In this double-blind, randomized, clinical trial, 19 young adults were studied before and after ingestion of approximately 19 g of protein blend (PB) or approximately 18 g whey protein (WP) consumed 1 h after high-intensity leg resistance exercise. The blend consisted of 25% soy, 25% whey and 50% casein. Whey protein ingestion resulted in higher and earlier amplitude of blood branched chain amino acid concentrations. The blend led to a lower initial rise in blood branched chain amino acids but sustained elevated levels later into recovery (P < 0.05). Post-exercise protein fractional synthetic rate increased equivalently in both groups during the early period; however, it remained elevated only in response to the blend. Therefore, the results suggest the blend is superior to whey along for building muscle in response to resistance exercise.
Reidy et al. J Nutr.