FOOD & NUTRITION

Section 38-1Yummy!

Biology 392

Do you know…?

• How many days can you survive without food?• How many days …….without water?• What important nutrient are vegetarians at

risk of missing in their diet?• Is it OK to exceed the recommended amount

of vitamin supplements?

Why do we need food?

• ENERGY • BUILDING NEW MOLECULES– Proteins– Cell membrane– DNA

Nutrition

Definition The study of food and its effects on the body

Measured in CALORIES amount of heat energy needed to raise the temp. of 1 gm(1mL) of water by 1 degree Celsius

1 Calorie = 1 kilocalorie = 1000 calories

You need about 2200 C (♀) to 2800 C (♂) per day

NUTRIENTS

• Your body can extract energy & nutrients from almost any type of food

6 Major Nutrients include: Water Carbohydrates

Vitamins Proteins Minerals Fats (lipids)

WATER

• The most important nutrient• Every cell in the body needs water to

complete many of the body’s processes and chemical reactions

• Water loss causes problems in all body systems

CARBOHYDRATES*

Major source of Energy2 Forms

SIMPLE• Ex: simple sugars– Fruits, honey, sugar cane

• Mono- & di-saccharides

COMPLEX• Ex: Starches– Grains, potatoes,

vegetables

• Ex: Cellulose/Fiber– Lettuce, bran, whole

grain breads– Cannot be broken down,

but important for moving food efficiently.

FATSFUNCTION: Manufacture cell membranes, produce

certain hormones, store energy

2 FORMS• Saturated contains only single bonds– Ex: butter, lard, other animal fats– Solid at Room Temp

• Unsaturated 1 or more double or triple bonds– Ex: Vegetable oils– Liquid at Room Temp

PROTEINS• FUNCTION: Provides body with material for

growth & repair Make up parts of muscles, skin & organsAre enzymes!

• FORMS: 20 common amino acids– Body can naturally produce only 12– Diet must supply other 8• Called ESSENTIAL amino acids

VITAMINS• DEFINITION Organic molecules that are

needed by the body to help perform important chemical reactions

• FUNCTIONS see pg 974• 14 Essential Vitamins • FORMS 2– Fat- Soluble (A,D,E,K) stored in fatty tissues– Water-Soluble (C,B) cannot be stored

MINERALS• DEFINITION Inorganic nutrients the body

needs, usually in small amounts– Found in periodic table

• FUNCTION see page 975– Examples: Ca (bones); Fe (needed for

hemoglobin); Mg (normal function of nerves and muscles)

• Lost in sweat, urine and other wastes.

Summary Questions1. What are the 6 nutrients needed by the

body?2. What would happen if you did not eat enough

carbs & fats?3. Vegetarians may sometimes take dietary

supplements. What, specifically, might they be missing in their meatless diets?

4. You ate a lot of oranges last week for a nice, healthy dose of vitamin C. Must you eat an orange today? Why?

How do you know what to eat?

• Nutritionists have analyzed how much of each nutrient you need and what foods contain the combinations of each.

• This info is compiled in the “food pyramid”

Old Food Pyramid

New Food Pyramid

General Dietary Recommendations:

· 3 to 5 servings of vegetables · 2 to 4 servings of fruits · 2 to 3 servings of milk, yogurt & cheese · 6 to 11 servings of bread, cereal, rice, & pasta · 2 to 3 servings of meat, poultry, fish, dry

beans, eggs & nuts · Use fats, oils & sweets sparingly

Just what is “One Serving”?

Milk products group: · 1 cup about 8 oz. of milk or yogurt · 2 slices of cheese, 1/8" thick (1½ oz.) · 2 cups of cottage cheese · 1½ cups of ice milk, ice cream or frozen yogurt

Meat group: · 2 oz. to 3 oz. of cooked lean meat, poultry, or

fish · 2 eggs · 7 oz. tofu · 1 cup cooked legumes or dried beans or peas · 4 tablespoons peanut butter · 1/2 cup nuts or seeds

Vegetables: · 1/2 cup cooked vegetables · 1/2 cup raw chopped vegetables · 1 cup raw leafy vegetables · 1/2 to 3/4 cup vegetable juice

Fruits: · 1 whole medium fruit (about 1 cup) · 1/4 cup dried fruit · 1/2 cup canned fruit · 1/2 to 3/4 cup fruit juice

Bread and Cereals: · 1 slice bread · 1 medium muffin · 1/2 hot dog bun or hamburger bun · 1/2 bagel or english muffin · 4 small crackers · 1 tortilla · 1 cup cold cereal · 1/2 cup cooked cereal · 1/2 cup rice · 1/2 cup pasta