For a while now we have seen a seen a push for more leucine in our supplements. First we seen an increase in the traditional 4:1:1 BCCA blends and now we see leucine being added to protein powders. Now the question is, is this scientifically founded? I mean we know leucine plays a role in improving muscle protein synthesis (MPS). It stimulates anabolic signalling by activating mammalian target of rapamycin (mTOR) which leads to increased muscle protein synthesis and hypertrophy.
This is great for leucine but this doesn't answer the question, is their any benefit to adding leucine to our protein? Considering whey and casein both already contain leucine is it possible more is better?
Well, lucky for us there was recently this study published in the American Journal of Clinical Nutrition
View attachment Leucine Whey dosage AJCN 2014.pdf
What the researchers set out to do was to see if adding leucine to a low protein shake would improve MPS. They recruited forty 21 year old men and measured protein synthesis before and after the drink.
The drinks that were given were either;
*25 g whey protein (3g leucine)
*6.25 g whey protein (0.75g leucine)
*6.25 g whey protein + low leucine (total of 3g leucine)
*6.25 g whey protein + high leucine (total of 5g leucine)
*6.25 g whey protein + BCAA (total of 5g leucine)
The subjects performed unilateral knee-extensors (leg extensions) prior to taking the drink and MPS was measured both under resting and exercising conditions.
What were the results? It should come to no surprise that the ones who consumed the whey + high leucine experienced asignificant increase muscle synthesis along with the ones who consumed 25g whey when compared to the other beverages.
So adding leucine to just 6.25g of whey can increase MPS to the same extent that 25g of whey can.
A few questions that come to mind when reading this paper is;
*Why didnt the 6.25g + low leucine increase MPS similar to the 25g whey considering both had a total of 3g leucine?
*Why did the 25g whey increase MPS higher (was only slightly higher) than the 6.25g + high leucine considering it is 3g leucine vs. 5g leucine?
While I do find the results of this study interesting, I would like to see future studies done with a greater amount of protein +leucine like say 45g whey + leucine vs. just 45g whey. In the meantime it would appear that adding leucine to a protein shake may have some merit after all
*NOTE* The full text to the paper is attached for your reading pleasure
This is great for leucine but this doesn't answer the question, is their any benefit to adding leucine to our protein? Considering whey and casein both already contain leucine is it possible more is better?
Well, lucky for us there was recently this study published in the American Journal of Clinical Nutrition
View attachment Leucine Whey dosage AJCN 2014.pdf
What the researchers set out to do was to see if adding leucine to a low protein shake would improve MPS. They recruited forty 21 year old men and measured protein synthesis before and after the drink.
The drinks that were given were either;
*25 g whey protein (3g leucine)
*6.25 g whey protein (0.75g leucine)
*6.25 g whey protein + low leucine (total of 3g leucine)
*6.25 g whey protein + high leucine (total of 5g leucine)
*6.25 g whey protein + BCAA (total of 5g leucine)
The subjects performed unilateral knee-extensors (leg extensions) prior to taking the drink and MPS was measured both under resting and exercising conditions.
What were the results? It should come to no surprise that the ones who consumed the whey + high leucine experienced asignificant increase muscle synthesis along with the ones who consumed 25g whey when compared to the other beverages.
So adding leucine to just 6.25g of whey can increase MPS to the same extent that 25g of whey can.
A few questions that come to mind when reading this paper is;
*Why didnt the 6.25g + low leucine increase MPS similar to the 25g whey considering both had a total of 3g leucine?
*Why did the 25g whey increase MPS higher (was only slightly higher) than the 6.25g + high leucine considering it is 3g leucine vs. 5g leucine?
While I do find the results of this study interesting, I would like to see future studies done with a greater amount of protein +leucine like say 45g whey + leucine vs. just 45g whey. In the meantime it would appear that adding leucine to a protein shake may have some merit after all
*NOTE* The full text to the paper is attached for your reading pleasure