Muscle Recovery >> Whey, Casein or Soy?
There number of types of protein powders on the market is forever expanding. They range from milk-based to those of plant origin to even powdered beef and chicken protein. Of all those available, however, it’s whey and casein that are the two most popular powders of animal origin, whereas soy powder takes top spot for vegan protein. Knowing which to use to best recover after hard training or a match should be a straightforward decision. This brief article will hopefully convince you so.
In a 2009 study,1 Tang and colleagues recruited three groups of six young men. The three groups performed four sets of leg press and knee-extensions at a workload equivalent to 10-12 reps. Exercise was immediately followed by consumption of a whey (21.4g), casein (21.9g) or soy (22.2g) drink. The varied quantity of the three drinks was to ensure the amount of protein in each provided 10g of essential amino acids.
• Muscle protein synthesis (MPS) is the process of using amino acids to repair and create (synthesise) new proteins for muscle growth.
• MPS following the whey protein drink was 122% greater than casein, and 31% greater than soy.
• Study conclusion: whey hydrolysate stimulated MPS to a greater degree than soy and casein after resistance exercise.
Why is Whey more beneficial?
• Although all three protein drinks stimulated a rise in blood concentrations of the nine essential amino acids (EAA), at 30 and 60 minutes after ingestion, the rise in EAAs, was greater following whey protein compared to soy and casein.
• Branched-chain amino acids, which represent 3 of the 9 EAAs and include leucine, are important in ‘activating’ the genes and signalling proteins involved in repairing and building new muscle tissue.
• Whey protein has a higher content of branch-chain amino acids and leucine compared to soy or casein, explaining the greater increase in protein synthesis after whey supplementation.
• Additionally, whey protein is more rapidly digested than soy and casein. This results in the amino acids appearing in the bloodstream quicker and activating MPS faster than soy or casein.
• Conclusion: the higher content of branch-chain amino acids, specifically leucine, in whey protein, alongside the rapid absorption of these amino acids into the bloodstream, are responsible for whey proteins greater effect on muscle recovery compared to soy or casein. As such, a whey protein isolate or hydrolysate supplement is recommended.
1. Tang, J. E., Moore, D. R., Kujbida, G. W., Tarnopolsky, M. A. & Phillips, S. M. Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. J Appl Physiol 107, 987–992 (2009).