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!