Chapter 2 Nutritional Needs Nutrition Food Science

Chapter 2 Nutritional

NeedsNutrition Food Science

FoodsProvide the nutrients

needed for good health

NUTRIENT

Chemical substance in food that helps maintain the body

NUTRITION

The study of how the body uses nutrients in the foods you eat

Malnutrition

A lack of the right proportions of nutrients over an extended period.

NUTRIENTS Over 50 needed for good health All help build & maintain cells &

tissue Regulate bodily processes -

breathing No single food provides all

nutrients

The Six Main Nutrients Carbohydrates Fats Proteins Vitamins Minerals Water

Sources of Calories Carbohydrates & Proteins = 4

calories / gm Fat = 9 calories / gm 30% from fat 60% from carbohydrates 10% from proteins

Carbohydrates Body’s main source of energy!!!

2 main types of CarbsSIMPLE Carbohydrates

Glucose Fructose Note: any word that Galactose ends in “ose” is a Sucrose type of sugar Lactose maltose

Complex Carbohydrates Made from many glucose sugar

units that are bonded together.

Starch is the most abundant carbohydrate in the diet

It is the storage form of energy in plants

Functions Of CarbsProvide energyHelp body digest fatsAllow body to use proteins for

growth & maintenance instead of energy

Fiber…

Helps prevent heart disease Lower cholesterol Helps speed food through the body Help dilute carcinogens in food Need 25 (f) – 38 (m) grams daily

Too Much / Too Little Carbohydrate

Deficient… Body uses protein as energy Constipation

Excess Weight gain Tooth & gum decay from acid produced

by bacteria

Function of Fats Promote healthy skin

and normal cell growth Carry vitamins ADE&K

to wherever needed Provide a reserve

supply of energy Act as a cushion to

protect your heart, liver, and other vital organs

Fats add flavor They digest slowly -

so they help you feel full longer

Too much fat can increase the risk of heart disease and cancer

Saturated Fats Come from Animals Are solid at room temperature

Fat Fat and More Fat! Many fats are hidden in

our foods Foods high in fat

Butter Margarine Oils Cream Sour Cream Salad Dressing Fried Foods Baked Goods Chocolate

Unsaturated Fats Come from plants Liquid at room Temperature

Olive oil Corn oil Vegetable oil

“Good Fats”

Cholesterol Is a fat-like substance present in all cells that is needed

for many body processes Adults manufacture all the cholesterol they need in the

liver LDL-takes cholesterol from liver to wherever it’s needed in the

body BUT if too much is circulating the excess amounts of cholesterol can build up in artery walls! “BAD cholesterol”

HDL-picks up excess cholesterol and takes it back to the liver keeping it from causing harm. “GOOD cholesterol”

Proteins made of small units called

amino acids 22 known amino acids

9 essential – body does not make them

11 non-essential – body can make them

Complete Proteins: Supply all 9 essential amino acids – animal foods

Incomplete proteins: lack one or more essential amino acids- plant foods

Proteins Provide energy Help body grow and repair worn out and

damaged parts Hair, eyes, skin, muscles, and bones are made of

proteins Help regulate body functions High protein foods: meat, poultry, fish, eggs,

and dairy products, dry beans, peas, peanuts, veggies and grains

Too Much / Too Little Protein Excess amounts are broken down and

stored in the body as fat!! Deficiency: Called PEM (Protein –energy

Malnutrition) Includes fatigue, weight loss, diarrhea, infections & stunted growth

Types of Vitamins Water-soluble - dissolve in water vitamin C and B vitamins

Fat-soluble - absorbed and transported by fat (vitamins A,D,E, and K)

Vitamins Organic substances needed in

small amounts for:

*Normal growth

*Maintenance

*Reproduction Help keep your body’s tissues

healthy and systems working properly

Antioxidents Substances that protect body cells and the

immune system from harmful chemicals in the air, certain foods, and tobacco smoke.

Minerals Inorganic substances that

make up 4% of your body Most minerals become a

part of your body such as teeth and bones

Macrominerals: Calcium Sodium Phosphorous Potassium Magnesium Chlorine

Microminerals Needed in small amounts (trace elements)

IronZincIodineFlourine

Electrolytes: minerals that work together to maintain the body’s fluid balance (potassium, sodium, and chloride)

Trace Minerals: minerals needed in very small amounts (iron, zinc, copper, iodine, and selenium)

Where do I get Minerals?? Eat plenty of

calcium rich foods Meat, poultry, fish Nuts Whole Grains Green Veggies Dry beans, peas,

lentils

WATER The most critical nutrient to survival!!! People can live without food for 40 days but

only 3 without water!!! Water exists in ALL body cells!! After helping break foods down into nutrients

water carries the nutrients to the cells that need them

What does water do for your body??

breaks the nutrients down into usable forms –helps your joints stay lubricated, your skin soft, and your mind alert

filters out impurities and gets rid of waste products

Keeps body temperature normal!!

How much is enough??? The body uses 2-3

quarts of water a day!!! If lost fluid isn’t replaced a person can become dehydrated

You need 8 cups (2L) of water a day

Most fruits and veggies contain water!

End of Part I

How your body uses foodDIGESTION!!!

The process of breaking down food into usable nutrients. It takes place in the digestive system…..But how???

Let’s start with your food!!!

Movement of Food Through the System

• Mouth: Seconds • Esophagus: Seconds

• Stomach: Up to 3 ½ hours • Small Intestine: Minutes • Large Intestine: Hours

We will start with your food, so get ready!!!

Digestion begins in the …..

Mouth!! Just smelling and seeing food, or even thinking about it can start saliva flowing in your mouth!

Saliva is the first to break down the foods chemically

Food is also broken down physically as your teeth grind it into tiny pieces

Chewing food is very important!!

Next it moves to your….. Esophagus!!! a long tube connecting

your mouth to the stomach

Peristalsis forces food into the stomach

The stomach holds up to 4 cups of food! Juices in the stomach churn food into a substance called “chyme”.

From the stomach…… Chyme is released into the small intestine a little

at a time. The small intestine is a long, winding tube between the stomach and the large intestine.

When fully broken down carbohydrates are turned into a simple sugar called

GLUCOSE- which is the body’s basic fuel supply!

Fats are changed into fatty acids

Proteins are broken down into amino acids

Vitamins and Minerals do not need to be broken down- they are ready just as they are!

Using the Nutrients…. Once food has been broken down, digestion is

complete! BUT- your body must absorb the nutrients and

take them to where they can be used or stored Nutrients are absorbed into the blood stream.

Most absorption takes place in the small intestine. After absorption, some material is left. (mainly

fiber) This material is moved into the large intestine also called the colon. The colon removes water, potassium, and sodium.

The Remainder is stored in the rectum until elimination!