1. Chapter Four: Proteins and Amino Acids
Explain how the chemical structure of proteins differs from the other energy nutrients
Identify and describe the multiple functions of protein in the body
Explain the difference between essential and non-essential amino acids
Describe the concept of nitrogen balance

2. Proteins cntd.
Describe conditions associated with either positive or negative nitrogen balance
Describe causes and characteristics of marasmus and kwashiorkor
Explain what makes a protein complete and identify sources of them
Explain the types of vegetarian diets

3. What do you already know?
Proteins in Review
Energy provided: 4 kcal per gram
12-15% of calories per day
Sources in the Food Guide Pyramid
Bread, Cereal, Rice and Pasta Group
Vegetable Group
Milk, Yogurt and Cheese Group
Meat and Meat Alternates Group

4. Chemical View of Protein
Contains same elements as other energy nutrients (carbon, hydrogen and oxygen) plus nitrogen
Made up of building blocks called amino acids (20 amino acids)
Essential amino acids must be supplied in foods (9 are essential)
Non-essential am. acids—body can make

5. Nutritional Role of Proteins
Primary function is to Build, Maintain, and Repair the Body — not to provide energy
Enzymes: catalysts that facilitate chemical reactions
Anabolic—build body compounds
Catabolic—dismantle body compounds
Example—digestive enzymes

6. Nutritional Roles cntd.
Fluid and Electrolyte Balance
Help maintain distribution of fluids in the body
Proteins are hydrophilic—water loving
Acid-Base Balance
Controls blood pH (acidity or alkalinity)
Release or bind hydrogen ions

7. Protein roles cntd. Antibodies Hormones
Formed from protein
Maintains resistance to disease
Hormones
Messenger molecules
Examples are insulin and thyroxin
Transport—carry other nutrients, e.g. oxygen, lipids, vitamins and minerals

8. Protein Roles cntd.
Nitrogen Balance—maintenance of same amount of protein in body tissues
Positive Balance—nitrogen in > nitrogen out
Growing children
Pregnant woman
Negative Balance—nitrogen in < nitrogen out
Fasting or starvation
Severe traumas—burns, tissue loss

9. Protein Roles cntd. Zero balance
Nitrogen in = nitrogen out
Normal daily functioning
Measured by sample of body tissue or urine

10. Protein Deficiency Marasmus Kwashiorkor: (Red hair)
Energy deficiency common in young children ages 6-18 months
Food is low in kcalories and protein
Kwashiorkor: (Red hair)
Protein deficiency common in children after age two—after weaning
Symptoms: edema, distended abdomen and orange hair

11. Proteins in Foods Complete Proteins: Incomplete Proteins:
Contain all essential amino acids
Sources are animal foods with the exception of gelatin
Incomplete Proteins:
Limited in amounts or number of essential amino acids
Sources are grains, vegetables and legumes

12. Protein Sparing
Carbohydrate needed to spare protein from being used for energy
If protein is used for energy it is deaminized—nitrogen is removed—and the C, H, and O are used for energy
Low carbohydrate diets are not recommended for this reason

13. Vegetarian Diets
Vegetarianism: rely mostly on non animal foods for their diet
Levels of Vegetarianism
Lacto-vegetarians—milk only
Lacto-ova—milk and eggs
Vegans—exclude all animal products
Advantages:
Easier to maintain desired weight
Lower cholesterol and higher fiber foods
Lower rates of colon cancer and heart disease
Better digestion—low fat and high fiber

14. Vegetarian Pyramid

15. Vegetarianism cntd. Nutritional concerns
Vitamin B12 only found in animal products
Vitamin D mainly available in milk and animal fats
Iron and Zinc are not as available in non-animal sources

16. TEST Questions
1. Proteins are chemically different from carbohydrates and fat because they also contain:
A. Phosphorus
B. Sodium
C. Iron
D. Nitrogen

17. Test Questions 4. The basic building blocks of protein are:
a. glucose units
b. amino acids
c. side chains
d. saturated bonds