Effect of whey protein supplementation after resistance exercise on the muscle mass and physical function of healthy older women: A randomized controlled trial

AimTo evaluate the effectiveness of a 24-week program of nutritional supplementation using whey protein, ingested after resistance exercise, in increasing muscle mass and physical function among community-dwelling healthy older Japanese women. MethodsWe carried out a randomized controlled trial, with 81 healthy women, aged 65-80years, allocated to three groups of 27 participants each: the exercise and protein supplementation group, the exercise only group, and the protein supplementation only group. A 24-week program of resistance exercise, carried out twice per week, was combined with whey protein supplementation, containing 22.3g of protein. The total protein intake for participants in all three experimental groups was adjusted to a level of at least 1.2g/kg bodyweight/day, and more during the intervention period. Between-group differences in the pre- to post-intervention change in skeletal muscle mass and physical function were evaluated using an analysis of variance. ResultsThe pre- to post-intervention increase in the skeletal muscle mass index was significantly higher for the exercise only group than for the protein supplementation only group (P=0.008), and significantly higher for the exercise and protein supplementation group than for either the exercise only (P=0.007) or protein supplementation only (P<0.001) groups. Similarly, the increase in grip strength and gait speed was significantly greater for the exercise and protein supplementation group than for the protein supplementation only group (grip strength P=0.014, gait speed P=0.026). ConclusionsWhey protein supplementation, ingested after resistance exercise, could be effective for the prevention of sarcopenia among healthy community-dwelling older Japanese women. Geriatr Gerontol Int 2018; 18: 1398-1404.