Anti-sarcopenic effect of leucine-enriched branched-chain amino acid supplementation among elderly chronic kidney disease patients: a double-blinded randomized controlled trial

抄録

Abstract
Background Leucine, branched-chain amino acids (BCAA), represents an effective nutritional strategy to augment skeletal muscle mass in aging population. The study aimed to determine the effect of oral leucine-enriched BCAA supplementation on muscle mass, biomarkers of muscle synthesis and physical performance among elderly patients with chronic kidney disease (CKD). Methods A randomized controlled trial study was performed among patients with CKD stage III and IV aged over 65 year. Eligible participants were randomly assigned to either oral 4.5 g/day of leucine in mixed BCAA supplement (N = 29) or placebo (N = 26) in the same manner for 12 weeks. Blood chemistry, serum insulin growth factor-1 (IGF-1), serum myostatin, muscle mass using dual energy X-ray absorptiometry were measured at start and end of the intervention. Three-day food record was documented and reviewed by a dietitian. All participants were monitored for functional capacity using the handgrip and 6-minute walk tests during the study. Results Fifty-five patients (33 males) with mean age of 75.4 ± 5.2 years were enrolled. Daily protein and calorie intake during the study were similar in both groups. After the end of the study, lean muscle mass was significantly increased in the leucine group compared with that of the placebo group (0.4 kg (95% CI 0.1 to 0.7) vs. -0.2 kg; 95% CI -0.6 to 0.2) kg, P = 0.010, respectively). Also, statistically significant differences were noted in percentage of changed in muscle mass at 12 weeks between the leucine and placebo groups (1.0 ± 1.8 vs. -0.5 ± 2.6%, P = 0.014). However, muscle strength determined by handgrip and 6-minute walk tests, serum myostatin and IGF-1 did not significantly differ between the two groups. No serious adverse event was observed during the study. Conclusions In our study, 12 weeks of oral supplement with leucine-enriched BCAA resulted in increasing muscle mass, However, the treatment dose showed no benefit on biomarkers of muscle activity, functional capacity and adverse reaction among elderly patients with CKD.