16-1: The Importance of Food Or “We Are What We Eat”

Four Classes of Organic Compounds The 4 ORGANIC COMPOUNDS that make up most of living organisms are: Carbohydrates Proteins Lipids Nucleic Acids

How do organisms get the organic 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 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 Food 1. Proteins 2. Carbohydrates 3. Fats and Oils 4. Vitamins 5. Minerals 6. Water

Proteins 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

Proteins Found in many foods. Protein-rich foods include: Eggs Meats Fish Milk and cheese Dry Beans, including soybeans Peas Some Nuts From Animals From Plants

Proteins 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.

Proteins 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.)

Carbohydrates Usually the major source of energy in our diet Also provides fiber or bulk Includes: Sugar Starch Fiber

Carbohydrates Found in Grains and Grain Products Cereals Breads Pasta Rice, Barley, Etc. Also in Fruits and Vegetables

How do we measure energy in 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 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) Provide the body with energy Fats are a necessary component of all cells Fat in our bodies cushions and supports vital organs Fat provides our bodies with insulation

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) Sources of lipids in our diets include: Meats Cheeses Nuts Vegetable Oils, Margarines and Butter Many prepared foods including baked goods and fried foods

Vitamins 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.

Vitamins Classified into two types Fat Soluble that can be stored in the body’s fat – A, D, E and K Water 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

Vitamins 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

Vitamins 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 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 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 (B 3 ) deficiency Beriberi – Thiamine (B 1 ) deficiency

B Vitamins There are 8 known B vitamins B 1 - Thiamine B 2 - Riboflavin B 3 - Niacin (Nicotinic Acid) B 6 – Pyridoxine B 12 – Cobalamin Folic Acid Pantothenic Acid Biotin

Minerals 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

Minerals Iron – needed for oxygen transport (part of the hemoglobin molecule) Not enough causes anemia Calcium – vital for normal cell function and a major component of bones and teeth Not enough can lead to osteoporosis Phosphorus – an important part of DNA, RNA and ATP (an energy transferring molecule); part of bones

Minerals Potassium, magnesium and sodium– needed for muscle and nerve function Iodine – needed by thyroid Not enough results in goiter formation Sodium and chloride – water balance Too much can contribute to high blood pressure Fluorine – part of bones and teeth Helps prevent cavities

Minerals Other essential minerals include: Zinc Selenium (poisonous if too much) Copper Manganese Chromium Molybdenum Sulfur

Minerals Others that may be essential include: Boron Nickel Silicon Tin Vanadium

Water Needed because: Our bodies are 65% water All the chemical reactions in our bodies occur in water Water carries nutrients throughout our bodies (blood is 90% water) Water helps maintain correct body temperature

Water 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 liters per day(8-10 cups) to maintain hydration.