Protein Flashcards
How many amino acids are there?
20
How many essential amino acids are there?
8
How many amino acids are oxidised as a fuel?
7
Name the 8 essential amino acids?
Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine
Name the 7 amino acids that are oxidised as a fuel?
Alanine Asparagine Glutamate Isoleucine Leucine Lysine Valine
How is net protein balance defined?
MPS - MPB
What is the sedentary protein requirement?
~0.8g/kg/day
How is protein balance measured?
Nitrogen balance techniques
Trancer techniques
The effects of exercise on protein turnover? (Phillips)
Exercise causes stimulation in protein synthesis
Greater increases in muscle protein synthesis following protein ingestion
Less substantial decreases in protein ingestion
What is normal protein turnover? (Phillips)
Both protein synthesis and breakdown follow a sinusoidal pattern
Protein synthesis increases in relation to protein ingestion and decreases over time
Protein breakdown decreases in relation to protein ingestion and increases over time
How to design a study to measure muscle protein synthesis?
Resistance exercise (often unilateral and lower body)
Manipulation of post-exercise protein nutrition
Infusion of labelled amino acids in combination with blood and muscle sampling to determine protein synthesis
The effect of the timing of protein intake on muscle protein synthesis?
Pre-exercise - positive/no effect in MPS
During exercise - enhance MPS during resistance exercise and early recovery
Post-exercise - impact on recovery?
What to take into account to maximise protein synthesis with protein intake?
Body size
Active muscle mass
The protein recommendations to maximise net protein breakdown?
Exercise Consume sufficient energy Consume sufficient high-quality protein Consume at least 20-25g every 3-4hrs Protein intake before bed (30-40g) Protein intake for breakfast
What determines BCAA oxidation rate?
BCAA oxidation rate depends on CHO availability
The importance of protein balance on endurance exercise?
Required for mitochondrial biogenesis
Increased requirements for endurance athletes
The effect of carbohydrate and protein on muscle glycogen resynthesis? (Reviewed by Betts & Williams 2010)
Increases in CHO increases muscle glycogen resynthesis up to 1.2g/kg/h
When protein is added to CHO to can increase muscle glycogen resynthesis when the rate of CHO intake is sub-optimal
What is the protein requirement for endurance athletes?
1.2-1.6g/kg
What is the protein requirement for strength athletes?
1.2-1.7g/kg
What is the recommended daily protein intake?
90-133g (1.3-1.6g/kg) based on 3000kcal/day
What is the suggested protein intake during energy restriction?
Increased protein intake (2g/kg)
Reduces lean tissue loss
What is the relationship between athlete protein intake and energy intake? (Van Erp-Baart et al. 1989)
A positive linear relationship between energy intake and protein consumption
An 80kg novice male bodybuilder wants to gain 15kg of muscle within 1yr. You have advised him that a more reasonable goal would be 5kg. Calculate how much additional protein would be needed per day in order to achieve these targets assuming the correct level of protein intake (1.4g/kg/day or 112d/day) is achieving nitrogen balance?
15kg = 15kg x 0.2 = 3kg protein = 3kg/year = 3000g/year = 8.2g/day = 8.2g + 112g = 120.2g = 120.2g / 80kg = 1.5g/kg/day 5kg = 5 x 0.2 = 1kg = 1kg/year = 1000g/year = 2.7g/day = 2.7g + 112g = 114.7g = 114.7g / 80kg = 1.43g/kg/day
How much protein is in 1kg of lean muscle?
0.2g
A 60kg female endurance athlete is advised that she should be achieving a daily protein intake of 1.2g/kg/day. Analysis of her food intake records indicates that her total daily energy intake is 12kJ and that her protein intake provides 12% of this energy. Calculate her actual intake of protein in g/kg/day. Does she need to supplement her diet with extra protein? You can assume that the energy available from dietary protein is 17kJ/d
Actual
= 12000 x 0.12 = 1440kJ of protein
= 1440kJ / 17kJ/g = 84.7g protein
= 84.7g / 60kg = 1.41g/kg/day of protein
= No she does not need to supplement with extra protein because she’s consuming above 1.2g/kg/day of protein
In the study by Josse et al. (2010), 2 groups of underwent 12wks of progressive resistance exercise. One group received 1L semi-skimmed milk and the other 1L of CHO solution. The semi-skimmed milk group gain 1.9kg of lean mass and lost 1.6kg of fat mass. From these values estimate the average energy balance that subjects experienced. Also, estimate this as daily energy balance? You can assume the energy values of 38kJ/g of fat and 17kJ/g protein
Fat = 1600g x 38kJ = 60800kJ Protein = 1.9kg x 0.2 = 380g = 380g x 17kJ = 6460kJ Energy Balance = 60800kJ - 6460kJ = 54340kJ = 54340kJ / 84days = 647kJ/day
= energy balance is -647kJ/day
Which of these is an essesntial amino acids is branched?
- lysine
- valine
- threonine
- histidine
Valine
What is the effect of resistance exercise on MPS and MPB?
Increases MPS and MPB
Leucine appears to potentiate MPS through stimulation of?
Mammalian target of rapamycin (mTOR)
