Unit 12Useful Facts about

Sugars, Starches, and Fiber

Key Concepts and Facts Simple sugars, starches, and dietary fiber Carbohydrates have half the calories of

fat Tooth decay is related to high sugar

intake Poor diets are related to high sugar intake Fiber benefits health

The Carbohydrates The Major source of energy for people of the

world Main component of staples – bread, pasta, rice,

cassava, and beans We Americans consume 50% of total calories

as “carbs.” (Japanese, over 60%) Carbohydrate family has three types

– Simple sugars– Complex carbohydrates (“starch”)– Fiber (ie Cellulose)

…………………………………………………………………BBC, 03/12/2007

Staple Foods Food (200 calories) Protein(gm) Carb(gm) Fat(gm)

Fiber(gm)

Whole wheat bread 10 40 3 6 Brown rice 4 42 3 3 Corn tortilla 4 43 4 3 Cassava 3 47 0.5 0.2 Potato (with skin) 6.3 55 0.3 4 Lentils 14 35 0 12 Pintos 13 35 1 10 Soybeans 18 17 11 6

Pork shoulder 14 0 16 ?

Cassava

Native to South America

Staple Food of700 million people

Most important cropin Africa

Carbohydrate Recommendations

The RDA:– Minimum amount required to provide adequate

glucose for the brain– Set at 130 g/day (~ 420 kcalories)

The Range of Healthy Intakes:– Set at 45% to 65% of energy– No more than 10% of energy should come from

added refined sugars

Synthesis of Glucose and Starch

4-16

Simple Sugar Facts Simple sugars are small molecules Two types: monosaccharides and disaccharides Monosaccharides:

– Glucose (“blood sugar”)– Fructose (“fruit sugar”)– Galactose

Disaccharides consist of two linked molecules– Sucrose is a glucose and a fructose– Maltose is a glucose and a glucose– Lactose is a glucose and a galactose

Simple Carbohydrates Monosaccharides

Simple Carbohydrates

Disaccharides

4-13

Synthesis of Sucrose

Simple Sugar Facts Disaccharides are broken into

monosaccharides during digestion Only glucose, fructose, and galactose are

absorbed into bloodstream High-fructose corn syrup and alcohol sugars

are also simple sugars Most simple sugars have a sweet taste

Glucose Used for energy Fructose and galactose converted to glucose The liver and muscles store glucose as the

polysaccharide glycogen Glycogen: chains of

linked glucose units

Glucose When body needs energy, glycogen makes

glucose available Glucose can also be made from amino acids and

the glycerol of fats Cells require glucose as an energy source

Thiamin, Riboflavin, & NiacinB-1 B-2 B-3

These water-soluble

"B vitamins" are used in reactions that capture and release the energy in carbohydrates.

Each of these also has its own unique functions in the body.

Where’s the Sugar?

Simple sugars are in fruits and some vegetables

Besides milk, animal products have no sugars

Where’s the Sugar? Americans consume 84

grams of added sugar per day, about 17% of the average caloric intake

Sugar consumption up 23% in past 30 years

Biggest source for many is soft drinks

Simple sugars are in fruits and some vegetables

Besides milk, animal products have no sugars

Added Sugars

Sugar is added to food during food processing or preparation

Nutrition labels list total amount of sugar per serving Nutrition labels contain information on total sugars

per serving and do not distinguish between sugars naturally present in foods and added sugars

Ingredient labels: All simple sugars must be lumped together under “sweeteners” followed by a parenthetical list itemizing each type in order of weight

What’s So Bad about Sugar? Foods with simple sugars

are poor sources of nutrients

Simple sugars provide only calories

Many foods high in sugars are also high in fat

Diets often insufficient in vitamins and minerals when high sugar intake

Sugar causes tooth decay

Baby Bottle Caries

From having bottle

with sugar for hours every day and

night

Babies need to be off

the bottle when they

have their first birthday

Carbohydrates and Teeth Sugar and tooth decay related Decay declined during WW I and II Rebounded when sugar became available Highest rates where sugar added to foods Simple sugars come from starchy foods Some countries have campaigns about

cavity-promoting foods

Sugar Fiction and Fact Does sugar cause

– violent and criminal behavior?– produce diabetes?– cause hyperactivity in children?

Sugar actually:– ____________ kids’ activity level – makes adults sleepy– reduces appetite in the short-term

Artificial sweetener facts

Why artificial sweeteners? – unwanted calories in simple sugars– the connection of sucrose with tooth decay– sugar substitute for people with diabetes– sugar shortages

All provided incentives for developing sugar substitutes

Artificial sweetener facts

Artificial sweeteners in many prepared foods None provide many calories, promote tooth

decay or raise blood glucose levels None provide the taste qualities of sucrose Do they help with weight loss? Research results both support and refute a role

for artificial sugars in weight loss

Saccharin

Saccharin was first artificial sweetener developed, in the late 1800s

300 times sweeter than sucrose

Helped relieve sugar shortages during World Wars I and II

Aspartame Aspartame is 200 times sweeter than sucrose Used in 4000 products worldwide, soft drinks,

whipped toppings, jellies, cereals, puddings, medicines

Products carry a label warning people with phenylketonuria (PKU) and others with liver conditions about phenylalanine

PKU folks can’t use phenylalanine so it accumulates in blood

Is Aspartame Safe? Safe level defined as 50 mg/kg body weight per

day in U.S. and 40 mg/kg body weight per day in Canada

U.S. limit equals 20 aspartame-sweetened soft drinks or 55 desserts per day

Average intake from 2 to 10 mg per day, safely low

Problems with headaches, dizziness, or anxiety from small amounts reported by consumers but not confirmed in studies

Sucralose Non-caloric sweetener from sucrose, safe and

600 times sweeter than sucrose Does not leave a bitter aftertaste Known as “Splenda” on product labels Used in hot and cold food products, soft drinks,

baked goods, frosting, pudding, and chewing gum

Safest choice for children and pregnant women

Complex Carbohydrate Facts

Starches, glycogen, and cellulose are complex carbohydrates - polysaccharides

Grains, potatoes, dried beans, and corn contain starch and cellulose, so are complex carbohydrate sources

Little glycogen in animal products Remember, all carbohydrates have 4 calories

per gram

Complex Carbohydrates Oligosaccharides

Polysaccharides

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Carbohydrates: Polysaccharides

Starch, cellulose & glycogen

Why Whole Grains? More protein, vitamins and minerals than refined grains More fiber than refined grain foods Reduce the risk of heart disease and some types of cancer

Bran

Endosperm

Germ

Dietary Fiber Facts Fiber intake in U.S. below the amount

recommended People can get recommended amount from whole-

grain breads, high-fiber cereal, dried beans and adequate vegetables and fruits daily

Amounts in food are the same cooked or raw Fast foods are poor sources of fiber

Types of Fiber Classification of edible fibers is based on

chemical characteristics Natural foods contain insoluble and soluble fibers Fiber is not digested by human digestive

enzymes Fibers are also classified as

– dietary fiber (naturally in the food)– functional fiber (extracted, then added)– total fiber

Types of Fiber Soluble Fiber

– Slows glucose absorption– Reduces fat and cholesterol absorption– Combine chemically with water– Found naturally in oats, barley, fruits, – Can be natural or added to foods– Soluble fiber supplements may reduce

problems of irritable bowel syndrome: diarrhea, constipation and abdominal discomfort

Insoluble Fiber Increases stool bulk, softens stool and

shortens transit time through the intestinal tract

Sources include – Whole grain foods– Wheat and corn bran – Seeds and nuts – Potato skins– Zucchini, cauliflower and green beans

Types of Fiber Functional fibers –processed fibers-- have

beneficial functions in the body-- most are soluble fibers so– reduce post-meal rises in blood glucose levels– prevent constipation– may decrease symptoms of irritable bowel syndrome– decrease fat and cholesterol absorption

Functional fiber is produced to fortify foods Psyllium, pectin, gels, and seed and plant gums,

are functional fibers

Fiber: Add it Up

What can you eat in One day to consume Recommended fiber?

See page 12-12 and table A-1

Men: 38 gm Women: 25 gm

Be Cautious When too much fiber is added too quickly High fiber diets cause diarrhea, bloating,

and gas Bacteria in intestines use fiber and excrete

gas Adding fiber gradually prevents side effects Fluid intake should increase with dietary

fiber

We will not cover

Glycemic Index

Glycemic Load

Hypoglycemia

yet

TheEnd