Protein 2

Question 1

What are the chronic effects of protein?

Answer 1

• 12 weeks resistance exercise training (5 sessions a week) with milk, soy or carbohydrate intake post-exercise
• Milk enhanced body composition changes with resistance exercise, 3 separate groups
• Milk group had skimmed 500ml of skimmed milk twice post-exercise - amplified protein synthesis compared to the soy
• Soy had energy and nutrient matching
• CHO had same energy matching of the other 2 groups

Question 2

How was the milk protein group affected in the females data?

Answer 2

Female data - protein source increased lean mass(milk)
- Milk group had favourable effect on fat mass(substantial decrease), shown to a lesser extent in the male group. Called body re-composition, usually happens in the early stages of exercise training

Question 3

How was Whey related to the proportion of fat free mass?

Answer 3

• Whey protein supplementation increase resistance-training induced gains in fat-free mass compared to soy and carbohydrate.
• Whey was better(high quality) than soy and CHO
• Soy gives less of a response of protein synthesis, higher consumption could level out the benefit
• Protein supplementation after 3 months does not provide much benefit

Question 4

What impact did the use of protein supplementation have?

Answer 4

• Protein supplementation produced small, but significant increases in:
  
  • 1RM Strength - more beneficial to have greater strength for the same muscle size
  • Fat-free mass
  • Muscle size - very small effect from protein supplementation
• No effect on fat-free gain mass when protein intake >1.62 g/kg/day
• Protein intake is usually measured through dietary analysis, disadvantage as it is self-reported(usually means underreporting of calories), or change behaviour to eat less food during the report time

Question 5

Why is energy intake important for hypertrophy/strength?

Answer 5

No change in lean mass results in an energy deficit of about 500kcal per day
15% of their daily intake
- Maintaining energy balance will drive the production of lean mass, being in a surplus is important to gain lean mass

Question 6

How can exercise increase leucine oxidation?

Answer 6

• BCAA’s oxidised during exercise, rest to exercise increases leucine’s burnt(raises requirement for amin acid intake)
  
  • Oxidation rate is dependent on CHO availability
• Generally contribute <5% energy
  
  • Not a major contributor
  • Can be up to 15% in some situations
• Required for mitochondrial biogenesis - for endurance athletes
• Increased requirements for endurance athletes

Question 7

What is the difference between muscle turnover in resistance vs endurance training?

Answer 7

Mitochondrial fraction - responds to both types of exercise
- Resistance trained people after 10 weeks showed amplified muscle turnover(at rest)
- No change in endurance trained group
- After 10 weeks only amplification in mitochondrial fraction in response to resistance training

Question 8

What are the implications of alcohol on MPS?

Answer 8

• Alcohol ingestion in large amounts reduces muscle protein synthesis
• Causes stepwise increases across the 3 conditions
• Maximising MPS response should be avoiding alcohol in large quantities
• Sufficient protein intake with alcohol intake will reduce the impact of alcohol

Question 9

What are the effects of protein intake during exercise?

Answer 9

• During ride:
  
  • 65 g/ h carbohydrate
  • 65 g/ h carbohydrate +19 g/ h protein
• Performance similar between trials was not different, no benefit of having protein(no drawback of having protein)
• Could cause more GI discomfort

Question 10

What is the CHO intake for optimal glycogen synthesis?

Why is this not always achievable?

Answer 10

1-1.2 g/kg/h is optimal for glycogen synthesis
- Less than optimal CHO ingestion, with protein intake is beneficial for muscle glycogen resynthesis
- Difficult to do, not possible to only ingest CHO(mainly have a mixed meal 4hrs post-exercise)

Question 11

What is protein’s role in post-exercise rehydration?

Answer 11

• Exercise-induced dehydration followed by rehydration with two drinks:
  
  • Carbohydrate-only
  • Carbohydrate-milk protein
• Addition of milk protein enhances rehydration - increases muscle protein, glycogen resynthesis and rehydration
• protein ingestion has little effect on the ability to augment postexercise rates of mitochondrial protein synthesis

Question 12

What are the endurance training adaptations that can be seen from protein and CHO intake?

Answer 12

• Carbohydrate protein intake enhances adaptation to endurance training - endurance benefit
• Vo2max measured before and after - see an amplified response in the CM condition, protein + CHO condition saw amplified effects
• Relative increase was slightly bigger than absolute increase = means that the body mass changed/ body recomposition
• Question of whether milk is a supplement
• dietary amino acids are preferentially utilized to support greater rates of MPS in the immediate postexercise period with remodelling of whole-body proteins (including the gut) occurring as a secondary process.

Question 13

What are the protein requirements for these athletes?
- sedentary
- endurance
- strength

How might this differ for an athlete with an energy restriction?

Answer 13

• Sedentary: 0.8 g/ kg
  
  • Endurance athletes: 1.2-1.6 g/ kg
  • Strength athletes: 1.2-1.7 g/ kg - similar requirements in older adults to reduce loss in muscle mass
• 3000 kcal/ day (12-15% protein)
  90-113 g/ day (1.3-1.6 g/ kg (for a 70 kg athlete
• Increased requirement during energy restriction: 2 g/ kg (most athletes are between 1.6-2)
  
  • Reduces lean tissue loss

Question 14

How are energy intake and protein correlated?

Answer 14

Looks at correlation between energy and protein intake
- Absolute intake of a nutrient is correlated with energy intake
- Each data point is a group of athletes
- Highest calory intake are body builders, due to protein supplements intake
- Nower days most people will be raised slightly because most athletes are on protein supplements
- the co-ingestion of protein and CHO may enhance glucose uptake in the muscle via stimulation of glucose transporters, which ultimately would translate into a greater rate of muscle glycogen resynthesis

Question 15

What is proteins impact on immune function?

Answer 15

• higher protein intakes are associated with a reduction in the self-reported incidence of upper respiratory tract infections in athletes when undertaking intensified training loads
• May help mitigate the risk of developing upper respiratory infections in athletes.