Transcript Proteins, Amino Acids

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 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:
NEAA
EAANEAA
EAA
EAA
NEAA
EAA
EAA
EAA NEAA
EAA
EAA
NEAA
NEAA EAA
NEAA
NEAA
X
EAA-NEAA-EAA-NEAA-EAA-EAA-NEAA -NEAA
Complete Protein
• 1)
vs.
Incomplete Protein
• 1)
• 2)
• 2)
• 3)
• 3)
• 4)
Complementary Proteins:
• Can make plant protein complete by:
• 1)
• 2)
• Combine at least 2 of the following 3 groups:
– 1)
– 2)
– 3)
GRAINS
SEEDS
wheat,
rye, oatmeal
millet, barley
rice
Sesame
peanuts, walnuts
cashews
sunflower
DAIRY
LEGUMES
milk, yogurt
cottage cheese
cheese
ice cream
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
•
•
•
•
•
•
•
•
•
•
•
Protein Rating:
Egg white
human breast milk
Beef
Milk protein
Tuna
Soybean
Chickpeas
Kidney beans
Rolled oats
Lentils
Whole wheat
100
100
100
100
100
94
69
68
57
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 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