Effects of a leucine-enriched amino acid supplement on muscle mass, muscle strength, and physical function in post-stroke patients with sarcopenia: A randomized controlled trial

Abstract

The aim of this study was to investigate the effects of a leucine-enriched amino acid supplement on muscle mass, muscle strength, and physical function in post-stroke patients with sarcopenia. We conducted an eight-wk, two-parallel group intervention, randomized controlled, blinded outcome assessment among 44 post-stroke older patients with sarcopenia. Sarcopenia was defined as a loss of skeletal muscle mass and decreased muscle strength according to the Asian Working Group for Sarcopenia criteria. The intervention group (n = 21) received a leucine-enriched amino acid supplement; the control group (n = 23) did not. Both groups performed low-intensity resistance training in addition to a post-stroke rehabilitation program. A primary outcome of physical function by using the motor domain of Functional Independence Measure (FIM), and secondary outcomes of appendicular muscle mass (skeletal muscle mass index [SMI]) measured via bioelectrical impedance analysis and muscle strength as handgrip strength were measured at baseline and at the end of the intervention. The FIM score increased significantly in both groups over time (P < 0.01), with significantly greater improvement in the intervention group than in the control group (P < 0.045). Handgrip strength also increased significantly over time (P <0.05), with significantly greater improvement in the intervention group (P < 0.01). The SMI increased significantly in the intervention group but not in the control group over time, with significantly greater improvement in the intervention group (median estimated difference, 0.50 kg/m2; 95% confidence interval, 0.01-2.11). We demonstrated that an eight-wk intervention consisting of a leucine-enriched amino acid supplementation and low-intensity resistance training increased muscle mass, strength, and physical function in post-stroke patients with sarcopenia.