Effects of leucine-rich protein supplements in older adults with sarcopenia: A systematic review and meta-analysis of randomized controlled trials

This study examined whether leucine-rich protein supplements improve muscle strength, mass, and performance in sarcopenic older adults.We searched PubMed-Medline, Embase, and Cochrane Library databases for randomized controlled trials comparing leucine-rich protein supplements with a control intervention in sarcopenic older adults. A pairwise meta-analysis using a fixed-effects model was performed. The primary outcome of interest was muscle strength regardless of the measures used. Effect sizes were computed as standardized mean differences (SMDs) with 95% confidence intervals (CIs).Six randomized controlled trials including a total of 699 participants were retrieved. Leucine-rich protein supplements improved participants' overall muscle strength, mass, and performance compared to the control group (SMD = 0.939; 95% CI, 0.440-1.438; P < 0.001). As the primary outcome, muscle strength improved significantly in the leucine group (SMD = 0.794; 95% CI, 0.104-1.485; P = 0.024).Leucine-rich protein supplements improve muscle strength in sarcopenic older adults. They may be suggested in nutritional treatment of sarcopenia.