Protein Intake And Metabolism Flashcards
AMDR for 1-3 years of age
45-65% CHO
5-20% protein
30-40% fat
ADMR for 4-18 yrs
45-65% CHO
10-30% protein
25-35% fat
ADMR for 19 years and older
45-65% Cho
10-35% protein
20-35% fat
Practical issues/concerns with using 10-35% of total calories for protein
- how would you know what to eat
- how much protein to have at one time
- would need to calculate energy needs (kcal/day)
What do most sport dieticians do to calculate AMDR for protein
Use values based on an athletes body weight
Example: energy needs 2,500 kcal/day, 21 yrs, protein range 250kcal to 875kcal
10%= 250kcal/4kcal per gram = 62.5g/day
35%= 875kcal/4kcal per gram = 218g/day
9 Protein functions
- Structural
- Transport
- Enzyme
- Hormone/neurotransmitter
- Immune
- Acid-base balance
- Fluid balance
- Energy (4kcal/g)
- Movement (skeletal muscle)
Structural
Vital constituents of all cells
Transport proteins
Of various substances in the blood
Protein for enzymes
Form almost all enzymes in the body
protein for hormone/neurotransmitters
Formation of insulin, etc
Protein for immune
Formation of antibodies, etc
Protein for acid-base balance
Buffering within the blood to maintain optimal pH
Protein for fluid balance
Exerting osmotic pressure to maintain optimal fluid balance within the body
What does protein contain
C,H,O and nitrogen
What does protein digestion enable
Amino acids to enter the “amino acid pool”
- blood, liver, peripheral tissues (i.e. muscle)
- broken down to AAs
Amino acids in one area are in constant
Equilibrium with another (tightly regulated)
Upon food digestion, how are proteins degraded
To amino acids by proteases (enzyme) in stomach and small intestine
What is protein broken down to in stomach
Polypeptides
What are polypeptides broken down into
Tripeptides, dipeptides, amino acids
Where does final breakdown to amino acids happen
In small intestine
Where are the amino acids absorbed
In portal vein and transported to liver
(Liver is critical centre in AA metabolism)
What is constantly clearing and moving AAs around body
Liver
How fast amino acids cleared once enter blood
5-10 mins
- certain digested quicker than others
Rate of digestion of protein is dependent on
Protein type and composition of the meal/snack
Fast absorption protein
Induce a large increase in whole body protein synthesis and oxidation with minimal affect on whole body protein breakdown
Example of fast absorption proteins
Whey or soy protein
Slow absorption protein
Induces a change in whole body protein turnover, small increase in synthesis and oxidation and a large reduction in protein breakdown
Example of slow absorption protein
Casein (e.g., chunks in cottage cheese)
How many amino acids
20