Proteins, Amino Acids
• About 20% of total body weight = protein
• Contain -

Amino Acids =
• Smallest building blocks of proteins
• 20 different amino acids:
• -
• -

Essential Amino Acids =
• Body can NOT make them at all or
• can NOT make them in sufficient quantities for normal health

Non-essential Amino Acids =
• Body CAN make them from carbohydrate, fat and a nitrogen source

Amino Acids are “strung” together to make proteins:
• Different Proteins consist of:
– 1)
– 2)
R A B D E

The amino acids and their sequence determines:
- the folding and 3-dimensional shape of the protein
- The 3-dimensional shape dictates the function of the protein

Protein Denaturation:
• A protein subject to heat, acid, alcohol looses its original 3-d shape (it unfolds)

Functions of Proteins:
• 1) Building material
• 2) All Enzymes
• 3) Some Hormones

Functions of Proteins:
• 4) Antibodies
• 5) Fluid Balance
• 6) Acid-Base Balance

Functions of Proteins:
• 7) Transport Proteins
• 8) Structural Components
• 9) Neurotransmitters
• 10) Energy

Body’s 1st Priority = supply Energy to all cells:
If In sufficient CHO or fat
Then sacrifice your own body protein to make energy

Protein Needs Increased:
• 1) Pregnancy
• 2) Growth, (Children, Infants)
• 3) Lactation
• 4) Injury, illness
• 5) Exercise

When making proteins in body :
EAA
NEAA
NEAA
EAA
EAA
EAA
EAA
NEAA
EAA
NEAA
EAA
EAA
NEAA
NEAA
EAA
NEAA
NEAA
X
EAA NEAA EAA NEAA EAA EAA NEAA -NEAA

Complete Protein vs. Incomplete Protein
• 1)
• 2)
• 1)
• 2)
• 3)
• 4)
• 3)

Complementary Proteins:
• Can make plant protein complete by:
• 1)
• 2)
• Combine at least 2 of the following 3 groups:
– 1)
– 2)
– 3)

GRAINS wheat, rye, oatmeal millet, barley rice
SEEDS
Sesame peanuts, walnuts cashews sunflower
DAIRY milk, yogurt cottage cheese cheese ice cream
LEGUMES lentils black beans peas, garbanzo soybeans
= complimentarity only between a few items per group
= complimentarity between several items per group

Rating Protein Quality:
• 1) Does it provide all EAA’s, in correct proportion?
– Animal proteins =
– Plant proteins =
• 2) How well is it Digested and Absorbed?
– Animal protein
– Bean protein
– Grain protein

• Egg white
Protein Rating:
100
• human breast milk 100
• Beef
• Milk protein
• Tuna
• Soybean
• Chickpeas
• Kidney beans
• Rolled oats
• Lentils
• Whole wheat
94
69
68
57
100
100
100
52
40

How to calculate your protein needs:
• Based on desirable body weight
• Based on consumption of mostly animal protein
• Adults:
• If consuming large % of plant protein need more

Food Label Protein Information:
• The % Daily Value depends on whether the food item is animal or plant protein
• Average adult:
– If Animal Protein:
– If Plant Protein:

% Daily Value Calculation: depends on whether food is animal or plant protein
• If animal protein = • If plant protein =

Chili w/ meat vs. Chili w/ Beans
• Protein 12 g • Protein 15 g
• % Daily Value = • % Daily Value =

Upper limit of Protein Intake:
• RDA upper limit =

Excess Protein Intake:
• Xs protein ---> increases B
6 needs
• Pregnant women and infants on xs protein supplements ---> increased Zn excretion in urine
• Infants xs protein ---> deficits in cognitive development
• Xs protein ---> increased Ca ++ excretion in urine

Excess Protein Intake:
• Average American adult consumes about 90 g protein daily
• 70% of this protein comes from animal flesh and dairy products