16-1: The Importance of Food16-1: The Importance of FoodOr “We Are What We Eat”

Four Classes of Organic CompoundsFour Classes of Organic Compounds

The 4 ORGANIC COMPOUNDS that make up most of living organisms are:

CarbohydratesProteinsLipidsNucleic Acids

How do organisms get the organic How do organisms get the organic compounds that they need?compounds that they need?

They can make some of them. Plants make all the organic compounds

they need. They must take in inorganic

compounds that they use to make organic compounds.

They must eat some of them. Animals must consume most of the

organic compounds they use. Many are digested (broken down) into

their components and then assembled into new compounds.

Our FocusOur Focus

We will focus our studies on: What humans obtain from the food they eat What different nutrients are needed for in

our bodies

Later we will investigate the food pyramid, the digestion and absorption of food and maintaining a healthy weight.

The Six Basic Nutrients in FoodThe Six Basic Nutrients in Food

1. Proteins2. Carbohydrates3. Fats and Oils4. Vitamins5. Minerals6. Water

ProteinsProteins

Used for growth and repair of body tissues

Used as enzymes to regulate chemical processes in your cells

Used as antibodies to fight off infection

Used for the production of hormones that regulate the physiology of your body

ProteinsProteins

Found in many foods. Protein-rich foods include:

EggsMeatsFishMilk and cheese Dry Beans, including soybeansPeasSome Nuts

From Animals

From Plants

ProteinsProteins

Proteins from animal sources are the most complete – complete proteins contain all the amino acids your body needs to build the proteins it needs.

The egg is considered the most complete protein for us to eat.

ProteinsProteins

Foods from plant sources contain less complete proteins

Most people can still get all the protein they need from plant sources if they choose from the legume group (beans, peas, peanuts, etc.)

CarbohydratesCarbohydrates

Usually the major source of energy in our diet

Also provides fiber or bulk Includes:

SugarStarchFiber

CarbohydratesCarbohydrates

Found in Grains and Grain ProductsCerealsBreadsPastaRice, Barley, Etc.

Also in Fruits and Vegetables

How do we measure energy in How do we measure energy in food?food?

The amount of energy that food provides is measured in Calories.

A food Calorie is defined as the amount of energy needed to raise 1 kg of water by 1°C. (equal to 1,000 calories in physical science)

How do we measure energy in How do we measure energy in food?food?

Sugar and starch provide 4 Calories of energy per gram.

Fiber, which is not digested, does not provide any calories.

Although protein is not primarily eaten to provide energy, if the body does use it for energy it also provides 4 Calories per gram.

Fats and Oils (Lipids)Fats and Oils (Lipids)

Provide the body with energyFats are a necessary component of all

cellsFat in our bodies cushions and

supports vital organsFat provides our bodies with insulation

Fats and Oils (Lipids)Fats and Oils (Lipids)

Lipids supply over twice as much energy per gram than either protein or carbohydrates do (9 Calories per gram)

Mono- and Poly- unsaturated fats are believed to be more healthy for us to consume

Fats and Oils (Lipids)Fats and Oils (Lipids)

Sources of lipids in our diets include:MeatsCheesesNutsVegetable Oils, Margarines and ButterMany prepared foods including baked

goods and fried foods

VitaminsVitamins

A vitamin is any of the organic compounds required by the body in small amounts for metabolism, to protect health and for proper growth in children.

There are 13 well-identified vitamins; they are not chemically related.

They generally act as catalysts in combination with proteins/enzymes.

VitaminsVitamins

Classified into two typesFat Soluble that can be stored in the

body’s fat – A, D, E and KWater Soluble that cannot be stored and

need to be eaten frequently (daily if possible)– the 8 B vitamins and Vit. C

The only one that can be made by our bodies is Vitamin D

VitaminsVitamins

Each vitamin performs one or more specific functions in our bodies. Some things they are important for include: Red blood cell formation Vision Blood Clotting Amino Acid, energy, and carbohydrate

metabolism Formation of bones, teeth and connective tissue

VitaminsVitamins

Vitamins come from a variety of food sources, for example:Vit. A (β carotene) – Yellow and green

vegetable, egg yolks, etc.Vit. C – citrus fruits, tomatoes, etc.

Many foods are good sources of one or more vitamins, especially vegetables, whole grains and meats

Vitamin DeficienciesVitamin Deficiencies

Diseases can result from a lack of specific vitamins:Scurvy – lack of Vit. C, used to be a

problem for sailors who did not get fresh fruits for long periods of time

Rickets – lack of Vit. D causing deformed bones and bowlegs (Not usually a problem in the tropics; why not?)

Vitamin DeficienciesVitamin Deficiencies

Diseases can result from a lack of specific vitamins:Blindness – Lack of Vitamin A is still a

major cause of blindness of children in poor countries

Pellagra – Niacin (B3) deficiency

Beriberi – Thiamine (B1) deficiency

B VitaminsB Vitamins

There are 8 known B vitaminsB1- Thiamine

B2- Riboflavin

B3 - Niacin (Nicotinic Acid)

B6 – Pyridoxine

B12 – CobalaminFolic AcidPantothenic AcidBiotin

MineralsMinerals

Minute amounts of metallic elements that are vital for the healthy growth of teeth and bones

Also function in enzyme action, muscle contraction, nerve reaction, oxygen transport, and blood clotting

MineralsMinerals

Iron – needed for oxygen transport (part of the hemoglobin molecule)

Not enough causes anemiaCalcium – vital for normal cell function

and a major component of bones and teeth

Not enough can lead to osteoporosisPhosphorus – an important part of

DNA, RNA and ATP (an energy transferring molecule); part of bones

MineralsMinerals

Potassium, magnesium and sodium– needed for muscle and nerve function

Iodine – needed by thyroid Not enough results in goiter formation

Sodium and chloride – water balanceToo much can contribute to high blood

pressure

Fluorine – part of bones and teethHelps prevent cavities

MineralsMinerals

Other essential minerals include:ZincSelenium (poisonous if too much)CopperManganeseChromiumMolybdenumSulfur

MineralsMinerals

Others that may be essential include:BoronNickelSiliconTinVanadium

WaterWater

Needed because:Our bodies are 65% waterAll the chemical reactions in our

bodies occur in waterWater carries nutrients throughout

our bodies (blood is 90% water)Water helps maintain correct body

temperature

WaterWater

Water comes both from what we drink and from what we eat.

Fruits and vegetables often contain 80-90% water and meat has about 50%.

We need about 2.4-2.8 liters per day(8-10 cups) to maintain hydration.