2) A small dose of 6.25 grams of whey protein with added leucine
3) The small whey dose of 6.25 grams with added EAAs that included leucine
4) The small whey dose of 6.25 grams with added EAAs but no leucine
When leucine was added to the small 6.25 gram whey dose, it made the total leucine content of these drinks equivalent to that of the 25-gram dose.
Results showed that all four post-workout drinks elevated muscle protein synthesis in near equal amounts, but only the 25-gram dose of whey maintained muscle protein synthesis at five hours after the workout. The two supplements with added leucine were more effective at enhancing protein synthesis than the 6.25 gram-dose of whey without leucine, indicating that leucine plays an important role in recovery.
Previous studies have shown that leucine activates a muscle signaling pathway that triggers tissue regeneration. In older individuals over age 50, research shows that this pathway (called the mTOR pathway) is only turned on if leucine is present in the body. This study shows that in these younger trainees, the pathway is better sustained for a longer period of leucine is present, although not as long as if a large dose of whey is ingested—something about the whey protein makes it most effective.
Researchers do not know the reason that only the large whey dose produced sustained recovery, but it may be due to the larger amount of non-essential amino acids (NEAAs) present in the 25-gram dose. There are 13 grams of NEAAs in 25 grams of whey, whereas there were only 3.3 grams in all the other doses.
Take away from this study that for best recovery and muscle building you should take a 25-gram dose of whey post-workout. Take branched-chain amino acids during your workout because they have been shown to prevent soreness from training by minimizing tissue damage. If you can’t take the large whey dose, a smaller dose with added EAAs that include leucine will still support recovery, just not as much. Although not tested in this study, consider dosing with more whey or EAAs a few hours after training.
Churchward-Venne, T., Burd, N., et al. Supplementation of Suboptimal Protein Dose with Leucine or EAAs: Effects of Myofibrillar Protein Synthesis at Rest and Following Resistance Exercise in Men. Journal of Physiology, 2012. Published Ahead of Print.