1. Proteins: The body’s Building Blocks
Chapter 7
Proteins:
The body’s Building Blocks

2. What is protein
Protein is an energy-yielding nutrient composed of carbon, hydrogen, oxygen, and nitrogen. The presence of nitrogen is what makes it different from carbohydrate and fat.
Amino acids are the building blocks of protein molecules.

3. Some protein facts
There are 20 different amino acids. They combine in different sequences to form different types of protein.
The body probably has at least types of protein. Each type performs a specific job. The number of amino acids and the order in which they are linked determines the type of protein formed.
Think of the 20 amino acids like the letters of the alphabet.

4. DNA Deoxyribonucleic acid
DNA is found in the nucleus of every cell and provides instruction for how the amino acids will form the protein in your body.

5. Denaturation
This is the process by which protein molecules take on a new shape and new characteristics. Heat, acids, bases, and alcohol are among the factors that can denature proteins.
Raw egg + heat = cooked egg
(liquid) (solid)

6. Types of amino acids
You need all 20 types of amino acids for good health. The good news is your body can synthesize 11 of them from other amino acids. These are the nonessential amino acids
The 9 amino acids your body can’t make are called the essential amino acids and you must get them from the food you eat.

7. Protein in the body
When you eat a protein food, stomach acids denature the proteins. This makes it easier for enzymes in the stomach to begin breaking down large protein molecules into smaller pieces. As the smaller pieces move along the GI tract, other enzymes break them into single amino acids which are then absorbed into the bloodstream.

8. Function of protein Build and maintain tissues
Make important compounds
Regulate mineral and fluid balance
Maintain acid-base balance
Carry vital substances
Provide energy

9. Food sources of protein
Most people meet their protein needs by eating both animal and plant food sources.
Animal flesh is by far the richest source of protein. Other sources of animal protein include;
Eggs
Milk
Cheese
Yogurt
Ice-cream

10. Plant sources of protein
A plentiful supply of protein is available from plant sources.
Grains
Nuts
Seeds
Legumes (peanuts, lentils, chickpeas, soybeans)

11. Protein Quality
Complete proteins come from animal sources. This means all the essential amino acids humans need are present in the proteins.
Incomplete proteins come from plants and are missing or short in one or more of the essential amino acids.
Your body needs the right balance of all 20 amino acids to build tissues and other compounds.

12. Complementary Proteins
Combining incomplete proteins can give all the essential amino acids required for proper function of the body. Proteins working together this way are called complementary proteins.

13. How much protein do you need?
The RDA for males years old is 52 grams per day. The RDA for females in the same age range is 46 grams per day.
To meet the RDA you will need to get between 10 and 35% of your calories from protein.

14. Athlete’s protein needs
People who exercise occasionally do not need extra protein.
Well trained athletes do need a little more protein to build muscle and supply energy.
The range for protein needs falls somewhere from 10 – 25% of their total calories.

15. Meeting the protein RDA
The simplest way to meet your protein need is to follow the Food guide and get the recommend number of servings dairy and meats/alternatives.
Try to limit the number of choices that contain saturated fats.

16. Too little or too much
Not enough protein can be a problem, but so can too much protein.
The risk of too much protein is;
Liver and kidney problems – creates extra work for the kidneys excreting nitrogen waste. (urea)
Calcium loss
Excess body fat