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 sequencedetermines:

- 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 Insufficient 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:

NEAAEAA

EAAEAA

NEAAEAA

EAA-NEAA-EAA-NEAA-EAA-EAA-NEAA-NEAA

NEAA

NEAA EAA

EAANEAA

NEAA

NEAA

EAA

EAANEAA

EAA

X

Complete Protein vs. Incomplete Protein

• 1)

• 2)

• 3)

• 4)

• 1)

• 2)

• 3)

Complementary Proteins:• Can make plant protein complete by: • 1)

• 2)

• Combine at least 2 of the following 3 groups:

– 1)

– 2)

– 3)

GRAINSwheat,

rye, oatmealmillet, barley

rice

SEEDSSesame

peanuts, walnutscashews

sunflower

LEGUMESlentils

black beanspeas, garbanzo

soybeans

DAIRYmilk, yogurt

cottage cheesecheese

ice cream

= 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

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

• % Daily Value =

• Protein 15 g

• % Daily Value =

Upper limit of Protein Intake:

• RDA upper limit =

Excess Protein Intake:

• Xs protein ---> increases B6 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