L8.2 Nutritional Interventions Flashcards
How does CHO intake affect protein synthesis?
- CHO intake does not affect protein synthesis
- Basal insulin levels already near max protein syn levels
Effect of essential AA intake on protein synthesis?
- ↑essential AA intake → ↑post-ex protein synthesis
- Also ↑phosphorylation of 4E-BP1 (causing it to dissociate from e1F4E, activating it → ↑protein synthesis)
How much protein is needed for max protein synthesis?
25g protein intake → enough to stimulate max protein synthesis
What is the effect of continuous AA feeding?
- Effect of AA availability of protein synthesis is relatively short → back to basal levels after ~6hrs
Content of milk?
~3% protein → 80% Casein, 20% Whey (↑digestion, circulation)
How does digestion relate to protein synthesis stimulation?
- ↑Digestion → ↑circulation → ↑response: ∴ Whey>casein response
- Whey also has ↑[Leucine]
Effect of leucine on protein synthesis?
- Stimulates MPS & inhibits muscle proteolysis
- Leucine-tRNA synthetase → GTP → mTOR
- ∴ Leucine content in meals affect anabolic response
What are the different recommended protein intakes?
RDI
Strenuous exercise
Normal diet
RDI: 0.75-0.80g/kg (minimal intake, not optimal)
Strenuous exercise: 1.2-1.7g/kg
Normal diet: ~1.4g/kg
How does a high protein diet assist in weight loss?
↑Protein intake during weight loss ↓loss of muscle mass → more favourable body composition
Which meal is usually most deficient in protein?
Breakfast usually has lowest protein content & represents biggest opportunity to ↑protein intake
Difference in nutritional supplements in elderly
- Post-ex protein intake → DOES NOT ↑muscle mass
- Soy vs whey → no diff
- 12 weeks leucine supplements → x ↑ muscle mass & str
Potential of glycine?
- Glycine: Potential anti-inflammatory agent (↓tumour growth & muscle wasting)
- ↓Atrogin mRNA expression
- ↓ROS
- ↓methylation of DNA
