The combination of resistance exercise and protein ingestion has a positive effect on muscle protein balance acutely after a workout. If the training is maintained over time the muscle mass may increase. Whether supplementing the diet with extra protein has an additional effect on the accretion of muscle mass is debated. Further, the importance of the quality of the protein in these supplements is unclear. An increased knowledge on how to optimize muscle growth is of interest to young and elderly, both from a health and sports perspective.
Place: Norwegian School of Sport Sciences
Effects of strength training and supplementation with different milk proteins on regulation of muscle mass in young and elderly
The aim of this project was to compare the acute and long-term muscle anabolic effects of supplementing with three different milk protein products (native whey, regular whey concentrate and milk) in combination with resistance exercise in young and elderly (+70 yrs) participants.
The project consists of three acute studies and two long-term training studies. In total 77 young and 60 elderly participants were included in the studies. The first acute study investigated the effects of several different milk protein products affected the blood concentrations of amino acids after a bout of resistance exercise in young men.
In the next two acute studies we investigated the effects of native whey, regular whey protein concentrate and milk on acute anabolic signalling and muscle protein synthesis in young and elderly men and women.
In the training studies we investigated the effect of native whey or milk supplementation during a strength-training period (12 weeks in young and 11 weeks in elderly) on muscle growth and gains in strength in young and elderly participants. In addition we investigated how the acute effects of a bout of resistance exercise changed from the first bout, when participants were untrained, to the last bout when they were more trained.
In the first acute study, we found native whey to increase blood concentrations of leucine to a greater extent than several forms of whey proteins and milk. Despite greater leucine concentrations in blood with native whey, we observed no differences in phosphorylation of p70S6K, 4E-BP1 and eEF-2, or muscle protein synthesis between native whey and WPC-80 in young or elderly individuals in the following acute studies. However, native whey induced a greater post resistance exercise phosphorylation of p70S6K and higher rates of muscle protein synthesis than milk in young and elderly. In the training studies, native whey was compared to milk. The acute difference for p70S6K phosphorylation between native whey and milk observed in the acute study was not reproduced in these studies. Most participants experienced gains in muscle mass, and all improved their muscle function. Still, no differences were observed between the supplements for any outcome in the training studies.
In summary, no clear benefit on acute anabolic outcomes were evident with post resistance exercise ingestion of native whey compared to WPC-80. The potentially greater acute anabolic effect of post resistance exercise ingestion of native whey compared to milk is unclear, as our results were equivocal. However, for the long-term outcome measures, no differences were observed between native whey and milk.