Week 8 - Optimizing anabolic responses with protein nutrition

Question 1

What amino acid is thought to be particularly important in initiating muscle protein synthesis?

Answer 1

Leucine

Question 2

Important amino acids in initiating muscle protein synthesis

Answer 2

Leucine, Glutamine, Valine, Isoleucine, Lysine

Question 3

Only ____ are required to increased muscle protein synthesis after exercise.

Answer 3

Essential amino acids

Question 4

What protein source leads to greater lean body mass increases - Soy or Milk protein?

Answer 4

Milk protein

Question 5

What is in milk that makes it more effective than soy protein?

Answer 5

Milk protein is 20% whey protein and 80% casein protein - whey protein and casein have higher amounts of essential amino acids such as leucine compared to soy protein.

Question 6

How does whey protein and casein protein differ?

Answer 6

1. Contain two different proportions of essential amino acids: whey protein has a greater amount of total essential amino acids (leucine) compared to casein.
2. Different digestion and absorption kinetics: whey protein is fast-acting (its absorbed quickly) whereas casein is slow-acting.

Question 7

Is leucine greater in soy protein, whey protein or casein?

Answer 7

Whey protein (12.2) compared to casein (8.9) and soy (8.2)

Question 8

Muscle protein synthesis rates are greatest in rested and exercises muscle with what type of protein ingestion? Explain this.

Answer 8

Whey protein ingestion - greater total essential amino acids (49.2) such as leucine + rapid digestion and absorption properties (rapid appearance in circulation)

Question 9

What are potential techniques to make plant-based proteins more effective, in terms of their anabolic properties?

Answer 9

1. Consuming more to meet essential amino acids requirements.
2. Blend plant-based proteins together to make up for specific amino acid deficiencies (Soy-corn blend).

Question 10

What is a potential role for slow-acting proteins such as casein?

Answer 10

Ingestion of casein before sleep can increase overnight muscle protein synthesis and create a positive protein net balance rather than a negative balance.

Question 11

What frequency of protein ingestion maximizes muscle anabolic response over 12hrs post-exercise…
a) 40g every 6 hours
b) 20g every 3 hours
c) 10g every 90mins

Answer 11

B - this keeps muscle protein synthesis levels relatively high

Question 12

What is the influence of resistance exercise on the anabolic response post-exercise?

Answer 12

Resistance exercise prolongs muscle anabolic sensitivity to protein provision for 1-2days.

Question 13

Total EAAs in whey protein, casein protein and soy protein.

Answer 13

Whey is 49.2
Casein 40.7
Soy is 36.

Question 14

Leucine in whey protein, casein protein and soy protein.

Answer 14

Whey protein 12.2
Casein protein is 8.9
Soy protein is 8.2

Question 15

What are the two properties of dietary protein that are thought to impact its capacity to increase post-exercise MPS?

Answer 15

EAA content and digestibility

Question 16

Evidence suggests that slowly digested proteins, such as casein, can be used to support muscle anabolism and growth in the overnight period. Outline the evidence from acute and chronic studies to support this notion.

Answer 16

Acute pre-sleep casein protein intake augments overnight MPS rates and net protein balance is positive.
Chronic pre-sleep casein protein intake during resistance exercise training augments muscle growth, specifically the change in type II fibre CASA is greater.