Researchers from Denmark are among the first to uncover some of the specific mechanisms governing accelerated muscle growth in response to resistance exercise and whey protein supplementation. A study just published in the journal Amino Acids has found that a high quality whey protein hydrolysate supplement combined with carbohydrate lead to a greater stimulation of skeletal muscle satellite cells following weight training than in individuals doing the same type of weight training but only receiving carbohydrate.
The study subjected individuals to the hardest type of weight training, namely eccentric. They also used a very invasive protocol, which required subjects to undergo muscle biopsies on five different occasions over 7 days. Another important point about the study was that the subjects supplemental protein intake was over and above their normal dietary protein intake. To be precise the total additional supplementary protein ingestion was 84 g/day and the BCAA ingestion was 23.0 g/day for the whey group.
Subjects undertook one solid session of eccentric weight training, after which they had three shots of either the hydrolysed whey protein combined with carbohydrate or carbohydrate alone. Test subjects were also required to take the supplements 3 times a day for the following two days. As far as the actual composition of the whey and carb supplement was concerned, it was an 8% solution that consisted of 28g of whey protein hydrolysate and 28g of carbohydrate. In the group only receiving carbohydrate, their drink simply consisted of 56g of carbs (i.e. isocaloric). As mentioned at the outset, the hydrolysed whey was very high quality. It provided 27.7% BCAA (leucine 14.2%, isoleucine 6.6% valine 6.9%) and 53.3% essential amino acids. What’s more, the protein contained a minimum of 75.7% peptides that all had a length of three amino acids or less. So in essence, the hydrolysed whey protein had extremely high levels of di- and tri-peptides.
Compared with the group only receiving the carbohydrate, the whey hydrolysate + carb group had significantly higher muscle satellite cell proliferation, which occurred within a narrower time frame (i.e. 48hr vs 7 days). In addition, the increased cell numbers were predominantly confined to type II muscle fibers. This study is crucial in that it has uncovered a mechanism by which whey protein hydrolysate supplementation augments muscle growth following weight training. It will be interesting to see if these findings can be replicated in future studies with other whey proteins or whether these effects might be confined to hydrolysed whey proteins with a very high degree of hydrolysis and di- and tri-peptide content.
Farup J, et al. Whey protein supplementation accelerates satellite cell proliferation during recovery from eccentric exercise. Amino Acids. 2014 Jul 26. [Epub ahead of print]