2 utilization of nutrients

8/6/2019 2 Utilization of Nutrients

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Utilization of Nutrients


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Utilization of Nutrients

The body uses three processes to

utilize nutrients

1. Digestion2. Absorption

3. Metabolism


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Digestion

Process by which the body breaks food

down into smaller parts, changes the

food chemically and moves the foodthrough the digestive system

Two types of digestive action

Mechanical digestion

Chemical digestion


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Digestion

Mechanical digestion

Food is broken up by the teeth

Moved through digestive tract by peristalsis, a

rhythmic, wavelike motion of the muscles Chemical digestion

Food is mixed with digestive juices secreted bythe mouth, stomach, small intestine and

pancreas Juices contain enzymes that break down the food

chemically so nutrients can be absorbed into theblood


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Absorption

Process where blood capillaries pick up

the digested nutrients

Nutrients carried by circulatory system toevery body cell

Most absorption occurs in the small

intestine

Water, salts and some vitamins are

absorbed in large intestine


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Processes of

Digestion and Absorption

See page 233

1. Mouth: Teeth and tongue beginmechanical digestion by breaking apartfood

2. Salivary glands: Begin chemicaldigestion as salivary amylase begins to

change starch to maltose3. Esophagus: Peristalsis and gravity

move food along


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Processes of


4. Stomach: Hydrochloric acid prepares

the gastric area for enzyme action.

Pepsin breaks down proteins andLipase acts on emulsified fats

5. Liver: Produces bile

6. Gallbladder: Stores bile and releases it

into small intestine to emulsify fats


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Processes of


7. Pancreas: Enzymes are released into the

small intestine. Pancreatic amylase breaks

down starch. Lipase breaks down fats.

Pancreatic proteases break down proteins

8. Small intestine: Produces enzymes, prepare

foods for absorption, food is further broken

down for absorption by the body. Most

absorption of nutrients takes place here.


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Processes of


9. Large intestine: Absorbs water and

some other nutrients, collects food

residue for excretion


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Metabolism

Process in which nutrients are used by

cells for building tissue, providing energy

or regulating various functions

Nutrients are combined with oxygen and

energy and heat are released

Energy is required for voluntary work as

well as involuntary work


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Metabolism

Basal metabolic rate (BMR) rate atwhich body uses energy just formaintaining its own tissue, without doing

any voluntary work Body needs energy continually

Stores nutrients for future use

Uses stored nutrients to provide energywhen food intake is not adequate for energyneeds


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Measuring Food Energy

Foods vary in the amount of energy theycontain

When body metabolizes nutrients toprovide energy, heat is also released

Measurement of the amount of heatproduced during metabolism is way energycontent of food is measured

Heat measured by a unit called a kilocalorie(kcal) or just calorie


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Measuring Food Energy

Number of kilocalories or calories in a

certain food is known as that foods caloric

value

Carbs and proteins provide four calories pergram

Fat provides nine calories per gram

Vitamins, minerals and water do not provide any

calories


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Individuals Caloric Requirement

Number of kilocalories or calories needed by

the body during a 24-hour period

Varies from person to person depending on

activity, age, size, sex, physical condition andclimate

Usually amount of physical activity or exercise

is main factor determining caloric

requirements, because energy used must be

replaced


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Individuals Caloric Requirement

To gain weight

Decrease activity

AND Increase caloric intake

To lose weight

Increase activity

AND

Decrease caloric intake


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One Pound

One pound of body fat equals about

3,500 calories


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One Pound

To lose one pound you must have adecrease of 3,500 calories

Consume 3,500 fewer calories

Increase exercise to use 3,500 calories

To gain one pound you must have anincrease of 3,500 calories

Consume 3,500 more calories Decrease exercise to conserve 3,500

calories


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To Maintain Weight

General guideline is that a person should

consume 15 calories per pound of body

weight per day

Ex. Person weighing 120 pounds needs

1,800 calories per day to stay at same

weight (120 X 15 = 1,800)


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To Lose Weight

Person can decrease required calories

by 500 per day

Person needing 1,800 could consume1,300 per day

500 calories X 7 days = 3,500 calories =

1 pound

Person would lose 1 pound per week


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To Gain Weight

Person can increase calories by 500 per

day

Person needing 1,800 could consume2,300 per day

500 calories X 7 days = 3,500 calories =

1 pound

Person would gain 1 pound per week


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Weight Loss and Gain

Increasing or decreasing exercise along

with controlling caloric intake is essential

Slow steady gain or loss of 1 to 2 poundsper week is an efficient and safe form of

weight control


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Maintenance of Good Nutrition

Good nutrition is the best way of

achieving and maintaining good health

Accomplished by eating a balanced dietin which all of the required nutrients are

included in the correct amounts

5 major food groups

Grains, vegetables, fruits, milk, meat and

beans


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Grains

Eat 6 oz every day

At least half should be whole grains Vegetables

Eat 2 cups every day

Eat a variety of dark-green, orange and

other brightly colored veggies


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Fruits

Eat 2 cups every day

Eat a variety of fresh, frozen, canned or

dried fruit (with no sugar added) Go easy of fruit juices

Milk

Eat 3 cups every day Choose low-fat or fat-free milk, yogurt and

cheese


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Meat & Beans

Eat 5 oz every day

Choose low-fat or lean meats and poultry Bake, broil or grill

Eat a variety of fish, beans, nuts and seeds


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7 Guidelines for

Good Eating Habits

1. Eat a variety of foods

Choose different foods from each of the

food groups

Adjust number and size of portions based

on body weight and nutritional needs

Provides wide variety of nutrients required

for good health


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7 Guidelines for

Good Eating Habits

2. Maintain healthy weight

Determine proper body weight

Maintain this weight by proper eating habits and

exercise

3. Choose a diet low in fat, saturated fat and

cholesterol

Eat lean meat, poultry without skin, fish and low-

fat dairy products

Use fats and oils sparingly and limit fried foods


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7 Guidelines for

Good Eating Habits

4. Choose a diet with plenty ofvegetables, fruits and grain products

5. Use sugars in moderation

Limit cookies, candy, cakes and soft drinks

Brush and floss teeth after eating sweetfoods

6. Use salt and sodium in moderation Flavor foods with herbs and spices

Reduce the amount of salty foods


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7 Guidelines for

Good Eating Habits

7. If alcohol is consumed, it should be inmoderation

Should be avoided by pregnant

women, individuals usingmedications, children andadolescents

Should not be used by individualsdriving or engaging in an activityrequiring attention or skill


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Food Habits

Food habits also affect nutrition

Food habits can be based on cultural or

religious beliefs Different cultures and races have certain

food preferences

Some religions require certain dietary

restrictions

See page 237


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Food Habits

Unusual habits are not necessarily bad and

should be evaluated using the major five food

groups as a guide

When habits do require changing in order toimprove nutrition, person making suggestions

must use tack, patience and imagination

Many food habits are formed during youth and

changing them is a difficult and slow process

2 utilization of nutrients

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