Chapter 7 Proteins

and Fats

Protein Protein helps your body grow and repair itself. Found in animal products, including meat, poultry, fish, eggs, and dairy products.

Also, in plant foods, especially dry beans and peas, nuts, vegetables, and grain products.

Structure of Proteins Proteins are part of every cell in your body. They are made of amino acids.

Amino acid is a molecule that combines with other amino acid molecules to make proteins.

20 different amino acids are found in protein foods. Different proteins perform specialized tasks.

Some combine an form hemoglobin. Hemoglobin: is a protein that transports oxygen un the

blood to all the cells in your body.

Protein Digestion How does protein in your food become protein in

your body?Your body breaks down protein into amino acids. Amino acids combine into proteins your body needs. Amino acids are absorbed into the bloodstream and

sent to the cells to make new proteins.

Complete and Incomplete Your body makes some, but

not all, amino acids for itself. Essential amino acid: an

amino acid that your body needs but cannot make

Complete protein: A food that contains all 9 essential amino acids. Meat, poultry, fish, eggs, milk,

and soy Incomplete protein: food

that lacks one or more of the essential amino acids. Mixture of them to complete all

needed amino acids.

Need for Protein Proteins have countless roles in the body. Here are

the 5 most important:1. Growth and maintenance

Constantly broken down and replaced 2. Enzymes

Chemical reactions take place in every cell in your body. Enzymes make this possible.

3. Hormones Chemical messengers that help regulate the body.

4. Antibodies Play a role in the immune system

5. Fluid Balance

How much do you need?!

Teens should get 10 to 30 percent of their calories from proteins.

Adults should get 10 to 35 percent Example:

Teens calorie requirement is 2800. What is the range of calories that this teen needs from protein. (2800 x .10 = 280) (2800 x .30 = 840)

Preotin has 4 calories per gram Divide those each by 4 to determine the amount in grams. (70-210g)

Excess Protein Eating to much protein can be harmful to your

body. Hard on the digestive systemBroken down and stored by the body as fat

Weight gain

No need for supplements with proteins or amino acids.

Inadequate Protein Protein-energy malnutrition (PEM) occurs

Most common form of malnutrition in the world. Children do not grow properlyDie of starvationEating disorders and addictions

Protein Food Choices Plant sources have less fat and more fiber than

animal foodsUsually cost less too!

VarietyMeat with plant foods Just plant foodsEtc. Page. 90 examples

The Lipid Family

•Lipids are a family of chemical compounds found in every cell, both in foods and in the human body. •Two types of lipids:

•Triglyceride: is a basic fat molecule

•Main component of fatty tissue.

•Sterols: lipids found in cell membranes

•Cholesterol

FatsFats are greasy substances, with solid or liquid, that

will not dissolve in water. Liquid fats are called oils.

High fat foods are usually high in calories Examples: butter, margarine, oils, cream, fried foods,

ice cream, nuts, egg yolks, and whole milk. Visible Fats:

Fats that can be seen (marbling in meat products.) Invisible Fats:

Cannot be seen and is a part of the chemical composition of the food. Egg yolks.

Why Are Fats Needed?

Fat helps the body absorb vitamins A, D, E, and K. Body fat serves as an energy reserveCushions and protects vital organsProvides warmth Fat is a component of cell membranesHelp you feel full longer after eating (long digestion time)Enhances the flavor of most foods Add moisture and tenderness, or crispiness to foods

Structure of Fats Fatty Acid: is the basic building block of fats.

Takes three of to make a triglyceride. Saturated Fatty Acid: contains all the hydrogen

it can chemically hold. Usually solid at room temperature (butter, meat fat)

Unsaturated fatty acid: are missing hydrogen unitsMonounsaturated: missing one Polyunsaturated: missing two or more

Usually liquid at room temperature (oils)

Essential Fatty Acids

Your body makes some, but not all fats for itself. Essential fatty acid: is a fatty

acid your body needs but does not produce for itself, it must be consumed. Omega-3 : lowers the risk of

heart disease. Found in: sardines, salmon,

trout, herring, flax seeds, kiwi, walnuts, and pumpkin seeds

Fat digestion Fats are mainly digested in the small intestine.

Gall bladder release bile which helps to break down the fatty acid.

Fatty acids are absorbed into the bloodstream- travel to the liver and tissues that need them.

Lipoprotein: fat-protein unitChemical packages

Cholesterol Cholesterol: is a fatlike substance in cells that is

needed for many body processes.Helps digest fat, build cells, and make vitamin D and

hormones.

Cholesterol circulates in the blood in two forms:LDL: low-density lipoprotein; takes cholesterol from

the liver to wherever it is needed in the body. LDL is known as the “bad” cholesterol. (Build up in artery walls)

HDL: High-density lipoproteins; picks up excess cholesterol and takes it back to the liver. HDL is known as the “good” cholesterol.

Diet Affects Cholesterol Saturated Fat

Raise the level of LDL cholesterol Meat, Poultry skin, whole-milk, tropical oils (coconut oil)

Polyunsaturated FatHelp lower cholesterol levels if used in place of

saturated fats.Vegetable oils, corn oil, soybean oil

Monounsaturated FatLower levels of LDL and Raise levels of HDL

Olives, avocados, nuts, peanut oil, and canola oil.

Trans FatsHydrogenation: turns vegetable oils into solids.

The missing hydrogen is added to the unsaturated fats, which increases saturation. Shortening and most margarines Longer shelf-life and extra flavor

Trans-Fats: hydrogenation forms fatty acids Increase LDL levels and lower HDL levels

Salad dressings, snack food, baked goods, fast foods, and crackers

How many calories of fat?

Most Americans eat TOO much fat; especially saturated fat. Increase of heart disease, and cancer

You NEED fat in your diet, just in moderation.Teens need 25-35 percent of their caloric intakeAdults need 20-35 percent of their caloric intake

Controlling Fat

Eat plenty of fruits, vegetables, and whole-grain productsChoose fat-free or low-fat milkRemove skin from chicken and turkeyChose lean cuts of meat- trim fat and drain greaseWatch portion sizesChose fish or lean poultry over red meatLimit fried foodsAvoid trans-fats