Effects of leucine-enriched whey protein supplementation on physical function in post-hospitalized older adults participating in 12-weeks of resistance training program: a randomized controlled trial

Age-related strength and muscle mass loss is further increased after acute periods of inactivity. To avoid this, resistance training has been proposed as an effective countermeasure, but the additional effect of a protein supplement is not so clear. The aim of this study was to examine the effect of a whey protein supplement enriched with leucine after resistance training on muscle mass and strength gains in a post-hospitalized elderly population. A total of 28 participants were included and allocated to either protein supplementation or placebo supplementation following resistance training for 12 weeks (2 days/week). Physical function (lower and upper body strength, aerobic capacity and the Short Physical Performance Battery (SPPB) test), mini nutritional assessment (MNA) and body composition (Dual X-ray Absorptiometry) were assessed at baseline and after 12 weeks of resistance training. Both groups showed improvements in physical function after the intervention (p < 0.01), but there were no further effects for the protein group (p > 0.05). Muscle mass did not improve after resistance training in either group (p > 0.05). In conclusion, 12 weeks of resistance training are enough to improve physical function in a post-hospitalized elderly population with no further benefits for the protein-supplemented group.

This study was supported by the Basque Government (2016111138), and the European Regional Development Funds (ERDF), the University of Granada Plan Propio de Investigación 2016 (Excellence Actions: Unit of Excellence on Exercise and Health [UCEES]) and the Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades (ERDF: ref. SOMM17/6107/UGR). MA was supported by a grant from the University of the Basque Country (PIF17/186), IE by a grant from the University of the Basque Country in collaboration with the University of Bordeaux (Université of Bordeaux (UBX)) (PIFBUR16/07) and JRR by grants from the Spanish Ministry of Economy and Competitiveness (RYC 2010-05957; RYC-2011-09011 and BES-2014-068829).This work was also supported by grants from the Public University of Navarra, 'Plan de Promoción de Grupos de Investigación (2019)'.