Chapter 7 (part 1): ProteinsFoods: Fall 2013

Protein: The main Idea Very important in the diet. Contribute to growth and development. Help the body repair itself. Found in many foods:

Meat Poultry Fish Eggs Dairy Products Beans Peas Nuts Vegetables Grain products

The Structure of Proteins Make up 1/5th of your body’s total weight. Part of every cell, all tissues, and organs. Very complex molecules. Made up of amino acids Amino acids can link together in many different

ways. 22 different amino acids have been identified. When combined amino acids form many

different shapes. Shape determines function of the amino acid.

Protein Digestion Digestion of protein begins in the stomach. The stomach acid changes the shape of the

protein. Then each molecule is broken down into

individual amino acids. The amino acids are then absorbed in the

bloodstream. Upon reaching the cells amino acids can be

used to make protein for specific purposes.

Complete and Incomplete Proteins Your body can make many amino acids for itself,

but not all the amino acids it needs. Essential Amino Acids = amino acids that your

body needs but cannot provide. You must get these through foods.

Complete Protein = foods from animal sources that have all of the needed amino acids

Incomplete Protein = foods from plant sources that do not have all of the essential amino acids.

When your body is lacking essential amino acids it cannot build the proteins you need.

Why we need Protein Growth and maintenance – new cells are

needed for growth. Hair, eyes, teeth, skin, muscles, and bones are made up of proteins.

Enzymes – help with chemical reactions in cells Hormones - chemical messengers that help

regulate conditions in the body. Antibodies – fight invaders and sickness. Made

only when needed. Fluid balance – Helps regulate cell health by

keeping a balance

How munch protein do we need? Experts recommend 10-30% of your calories

should be from proteins. Larger people need more protein than smaller

people. During certain periods of a person’s life you

may need more. Pregnant and breast feeding women Infants Children Teens

Excess Protein Too much can be harmful. Excess is broken down and stored as fat. Healthy people should not need

supplements. Should get all of the proteins and amino

acids you need by eating a variety of food.

Lack of Protein Is a serious problem in 3rd world countries. Protein Energy Malnutrition (PEM) – is a

leading form of malnutrition in the world. Children are especially affected. With PEM loose weight and don’t grow

properly. Can even die of starvation. Can also affect those with eating disorders

or drug/alcohol addiction.