Efficacy of leucine-rich high protein supplementation on body composition and muscle function among older adults with sarcopenia: a randomized controlled trial.

To evaluate the effect of leucine-rich high protein supplementation on body composition, muscle function and gene expression among older adults with or at risk of sarcopenia residing in Klang Valley, Malaysia. A total of 47 participants were recruited into this 12-week double-blinded, randomized controlled trial. Intervention group consumed 2 sachets of high protein supplement daily contributing to 50.6 g of protein/day and 6 g of leucine/day. Control group received placebo supplement. Body composition was assessed via anthropometry measurements, bioelectrical impedance analysis (BIA), and magnetic resonance imaging (MRI) of left mid-thigh. Meanwhile, muscle function was assessed using short physical performance battery (SPPB). A total of 16 ml of full blood was collected pre- and post- study to assess participants' health profiling and changes in gene expression as determined by mitochondrial RNA activity derived from the peripheral blood mononuclear cells. The measurements were performed at 0, 6, and 12 weeks. Participants were mostly women (89.4%) with a mean age of 69.3 ± 7.1 years. Repeated measures ANOVA showed no significant intervention effect in body composition (anthropometry measurements and BIA) as well as muscle function (SPPB score). However, genes responsible for adenosine triphosphate (ATP) production (GBA, MLYCD), cell proliferation (STAT5A) and DNA repair (BRCC3) were significantly up-regulated in intervention group (p < 0.05). Leucine-rich high protein supplementation did not produce significant changes in body composition or muscle function in older adults with sarcopenia. However, it showed potential in improving gene expression. Further studies with a longer supplementation period and a larger sample size might be needed for noticeable changes, particularly for body composition.