Effects of Leucine Supplementation in Older Adults with Sarcopenia: A Meta-Analysis

Background and Objectives: Research on the impact of leucine on older sarcopenic patients is scarce, and investigations on this subject have led to contradictory findings in the literature. Our goal was to compile data from the available studies in the literature to explore the effect of leucine supplementation on parameters associated with sarcopenia in elderly individuals. Methods: The meta-analysis included older persons over 65 years of age who were recruited on the basis of the European Working Group on Sarcopenia in Older People sarcopenia criteria. Studies that were included were those in which at least one sarcopenia criterion was measured, including grip strength, appendicular skeletal muscle mass/height², gait speed, and the short physical performance battery index. Results: The meta-analysis included ten randomized controlled trials and one prospective study. The leucine group included 566 participants, whereas the placebo group included 567 patients. Patients receiving leucine and patients receiving a placebo had significantly different handgrip (p = 0.03), appendicular skeletal muscle mass/height² (p = 0.0.2), and gait speed (p = 0.008). Patients received a high dosage of leucine, and there was a significant difference in the appendicular skeletal muscle mass/height² (p = 0.02) and gait speed (p = 0.01) between the high dosage of the leucine group and the control group. When vitamin D was combined with leucine, the appendicular skeletal muscle mass/height² (p = 0.03) significantly differed between the leucine group receiving vitamin D and the control group. Conclusions: Low-quality evidence was found that older sarcopenic patients receiving leucine may show trends toward improved skeletal muscle strength, skeletal muscle quality, and physical performance. The capacity of leucine supplementation to have a beneficial therapeutic impact in older sarcopenic individuals is restricted when it is used alone without concurrent additional therapy.