow a diet consisting solely of food that is halal – permissible under Islamic law. The opposite of halal is haraam, food that is Islamically Impermissible. Haraam substances include alcohol, pork, and any meat from an animal which was not killed through the Islamic method of ritual slaughter (Dhabiha).

I-tal: A set of principles which influences the diet of many members of the Rastafari movement. One principle is that natural foods should be consumed. Some Rastafarians interpret I-tal to advocate vegetarianism or veganism.

Kosher diet: Food permissible under Kashrut, the set of Jewish dietary laws, is said to be Kosher. Some foods and food combinations are non-Kosher, and failure to prepare food in accordance with Kashrut can make otherwise permissible foods non-Kosher.

Word of Wisdom: The name of a section of the Doctrine and Covenants, followed by members of the Latter Day Saint movement. Dietary advice includes only eating meat "in times of winter, or of cold, or famine".

Vegetarian diets

A vegetarian diet is one which excludes meat. Vegetarians also avoid food containing by-products of animal slaughter, such as animal-derived rennet and gelatin.

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Lacto vegetarianism: A vegetarian diet that includes certain types of dairy, but excludes eggs, and foods which contain animal rennet. A common diet among followers of several religions, including Hinduism and Jainism, based on the principle of Ahimsa (non-harming).

Lacto-ovo vegetarianism: A vegetarian diet that includes eggs and dairy. Vegan diet: In addition to the requirements of a vegetarian diet, vegans do not

eat food produced by animals, such as eggs and dairy products.

Semi-vegetarian diets

Flexitarian diet: A predominantly vegetarian diet, in which meat is occasionally consumed.

Kangatarian: A diet originating from Australia. In addition to foods permissible in a vegetarian diet, kangaroo meat is also consumed.

Pescetarian diet: A diet which includes fish but not meat. Plant-based diet: A broad term to describe diets in which animal products do

not form a large proportion of the diet. Under some definitions a plant-based diet is fully vegetarian; under others it is possible to follow a plant-based diet whilst occasionally consuming meat.

Weight control diets

A desire to lose weight is a common motivation to change dietary habits, as is a desire to maintain an existing weight. Many weight loss diets are considered by some to entail varying degrees of health risk, and some are not widely considered to be effective. This is especially true of "crash" or "fad" diets.

Many of the diets listed below could fall into more than one subcategory. Where this is the case, it is noted in that diet's entry.

Low-calorie diets

Body for Life: A calorie-control diet, promoted as part of the 12-week Body for Life program.

Cookie diet: A calorie control diet in which low-fat cookies are eaten to quell hunger, often in place of a meal.

Hacker's diet: A calorie-control diet from The Hacker's Diet by John Walker. The book suggests that the key to reaching and maintaining the desired weight is understanding and carefully monitoring calories consumed and used.

Nutrisystems Diet: The dietary element of the weight-loss plan from Nutrisystem, Inc. Nutrisystem distributes low-calorie meals, with specific ratios of fats, proteins and carbohydrates.

Weight Watchers diet: Foods are assigned points values; dieters can eat any food with a points value provided they stay within their daily points limit.

Very low calorie diets

A very low calorie diet is, Consuming fewer than 800 calories per day. Such diets are normally followed under the supervision of a doctor.

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Low-carbohydrate diets

Atkins diet: A low-carbohydrate diet, populised by nutritionist Robert Atkins in the late-20th and early-21st centuries. Proponents argue that this approach is a more successful way of losing weight than low-calorie diets; critics argue that a low-carb approach poses increased health risks.

Dukan Diet: A multi-step diet based on high protein and limited carbohydrate consumption. It starts with two steps intended to facilitate short term weight loss, followed by two steps intended to consolidate these losses and return to a more balanced long-term diet.

Crash diets

Crash diet and fad diet are general terms. They describe diet plans which involve making extreme, rapid changes to food consumption, but are also as disparaging terms for common eating habits which are considered unhealthy. Both types of diet are often considered to pose health risks. Many of the diets listed here are weight-loss diets which would also fit into other sections of this list. Where this is the case, it will be noted in that diet's entry.

Beverly Hills Diet: An extreme diet which has only fruits in the first days, gradually increasing the selection of foods up to the sixth week.

Cabbage Soup Diet: A low-calorie diet based on heavy consumption of cabbage soup. Considered a fad diet.

Grapefruit diet: A fad diet, intended to facilitate weight loss, in which grapefruit is consumed in large quantities at meal times.

Israeli Army diet: An eight-day diet. Only apples are consumed in the first two days, cheese in the following two days, chicken on days five and six, and salad for the final two days. Despite what the name suggests, the diet is not followed by Israel Defense Forces. It is considered a fad diet.

Junk food diet: A diet largely made up of food considered to be unhealthy, such high-fat or processed foods.

Subway diet: A crash diet in which a person consumes Subway sandwiches in place of higher calorie fast foods. Made famous by former obese student Jared Fogle, who lost 245 pounds after replacing his meals with Subway sandwiches as part of an effort to lose weight.

Western dietary pattern: A diet consisting of food which is most commonly consumed in developed countries. Examples include meat, white bread, milk and puddings. The name is a reference to the Western world.

Detox diets

Detox diets involve either not consuming or attempting to flush out substances that are considered unhelpful or harmful. Examples include restricting food consumption to foods without colourings or preservatives, taking supplements, or drinking large amounts of water. The latter practise in particular has drawn criticism, as drinking significantly more water than recommended levels can cause hyponatremia.

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Juice fasting: A form of detox diet, in which nutrition is obtained solely from fruit and vegetable juices. The health implications of such diets are disputed.

Diets followed for medical reasons

People's dietary choices are sometimes affected by intolerance or allergy to certain types of food. There are also dietary patterns that might be recommended, prescribed or administered by medical professionals for people with specific medical needs.

Best Bet Diet: A diet designed to help prevent or mitigate multiple sclerosis, by avoiding foods with certain types of protein.

Colon Cancer Diet: Calcium, milk and garlic are thought to help prevent colon cancer. Red meat and processed meat may increase risk.

Diabetic diet: An umbrella term for diets recommended to people with diabetes. There is considerable disagreement in the scientific community as to what sort of diet is best for sufferers.

DASH Diet (Dietary Approaches to Stop Hypertension): A recommendation that those with high blood pressure consume large quantities of fruits, vegetables, whole-grains and low fat dairy foods as part of their diet, and avoid sugar sweetened foods, red meat and fats. Promoted by the US Department of Health and Human Services, a United States government organisation.

Elemental diet: A medical, liquid-only diet, in which liquid nutrients are consumed for ease of ingestion.

Elimination diet: A method of identifying foods which cause a person adverse effects, by process of elimination.

Gluten-free diet: A diet which avoids the protein gluten, which is found in barley, rye and wheat. It is a medical treatment for coeliac disease.

o Gluten-free, casein-free diet: A gluten-free diet which also avoids casein, a protein commonly found in milk and cheese.

Ketogenic diet: A high-fat, low-carb diet, in which dietary and body fat is converted into energy. Used as a medical treatment for refractory epilepsy.

Liquid diet: A diet in which only liquids are consumed. May be administered by clinicians for medical reasons, such as after a gastric bypass or to prevent death through starvation from a hunger strike.

Specific Carbohydrate Diet: A diet that aims to restrict the intake of complex carbohydrates such as found in grains and complex sugars. It is promoted as a way of reducing the symptoms of irritable bowel syndrome (IBS), Crohn's disease, ulcerative colitis, coeliac disease and autism.

Other diets

Alkaline diet: The avoidance of relatively acidic foods – foods with low pH levels – such as grains, dairy, meat, sugar, alcohol, caffeine and fungi. Proponents believe such a diet may have health benefits; critics consider the arguments to have no scientific basis.

Blood Type Diet: A diet based on a belief that people's diets should reflect their blood types.

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Dr. Hay diet: Developed by William Howard Hay in the 1920s. Divides foods into separate groups, and suggests that proteins and carbohydrates should not be consumed in the same meal.

Eat-clean diet: Focusses on eating foods without preservatives, and on mixing lean proteins with complex carbohydrates.

Earth Diet: An example of raw foodism; encourages exclusively eating foods in their natural state.

Feingold diet: A diet which attempts to combat hyperactivity by avoiding foods with certain synthetic additives and sweeteners.

Fit for Life diet: The dietary aspect to Fit for Life, a book by Harvey and Marilyn Diamond. Its recommendations include not combining protein and carbohydrates, not drinking water at meal time, and avoiding dairy foods.

Food combining diet: A nutritional approach where certain food types are deliberately consumed together or separately. For instance, some weight control diets suggest that proteins and carbohydrates should not be consumed in the same meal.

F-plan diet: A high-fibre diet, intended to facilitate weight loss. Fruitarian diet: A diet which predominantly consists of raw fruit. Gerson therapy: A form of alternative medicine, the diet is low salt, low fat and

vegetarian, and also involves taking specific supplements. It was developed by Max Gerson, who claimed the therapy could cure cancer and chronic, degenerative diseases. These claims have not been scientifically proven, and the American Cancer Society claims that elements of the therapy have caused serious illness and death.

The Graham Diet: A vegetarian diet which promotes whole-wheat flour and discourages the consumption of stimulants such as alcohol and caffeine. Developed by Sylvester Graham in the 19th century.

Hay diet: A food-combining diet. High-protein diet: A diet in which high quantities of protein are consumed with

the intention of building muscle. Not to be confused with low-carb diets, where the intention is to lose weight by restricting carbohydrates.

High residue diet: A diet in which high quantities of dietary fibre are consumed. High-fiber foods include certain fruits, vegetables, nuts and grains.

Inuit diet: Inuit people traditionally consume food that is fished, hunted or gathered locally; predominantly meat and fish.

Jenny Craig: A weight-loss program from Jenny Craig, Inc. It includes weight counselling among other elements. The dietary aspect involves the consumption of pre-packaged food produced by the company.

Low-carbohydrate diet: A diet in which carbohydrates are avoided, normally with the intention of losing weight. Often involves the consumption of larger amounts of protein, although the diet should not to be confused with high-protein diets.

Low carbon diet: Consuming food which has been produced, prepared and transported with a minimum of associated greenhouse gas emissions. An example of this was explored in the book 100-Mile Diet, in which the authors only consumed food grown within 100 miles of their residence for a year. People who follow this type of diet are sometimes known as locavores.

Low-fat diet Low glycemic index diet

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Low-protein diet Low sodium diet Macrobiotic diet A diet in which processed food is avoided. Common

components include grains, beans and vegetables. Master Cleanse: A form of juice fasting. Medifast Diet: A weight-loss diet based on foods sold by Medifast, Inc. Mediterranean diet: A diet based on habits of some southern European

countries. One of the more distinct features is that olive oil is used as the primary source of fat.

Montignac diet: A weight-loss diet characterised by consuming carbohydrates with a low glycemic index.

Negative calorie diet: A claim by many weight-loss diets that some foods take more calories to digest than they provide, such as celery. The basis for this claim is disputed.

Okinawa diet: A low-calorie diet based on the traditional eating habits of people from the Ryukyu Islands. Okinawans are the longest lived people in the world.

Omnivore: An omnivore consumes both plant and animal-based food. Organic food diet: A diet consisting only of food which is organic – it has not

been produced with modern inputs such as chemical fertilizers, genetic modification, irradiation or food additives.

Paleolithic diet: Can refer either to the eating habits of humans during the Paleolithic era, or of modern dietary plans based on these habits.

Prison loaf: A meal replacement served in some United States prisons to inmates who are not trusted to use cutlery. Its composition varies between institutions and states, but as a replacement for standard food, it is intended to provide inmates with all their dietary needs.

Pritikin Program for Diet and Exercise: A diet which focusses on the consumption of unprocessed food.

Raw foodism: A diet which centres on the consumption of uncooked and unprocessed food. Often associated with a vegetarian diet, although some raw food dieters do consume raw meat.

Scarsdale Medical Diet Shangri-La Diet Slimming World diet Smart For Life Sonoma diet South Beach diet SparkPeople diet Stillman diet Sugar Busters: Focuses on restricting the consumption of refined

carbohydrates, particularly sugars. Swank diet: Focuses on restricting the consumption of saturated fat. Zone diet: A diet in which a person attempts to split calorie intake from

carbohydrates, proteins and fats in a 40:30:30 ratio.

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VEGETARIANISM

Vegetarianism encompasses the practice of following plant-based diets (fruits, vegetables, etc.), with or without the inclusion of dairy products or eggs, and with the exclusion of meat (red meat, poultry, and seafood). Abstention from by-products of animal slaughter, such as animal-derived rennet and gelatin, may also be practiced.

Vegetarianism can be adopted for different reasons. Many object to eating meat out of respect for sentient life. Such ethical motivations have been codified under various religious beliefs, along with the concept of animal rights. Other motivations for vegetarianism include health, political, environmental, cultural, aesthetic or economic. There are varieties of the diet as well: an ovo-vegetarian diet includes eggs but not dairy products, a lacto-vegetarian diet includes dairy products but not eggs, and an ovo-lacto vegetarian diet includes both eggs and dairy products. A vegan, or strict vegetarian, diet excludes all animal products, including eggs, dairy, and honey.

Various packaged or processed foods, including cake, cookies, chocolate and marshmallows, often contain unfamiliar animal ingredients, and may be a special concern for vegetarians due to the likelihood of such additions. Often, products are scrutinized by vegetarians for animal-derived ingredients prior to purchase or consumption. Vegetarians vary in their feelings regarding these ingredients, however. For example, while some vegetarians may be unaware of animal-derived rennet's role in the usual production of cheese and may therefore unknowingly consume the product, other vegetarians may not be bothered by its consumption. The results of a 2009 International survey suggest the standard definition of vegetarianism is different in different nations. Vegetarians in some nations consume more animal products than those in others.

Semi-vegetarian diets consist largely of vegetarian foods, but may include fish or poultry, or sometimes other meats on an infrequent basis. Those with diets containing fish or poultry may define "meat" only as mammalian flesh and may identify with vegetarianism. A pescetarian diet, for example, includes "fish but no meat". The common use association between such diets and vegetarianism has led vegetarian groups such as the Vegetarian Society to state that diets containing these ingredients are not vegetarian, due to fish and birds being animals.

Etymology

The Vegetarian Society, founded in 1847, says that the word "vegetarian" is derived from the Latin word vegetus meaning lively or vigorous. Despite this, the Oxford English Dictionary (OED) and other standard dictionaries state that the word was formed from the term "vegetable" and the suffix "-arian". The OED writes that the word came into general use after the formation of the Vegetarian Society at Ramsgate in 1847, though it offers two examples of usage from 1839 and 1842.

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Varieties of vegetarianism

There are a number of types of vegetarianism, which exclude or include various foods.

Ovo vegetarianism includes eggs but not dairy products. Lacto vegetarianism includes dairy products but not eggs. Ovo-lacto vegetarianism (or lacto-ovo vegetarianism) includes animal/dairy

products such as eggs, milk, and honey. Veganism excludes all animal flesh and animal products, including milk,

honey, and eggs. Raw veganism includes only fresh and uncooked fruit, nuts, seeds, and

vegetables. Vegetables can only be cooked up to a certain temperature. Fruitarianism permits only fruit, nuts, seeds, and other plant matter that can

be gathered without harming the plant. Sattvic diet (also known as yogic diet), a plant based diet which may also

include dairy (not eggs) and honey, but excludes anything from the onion or leek family, red lentils, durian fruit, mushrooms, blue cheeses, fermented foods or sauces, alcoholic drinks and often also excludes coffee, black or green tea, chocolate, nutmeg or any other type of stimulant such as excess sharp spices.

Buddhist vegetarianism (also known as su vegetarianism) excludes all animal products as well as vegetables in the allium family (which have the characteristic aroma of onion and garlic): onion, garlic, scallions, leeks, chives, or shallots.

Jain vegetarianism includes dairy but excludes eggs and honey, as well as root vegetables.

Macrobiotic diets consist mostly of whole grains and beans.

Within the 'ovo-' groups, there are many who refuse to consume fertilized eggs (with balut being an extreme example), however such distinction is typically not specifically addressed.

Some vegetarians also avoid products that may use animal ingredients not included in their labels or which use animal products in their manufacturing; for example, sugars that are whitened with bone char, cheeses that use animal rennet (enzymes from animal stomach lining), gelatin (derived from the collagen inside animals' skin, bones and connective tissue), some cane sugar (but not beet sugar) and apple juice/alcohol clarified with gelatin or crushed shellfish and sturgeon, while other vegetarians are unaware of such ingredients.

Individuals may describe themselves as "vegetarian" while practicing a semi-vegetarian diet, as some dictionary definitions pertaining to vegetarianism vary and include the consumption of fish, while other definitions exclude fish and all animal flesh. In other cases, individuals may describe themselves as "flexitarian". These diets may be followed by those who reduce animal flesh consumed as a way of transitioning to a complete vegetarian diet or for health, environmental, or other reasons. Semi-vegetarian diets include:

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pescetarianism, which includes fish and some other forms of seafood; pollotarianism, which includes poultry; "pollo-pescetarian", which includes poultry and fish, or "white meat" only; macrobiotic diets consisting mostly of whole grains and beans, but may

sometimes include fish.

Semi-vegetarianism is contested by vegetarian groups who state that vegetarianism excludes all animal flesh.

Health benefits and concerns

Scientific endeavors in the area of vegetarianism have shifted from concerns about nutritional adequacy to investigating health benefits and disease prevention. The American Dietetic Association and Dietitians of Canada have stated that at all stages of life, a properly planned vegetarian diet is "healthful, nutritionally adequate, and provides health benefits in the prevention and treatment of certain diseases." {citation needed}Large-scale studies have shown that mortality from ischaemic heart disease was 30% lower among vegetarian men and 20% lower among vegetarian women than in non-vegetarians. Vegetarian diets offer lower levels of saturated fat, cholesterol and animal protein, and higher levels of carbohydrates, fibre, magnesium, potassium, folate, and antioxidants such as vitamins C and E and phytochemicals.

Vegetarians tend to have lower body mass index, lower levels of cholesterol, lower blood pressure, and less incidence of heart disease, hypertension, type 2 diabetes, renal disease, metabolic syndrome, dementias such as Alzheimer’s disease and other disorders. Non-lean red meat, in particular, has been found to be directly associated with increased risk of cancers of the esophagus, liver, colon, and the lungs. Other studies have shown no significant differences between vegetarians and non-vegetarians in mortality from cerebrovascular disease, stomach cancer, colorectal cancer, breast cancer, or prostate cancer. A 2010 study compared a group of vegetarian and meat-eating Seventh Day Adventists in which vegetarians scored lower on depression tests and had better mood profiles. However, vegetarians are more likely to be deficient in vitamin B12, leading to increased incidence of osteoporosis and depression.

The 2010 version of Dietary Guidelines for Americans, a report issued by the U.S. Department of Agriculture and the U.S. Department of Health and Human Services every five years states:

In prospective studies of adults, compared to non-vegetarian eating patterns, vegetarian-style eating patterns have been associated with improved health outcomes—lower levels of obesity, a reduced risk of cardiovascular disease, and lower total mortality. Several clinical trials have documented that vegetarian eating patterns lower blood pressure. On average, vegetarians consume a lower proportion of calories from fat (particularly saturated fatty acids); fewer overall calories; and more fiber, potassium, and vitamin C than do non-vegetarians. Vegetarians generally have a lower body mass index. These characteristics and other lifestyle factors

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associated with a vegetarian diet may contribute to the positive health outcomes that have been identified among vegetarians.

Western vegetarian diets are typically high in carotenoids, but relatively low in omega-3 fatty acids and vitamin B12. Vegans can have particularly low intake of vitamin B and calcium if they do not eat enough items such as collard greens, leafy greens, tempeh and tofu (soy). High levels of dietary fiber, folic acid, vitamins C and E, and magnesium, and low consumption of saturated fat are all considered to be beneficial aspects of a vegetarian diet.

Medical use

In Western medicine, patients are sometimes advised to adhere to a vegetarian diet. Vegetarian diets have been used as a treatment for rheumatoid arthritis, but the evidence is inconclusive whether this is effective. Certain alternative medicines, such as Ayurveda and Siddha, prescribe a vegetarian diet as a normal procedure. Maya Tiwari notes that Ayurveda recommends small portions of meat for some people, though "the rules of hunting and killing the animal, practiced by the native peoples, were very specific and detailed". Now that such methods of hunting and killing are not observed, she does not recommend the use of "any animal meat as food, not even for the Vata types."

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MEDITERRANEAN DIET

The Mediterranean diet is a modern nutritional recommendation inspired by the traditional dietary patterns of Portugal, Spain, southern Italy, southern France, Greece and specifically the Greek island of Crete, and parts of the Middle East.

On November 17, 2010, UNESCO recognized this diet pattern as an Intangible Cultural Heritage of Italy, Greece, Spain and Morocco, thus reinforcing it not only as a fundamental part of their history and background, but also as a great contribution to the world. Despite its name, this diet is not typical of all Mediterranean cuisine. In Northern Italy, for instance, lard and butter are commonly used in cooking, and olive oil is reserved for dressing salads and cooked vegetables. In North Africa, wine is traditionally avoided by Muslims. In both North Africa and the Levant, along with olive oil, sheep's tail fat and rendered butter (samna) are traditional staple fats.

The most commonly understood version of the Mediterranean diet was presented, amongst others, by Dr Walter Willett of Harvard University's School of Public Health from the mid-1990s on, including a book for the general public. Based on "food patterns typical of Crete, much of the rest of Greece, and southern Italy in the early 1960s", this diet, in addition to "regular physical activity," emphasizes "abundant plant foods, fresh fruit as the typical daily dessert, olive oil as the principal source of fat, dairy products (principally cheese and yogurt), and fish and poultry consumed in low to moderate amounts, zero to four eggs consumed weekly, red meat consumed in low amounts, and wine consumed in low to moderate amounts". Total fat in this diet is 25% to 35% of calories, with saturated fat at 8% or less of calories.

The principal aspects of this diet include high olive oil consumption, high consumption of legumes, high consumption of unrefined cereals, high consumption of fruits, high consumption of vegetables, moderate consumption of dairy products (mostly as cheese and yogurt), moderate to high consumption of fish, low consumption of meat and meat products, and moderate wine consumption.

Olive oil is particularly characteristic of the Mediterranean diet. It contains a very high level of monounsaturated fats, most notably oleic acid, which epidemiological studies suggest may be linked to a reduction in coronary heart disease risk. There is also evidence that the antioxidants in olive oil improve cholesterol regulation and LDL cholesterol reduction, and that it has other anti-inflammatory and anti-hypertensive effects.

Health effects

A number of diets have received attention, but the strongest evidence for a beneficial health effect and decreased mortality after switching to a largely plant based diet comes from studies of Mediterranean diet, e.g. from the NIH-AARP Diet and Health Study.

The Mediterranean diet is often cited as beneficial for being low in saturated fat and high in monounsaturated fat and dietary fibre. One of the main explanations is thought to be the health effects of olive oil included in the Mediterranean diet.

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The Mediterranean diet is high in salt content. Foods such as olives, salt-cured cheeses, anchovies, capers, salted fish roe, and salads dressed with extra virgin olive oil all contain high levels of salt.

The inclusion of red wine is considered a factor contributing to health as it contains flavonoids with powerful antioxidant properties.

Mireille Guiliano credits the health effects of the Mediterranean diet to factors such as small portions, daily exercise, and the emphasis on freshness, balance, and pleasure in food.

Dietary factors are only part of the reason for the health benefits enjoyed by certain Mediterranean cultures. A healthy lifestyle (notably a physically active lifestyle or labour) is also beneficial. Environment may also be involved. However, on the population level, i.e. for the population of a whole country or a region, the influence of genetics is rather minimal, because it was shown that the slowly changing habits of Mediterranean populations, from a healthy active lifestyle and Mediterranean diet to a not so healthy, less physically active lifestyle and a diet influenced by the Western pattern diet, significantly increases risk of heart disease. There is an inverse association between adherence to the Mediterranean diet and the incidence of fatal and non fatal heart disease in initially healthy middle aged adults in the Mediterranean region.

A 10-year study published in the Journal of American Medical Association (JAMA) found that adherence to a Mediterranean diet and healthful lifestyle was associated with more than a 50% lowering of early death rates.

The putative benefits of the Mediterranean diet for cardiovascular health are primarily correlative in nature; while they reflect a very real disparity in the geographic incidence of heart disease, identifying the causal determinant of this disparity has proven difficult. The most popular dietary candidate, olive oil, has been undermined by a body of experimental evidence that diets enriched in monounsaturated fats such as olive oil are not atheroprotective when compared to diets enriched in either polyunsaturated or even saturated fats. A recently emerging alternative hypothesis to the Mediterranean diet is that differential exposure to solar ultraviolet radiation accounts for the disparity in cardiovascular health between residents of Mediterranean and more northerly countries. The proposed mechanism is solar UVB-induced synthesis of Vitamin D in the oils of the skin, which has been observed to reduce the incidence of coronary heart disease, and which rapidly diminishes with increasing latitude. Interestingly, residents of the Mediterranean are also observed to have very low rates of skin cancer (which is widely believed to be caused by over-exposure to solar UV radiation); incidence of melanomas in the Mediterranean countries is lower than in Northern Europe and significantly lower than in other hot countries such as Australia and New Zealand. Its been hypothesized that some components of the Mediterranean diet may provide protection against skin cancer.

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Medical research

The Seven Countries Study found that Cretan men had exceptionally low death rates from heart disease, despite moderate to high intake of fat. The Cretan diet is similar to other traditional Mediterranean diets, consisting mostly of olive oil, bread, abundant fruit and vegetables, fish, and a moderate amount of dairy foods and wine.

The Lyon Diet Heart Study set out to mimic the Cretan diet, but adopted a pragmatic approach. Realizing that some of the people in the study (all of whom had survived a first heart attack) would be reluctant to move from butter to olive oil, they used a margarine based on rapeseed (canola) oil. The dietary change also included 20% increases in vitamin C-rich fruit and bread and decreases in processed and red meat. On this diet, mortality from all causes was reduced by 70%. This study was so successful that the ethics committee decided to stop the study prematurely so that the results of the study could be made available to the public immediately.

According to a 2008 study published in the British Medical Journal, the traditional Mediterranean diet provides substantial protection against type 2 diabetes. The study involved over 13 000 graduates from the University of Navarra in Spain with no history of diabetes, who were recruited between December 1999 and November 2007, and whose dietary habits and health were subsequently tracked. Participants initially completed a 136-item food frequency questionnaire designed to measure the entire diet. The questionnaire also included questions on the use of fats and oils, cooking methods and dietary supplements. Every two years participants were sent follow-up questionnaires on diet, lifestyle, risk factors, and medical conditions. New cases of diabetes were confirmed through medical reports. During the follow-up period (median 4.4 years) the researchers from the University of Navarra found that participants who stuck closely to the diet had a lower risk of diabetes. A high adherence to the diet was associated with an 83% relative reduction in the risk of developing diabetes.

A 2008 study published in The New England Journal of Medicine examined the effects of three diets: low-carb, low-fat, and Mediterranean. The study involved 322 participants and lasted for two years. The low-carb and Mediterranean diet resulted in the greatest weight loss, 12 lbs and 10 lbs, respectively. The low-fat diet resulted in a loss of 7 lbs. One caveat of the study is that 86% of the study participants were men. The low-carb and Mediterranean diets produced similar amounts of weight loss in the overall study results and in the men. In the remaining participants who were women, the Mediterranean diet produced 3.8 kg (8.4 lbs) more weight loss on average than the low-carb diet.

A meta-analysis published in the British Medical Journal in 2008 showed that following strictly the Mediterranean diet reduced the risk of dying from cancer and cardiovascular disease as well as the risk of developing Parkinson's and Alzheimer's disease. The results report 9%, 9%, and 6% reduction in overall, cardiovascular, and cancer mortality respectively. Additionally a 13% reduction in incidence of Parkinson's and Alzheimer's diseases is to be expected provided strict adherence to the diet is observed. As well, a 2007 study found that adherence to the Mediterranean diet (MeDi) may affect not only risk for Alzheimer disease (AD) but also subsequent disease course: Higher adherence to the MeDi is associated with

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lower mortality in AD. The gradual reduction in mortality risk for higher MeDi adherence tertiles suggests a possible dose-response effect.

A study published in the British Medical Journal in 2009 showed some components of the Mediterranean diet, such as high vegetable consumption and low meat and meat product consumption, are more significantly associated with low risk of mortality than other components, such as cereal consumption and fish consumption. As part of the European Prospective Investigation into Cancer and Nutrition study, researchers followed more than 23,000 Greek men and women for 8.5 years to see how various aspects of a Mediterranean diet affect mortality. Moderate alcohol consumption, high fruit and nut consumption, and high legume consumption were also associated with lower risk of mortality. Mediterranean Diet, articulated into extensive lifestyles interventions in a clinical follow-up study, improves renal artery circulation, decreasing renal resistive index, even without significant modifications of Insulin Resistance. This is a beneficial effect and modifies the pathophysiology of essential hypertension. Another study (reported on in the news in February 2010) found that the diet may help keep the brain healthy by reducing the frequency of the mini-strokes that can contribute to mental decline. Mediterranean Diet is becoming a comprehensive popular and successful translational paradigm for the promotion of healthier lifestyles.

A 2011 meta-analysis published in the Journal of the American College of Cardiology analyzed the results of 50 studies (35 clinical trials, 2 prospective and 13 cross-sectional) covering about 535,000 people to examine the effect of a Mediterranean diet on metabolic syndrome. The researchers reported that a Mediterranean diet is associated with lower blood pressure, blood sugar, and triglycerides.

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HAY DIET

The Hay Diet is a nutrition method developed by the New York physician William Howard Hay in the 1920s. It claims to work by separating food into three groups: alkaline, acidic, and neutral. (Hay's use of these terms does not completely conform to the scientific use, i.e., the pH of the foods.) Acid foods are not combined with the alkaline ones. Acidic foods are protein rich, such as meat, fish, dairy, etc. Alkaline foods are carbohydrate rich, such as rice, grains and potatoes. It is also known as the food combining diet.

A similar theory, called nutripathy, was developed by Gary A. Martin in the 1970s. Others who have promulgated alkaline-acid diets include Edgar Cayce, D. C. Jarvis, and Robert O. Young.

History

Dr. William Hay contracted Bright's disease (or what modern medicine refers to as Nephritis). Heart-dilated and near death, Dr. Hay began eating only natural foods; his calorie intake dropped and his health improved. Dr. Hay spent the following decade studying naturopathy and food combining to reduce the acid end-product of digestion. He found that fruits and vegetables produce an alkaline end-product when they are fully metabolized, while processed and refined foods left a high acidic environment after digestion. His theories went on to encompass food-combining; whereas incorrect combination would cause even alkaline foods to leave a less desirable acidic digestion end-product.

"Any carbohydrate foods require alkaline conditions for their complete digestion, so must not be combined with acids of any kind, as sour fruits, because the acid will neutralise. Neither should these be combined with a protein of concentrated sort as these protein foods will excite too much hydrochloric acid during their stomach digestion." - Dr. Hay, How to Always Be Well

The Hay System promoted the practice of eating three meals per day with meal one being alkaline foods only, meal two protein foods with salads, vegetables and fruit, and meal three comprising starchy foods with salads, vegetables and sweet fruit. There should be an interval of 4.0 to 4.5 hours between each meal. However, in 1935, Dr. Stewart Baxter showed that the pancreas secretes digestion enzymes simultaneously regardless of whether the food eaten is carbohydrates or protein There is also no evidence to support the notion that acidic and alkaline foods should be eaten separately.

Studies

The food-combining diet has been the subject of one peer-reviewed randomized clinical trial, which found no benefit from the diet in terms of weight loss.

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ATKINS DIET

The Atkins diet, officially called the Atkins Nutritional Approach, is a low-carbohydrate diet created by Robert Atkins from a research paper he read in the Journal of the American Medical Association published by Gordon Azar and Walter Lyons Bloom.

Atkins stated that he used the study to resolve his own overweight condition. He later popularized the method in a series of books, starting with Dr. Atkins' Diet Revolution in 1972. In his second book, Dr. Atkins' New Diet Revolution (2002), he modified parts of the diet but did not alter the original concepts.

Nature of the diet

The Atkins diet involves limited consumption of carbohydrates to switch the body's metabolism from metabolizing glucose as energy over to converting stored body fat to energy. This process, called ketosis, begins when insulin levels are low; in normal humans, insulin is lowest when blood glucose levels are low (mostly before eating). Reduced insulin levels induces lipolysis which consumes fat to produce ketone bodies. On the other hand, caloric carbohydrates (for example, glucose or starch, the latter made of chains of glucose) affect the body by increasing blood sugar after consumption. (In the treatment of diabetes, blood sugar levels are used to determine a patient's daily insulin requirements). Fibre, because of its low digestibility, provides little or no food energy and does not significantly affect glucose and insulin levels.

In his book Dr Atkins' New Diet Revolution, Atkins made the controversial argument that the low-carbohydrate diet produces a metabolic advantage because "burning fat takes more calories so you expend more calories". He cited one study where he estimated this advantage to be 950 calories (4.0 MJ) per day. A review study published in Lancet concluded that there was no such metabolic advantage and dieters were simply eating fewer calories because of boredom. Professor Astrup stated, "The monotony and simplicity of the diet could inhibit appetite and food intake".

The Atkins Diet restricts "net carbs" (digestible carbohydrate grams that affect blood sugar less fiber grams). One effect is a tendency to decrease the onset of hunger, perhaps because of longer duration of digestion (fats and proteins take longer to digest than carbohydrates). Atkins states in his 2002 book New Diet Revolution that hunger is the number one reason why low-fat diets fail and that the Atkins diet is easier because one is allowed to eat as much as one wants.

Net carbohydrates can be calculated from a food source by subtracting fiber and sugar alcohols (which are shown to have a smaller effect on blood sugar levels) from total carbohydrates. Sugar alcohols contain about two calories per gram, and the American Diabetes Association recommends that diabetics count each gram as half a gram of carbohydrate. Fructose (for example, as found in many industrial sweeteners) has four calories per gram but has a very low glycemic index and does not cause insulin production, probably because β cells have low levels of GLUT5. Leptin, an appetite regulating hormone, is however not triggered following

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consumption of fructose. This may for some create an unsatisfying feeling after consumption which might promote binge behavior that culminates in an increased blood triglyceride level arising from fructose conversion by the liver.

Preferred foods in all categories are whole, unprocessed foods with a low glycemic index, although restrictions for low glycemic carbohydrates (black rice, vegetables, etc.) are the same as those for high glycemic carbohydrates (sugar, white bread). Atkins Nutritionals, the company formed to market foods which work with the Atkins Diet, recommends that no more than 20% of calories eaten while on the diet come from saturated fat.

Atkins' book, Atkins Diabetes Revolution, states that, for people whose blood sugar is abnormally high or who have Type 2 diabetes mellitus, the Atkins diet decreases or eliminates the need for drugs to treat these conditions. The Atkins Blood Sugar Control Program (ABSCP) is an individualized approach to weight control and permanent management of the risk factors for diabetes and cardiovascular disease. Nevertheless, the causes of Type 2 diabetes remain obscure, and the Atkins Diet is not accepted in conventional therapy for diabetes.

Ketogenic diet

The induction phase of the Atkins diet is a ketogenic diet. In ketogenic diets there is production of ketones that contribute to the energy production in the Krebs cycle. Ketogenic diets rely on the insulin response to blood glucose. Because ketogenic dieters eat few carbohydrates, there is no glucose that can trigger the insulin response. When there is no glucose-insulin response there are some hormonal changes that cause the stored fat to be used for energy. Blood glucose levels have to decrease to less than 3.58 mmol/L for growth hormone, epinephrine, and glucagon to be released to maintain energy metabolism. In the adipose cells, growth hormone and epinephrine initiate the triacylglycerol to be broken down to fatty acids. These fatty acids go to the liver and muscle where they should be oxidized and give acetyl-CoA that enters the Krebs cycle directly. However, the excess acetyl-CoA in the liver is converted to ketones (ketone bodies), that are transported to other tissues. In these tissues they are converted back into acetyl-CoA in order to enter the Krebs cycle. Glucagon is produced when blood glucose is too low, and it causes the liver to start breaking glycogen into glucose. Since the dieter does not eat any more carbohydrates, there is no glycogen in the liver to be broken down, so the liver converts fats into free fatty acids and ketone bodies, and this process is called ketosis. Because of this, the body is forced to use fats as a primary fuel source.

Main effects

The effects of the Atkins diet remain a subject of much debate. Some studies conclude that the Atkins diet helps prevent cardiovascular disease, lowers the low density lipoprotein (LDL) cholesterol, and increases the amount of HDL, or so-called "good" cholesterol. Some studies suggest that the diet could contribute to osteoporosis and kidney stones. A University of Maryland study, in which test subjects were given calorie increases whenever their weight started to drop, showed higher LDL cholesterol and markers for inflammation.

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Scientific studies

Because of substantial controversy regarding the Atkins Diet and even disagreements in interpreting the results of specific studies it is difficult to objectively summarize the research in a way that reflects scientific consensus. Although there has been some research done throughout the twentieth century, most directly relevant scientific studies, both those that directly analyze the Atkins Diet and those that analyze similar diets, have occurred in the 1990s and early 2000s and, as such, are relatively new. Researchers and other experts have published articles and studies that run the gamut from promoting the safety and efficacy of the diet to questioning its long-term validity to outright condemning it as dangerous. Until recently a significant criticism of the Atkins Diet was that there were no studies that evaluated the effects of Atkins beyond a few months. However, studies are emerging which evaluate low-carbohydrate diets over much longer periods, controlled studies as long as two years and survey studies as long as two decades.

A Swedish prospective study with a follow-up of approximately 10 years came to the conclusion that elderly Swedish men on a carbohydrate-restricted diet (however 40% carbohydrates compared to the Atkins recommended 4%) had very low hazard ratios, with a hazard ratio of 1.2 for all-cause mortality compared to controls and a hazard ratio of 1.4 for cardiovascular mortality.

In addition to research on the efficacy of Atkins and other low-carbohydrate diets, some research has directly addressed other areas of health affected by low-carbohydrate diets. For example, contrary to popular belief that low-carbohydrate diets damage the heart, one study found that women eating low-carbohydrate, high-fat/protein diets had the same or slightly less risk of coronary heart disease, compared to women eating high-carbohydrate, low-fat diets. Other studies have found possible benefits to individuals with diabetes, cancer, and epilepsy. One study comparing two levels of low-carbohydrate diets (ketogenic--the lowest carbohydrate level--and non-ketogenic) found that both had positive effects in terms of insulin sensitivity, weight loss, and fat loss while the ketogenic diet showed slightly higher risks of inflammation and somewhat lower perceived levels of vigor, described as "potentially harmful metabolic and emotional side-effects" (although it should be noted that one of the researchers of this study, Barry Sears, markets The Zone as a competing low-carbohydrate diet).

A 2007 study done at Stanford University Medical School, The A to Z Weight Loss Study, compared the Atkins diet with the Zone, Ornish, and LEARN diets in a randomized group of 311 obese premenopausal women over a period of 12 months. The study found that weight loss was significantly higher for the Atkins diet compared to the other three diets. Secondary factors such as HDL-C, triglyceride levels, and systolic blood pressure were also found to have improved to greater levels compared to the other diets.

A 2012 study done at Boston Children's Hospital compared a very low carbohydrate diet (the Atkins diet) with a low fat, high carbohydrate diet, and a low glycemic index diet. Reduction of the resting metabolic rate as a result of dieting, a key factor in the

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failures of dieting, was the least in the very low carbohydrate diet. In addition, measured total energy expenditure in the patients was the highest in the very low carbohydrate diet, suggesting that a very low carbohydrate diet would be the most likely to produce a sustained weight loss. A possible negative side effect was that C-Reactive Protein levels, a marker for possible future cardiovascular disease, trended somewhat higher in the very low carbohydrate diet.

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F-PLAN DIET

The F-plan is a high fibre diet designed to induce healthy weight loss, created in the 1980s by British author Audrey Eyton, founder of Slimming Magazine, and based on the work of Denis Burkitt. The diet works by restricting the daily intake of calories to less than 1,500 whilst consuming well-above the recommended level of dietary fibre. The fibre has a number of beneficial effects, such as making the dieter feel "full" for much longer than normal, reducing the urge to overeat, and promoting a healthy digestive system.

The disadvantages include excessive flatulence in the first few weeks and having to eat food that is harder work to chew and swallow. Some people also express a dislike of the texture of such a high fibre diet. The dieter will need to consume more water than usual to prevent constipation.

Nevertheless, the diet is very effective when followed faithfully and remains a popular choice of diet, with genuine health benefits.

In 2006 Audrey Eyton published "F2", a revised version of the F-plan written in the light of subsequent medical discoveries, which claims to be faster and more effective and campaigns against low-carbohydrate diets, particularly the Atkins Diet.

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ALKALINE ASH DIET

The term alkaline diet (also known as the alkaline ash diet, alkaline acid diet, acid ash diet, and the acid alkaline diet) describes a group of loosely related diets based on the belief that certain foods can affect the acidity of bodily fluids, including the urine or blood, and can therefore be used to treat or prevent diseases. Acidity is measured by the pH level of the fluid, and can range from 0-14, with a low pH corresponding to an acidic fluid, a high pH corresponding to an alkaline fluid, and a pH level of 7 being neutral.

The relationship between diet and acid-base homeostasis, or the regulation of the acid-base status of the body, has been studied for decades, though the medical applications of this theory have largely focused on changing the acidity of urine. Traditionally, this diet has advocated for avoiding meat, poultry, cheese, and grains in order to make the urine more alkaline (higher pH) in order to change the environment of the urine to prevent recurrent urinary tract infections and kidney stones. However, difficulties in effectively predicting the effects of this diet has led to medications, rather than diet modification, as the preferred method of changing urine pH. The "acid-ash" hypothesis has been considered a risk factor for osteoporosis by various scientific publications, though more recently, the available weight of scientific evidence does not support this hypothesis.

The term "alkaline diet" has also been used by alternative medicine practitioners, with the proposal that such diets treat or prevent cancer, heart disease, low energy levels as well as other illnesses. These claims are not supported by any evidence and make assumptions about how such a diet would work that run counter to current understanding of human physiology.

Diet composition

According to the traditional theory underlying this diet, acid ash is produced by meat, poultry, cheese, fish, eggs, and grains. Alkaline ash is produced by fruits and vegetables, except cranberries, prunes and plums. Since the acid or alkaline ash designation is based on the residue left on combustion rather than the acidity of the food, foods such citrus fruits that are generally considered acidic are actually considered alkaline producing in this diet.

Current hypotheses

More recently, it has been hypothesized that diets high in "acid ash" (acid producing) elements will cause the body to try to buffer (or counteract) any additional acid load in the body by breaking down bone, leading to weaker bones and increased risk for osteoporosis. Conversely, "alkaline ash" (alkaline producing) elements will theoretically decrease the risk of osteoporosis. This theory has been advanced in a Position Statement of the American Dietetic Association in a publication of the U.S. National Academy of Sciences, as well as other scientific publications, which have stated foods high in potassium and magnesium such as fruits and vegetables may decrease the risk of osteoporosis through increased alkaline ash production. This acceptance of the acid-ash hypothesis as a major modifiable risk factor of

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osteoporosis by these publications, however, was largely made without significant critical review by high quality systematic analysis.

Recent systematic reviews have been published which have methodically analyzed the weight of available scientific evidence, and have found no significant evidence to support the acid-ash hypothesis in regards to prevention of osteoporosis. A meta-analysis of studies on the effect of dietary phosphate intake contradicted the expected results under the acid-ash hypothesis with respect to calcium in the urine and bone metabolism. This result suggests use of this diet to prevent calcium loss from bone is not justified. Other meta-analyses which have investigated the effect of total dietary acid intake have also found no evidence that acid intake increases the risk for osteoporosis as would be expected under the acid-ash hypothesis. A review looked at the effects of dairy product intake, which have been hypothesized to increase the acid load of the body through phosphate and protein components. This review found no significant evidence suggesting dairy product intake causes acidosis or increases risk for osteoporosis.

It has also been speculated that this diet may have an effect on muscle wasting, growth hormone metabolism or back pain, though there is no conclusive evidence to confirm these hypotheses.

Alternative medicine

Alternative medicine practitioners have promoted a diet regimen which they call an "alkaline diet" as well, advocating its use in the treatment of various medical conditions including cancer. These claims have been mainly promoted on websites, magazines, direct mail, and books, and have been mainly directed at a lay audience. While it has been proposed that this diet can help increase energy, lose weight, and treat cancer and heart disease, there is no evidence to support any of these claims. This version of the diet, in addition to avoiding meats and other proteins, also advocates avoiding processed foods, white sugar, white flour, and caffeine, and can involve specific exercise and nutritional supplement regimens as well.

Proposed mechanism, effects, and evidence basis

Advocates for alternative uses of an alkaline diet propose that since the normal pH of the blood is slightly alkaline, the goal of diet should be to mirror this by eating a diet that is alkaline producing as well. These advocates propose that diets high in acid producing elements will lead the body in general to become acidic, which can foster disease. This proposed mechanism, in which the diet can significantly change the acidity of the blood, goes against "everything we know about the chemistry of the human body" and has been called a "myth" in a statement by the American Institute for Cancer Research. Unlike the pH level in the urine, a selectively alkaline diet has not been shown to elicit a sustained change in blood pH levels, nor to provide the clinical benefits claimed by its proponents. Because of the body's natural regulatory mechanisms, which do not require a special diet to work, eating an alkaline diet can, at most, change the blood pH minimally and transiently.

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A similar proposal by those advocating this diet suggests that cancer grows in an acidic environment, and that a proper alkaline diet can change the environment of the body to treat cancer. This proposal ignores the fact that while cancer tissue does grow in acidic environment, it is the cancer that creates the acidity. The rapid growth of cancer cells creates the acidic environment; the acidic environment does not create cancer. The proposal also neglects to recognize that it is "virtually impossible" to create a less acidic environment in the body. "Extreme" dietary plans such as this diet have more risks than benefits for patients with cancer.

Other proposed benefits from eating an alkaline diet are likewise not supported by scientific evidence. Although it has been proposed that this diet will increase "energy" or treat cardiovascular disease, there is no evidence to support these assertions. A version of this diet has also been promoted by Robert O. Young as a method of weight loss in his book The pH Miracle. According to the Academy of Nutrition and Dietetics, portions of his diet such as the emphasis on eating green leafy vegetables and exercise would likely be healthy. However, the "obscure theory" on which his diet is based and the reliance on complicated fasting regimens and nutritional supplements means that this diet "is not a healthy way to lose weight." It has also been proposed that acid causes rheumatoid arthritis and osteoarthritis, and that an alkaline diet can be used to treat these conditions. There is no evidence to support this proposal.

Possible disadvantages

Because the alkaline diet promotes excluding certain families of foods, it could result in a less-balanced diet with resulting nutrient deficiencies such as essential fatty acids, phytonutrients, as well as protein and calcium. It has been recommended that patients with a history of kidney disorders or other medical conditions that require frequent physician monitoring such as severe diabetes mellitus should not attempt this diet without physician supervision as you can run the risk of low blood sugar (hypoglycemia) with this type of diet.

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