Effect of protein blend vs whey protein ingestion on muscle protein synthesis following resistance exercise

Abstract

Resistance exercise followed by the ingestion of amino acids or protein causes an additive stimulation of muscle protein synthesis (MPS). Proteins such as whey are digested at a fast rate whereas soy and casein are digested at an intermediate and slow rate, respectively. To determine if ingestion of a protein blend (soy and dairy protein) extends the post‐exercise MPS response compared to whey protein we conducted a double‐blind, randomized clinical trial in 20 young adults before and after ingestion of ~20g of the protein blend or whey (N=10 per group) given 1h after a bout of high‐intensity leg resistance exercise. We utilized stable isotopic methods to measure the mixed muscle protein fractional synthetic rate (FSR) and western blotting to examine mTORC1 signaling. Muscle biopsies (vastus lateralis) were collected at baseline and at two time points during post‐exercise (Early: 1–3h & Late: 3–5h post‐ex). We report differences between the two beverages as Protein A and B (data will be unblinded at the EB meeting). FSR increased by ~40–70% in both groups during Early and remained elevated into Late. Protein A and B also activated mTORC1 signaling to a similar extent following exercise, yet Protein B tended to be greater. We conclude, from these preliminary data that following resistance exercise, the ingestion of a protein blend enhances mTORC1 signaling and MPS similarly to that of whey protein.Grant Funding Source : Solae LLC