School of Public Health, Physiotherapy and Sport Science, University College Dublin, Dublin, Ireland.
Department of Biomedical Sciences, University of Padua, Padua, Italy.
Am J Clin Nutr. 2021 Jun 1;113(6):1411-1427. doi: 10.1093/ajcn/nqaa449.
Leucine-enriched protein (LEU-PRO) and long-chain (LC) n-3 (ω-3) PUFAs have each been proposed to improve muscle mass and function in older adults, whereas their combination may be more effective than either alone.
The impact of LEU-PRO supplementation alone and combined with LC n-3 PUFAs on appendicular lean mass, strength, physical performance and myofibrillar protein synthesis (MyoPS) was investigated in older adults at risk of sarcopenia.
This 24-wk, 3-arm parallel, randomized, double-blind, placebo-controlled trial was conducted in 107 men and women aged ≥65 y with low muscle mass and/or strength. Twice daily, participants consumed a supplement containing either LEU-PRO (3 g leucine, 10 g protein; n = 38), LEU-PRO plus LC n-3 PUFAs (0.8 g EPA, 1.1 g DHA; LEU-PRO+n-3; n = 38), or an isoenergetic control (CON; n = 31). Appendicular lean mass, handgrip strength, leg strength, physical performance, and circulating metabolic and renal function markers were measured pre-, mid-, and postintervention. Integrated rates of MyoPS were assessed in a subcohort (n = 28).
Neither LEU-PRO nor LEU-PRO+n-3 supplementation affected appendicular lean mass, handgrip strength, knee extension strength, physical performance or MyoPS. However, isometric knee flexion peak torque (treatment effect: -7.1 Nm; 95% CI: -12.5, -1.8 Nm; P < 0.01) was lower postsupplementation in LEU-PRO+n-3 compared with CON. Serum triacylglycerol and total adiponectin concentrations were lower, and HOMA-IR was higher, in LEU-PRO+n-3 compared with CON postsupplementation (all P < 0.05). Estimated glomerular filtration rate was higher and cystatin c was lower in LEU-PRO and LEU-PRO+n-3 postsupplementation compared with CON (all P < 0.05).
Contrary to our hypothesis, we did not observe a beneficial effect of LEU-PRO supplementation alone or combined with LC n-3 PUFA supplementation on appendicular lean mass, strength, physical performance or MyoPS in older adults at risk of sarcopenia. This trial was registered at clinicaltrials.gov as NCT03429491.
亮氨酸富集蛋白（LEU-PRO）和长链（LC）n-3（ω-3）多不饱和脂肪酸（PUFAs）均被提议用于改善老年人的肌肉质量和功能，而两者的结合可能比单独使用任何一种更有效。
本研究旨在探讨 LEU-PRO 补充剂单独使用和与 LC n-3 PUFAs 联合使用对肌肉减少症风险老年人的四肢瘦体重、力量、身体表现和肌原纤维蛋白合成（MyoPS）的影响。
这是一项为期 24 周、3 臂平行、随机、双盲、安慰剂对照试验，纳入了 107 名年龄≥65 岁、肌肉量和/或力量较低的男性和女性。参与者每日两次摄入含有 LEU-PRO（3 克亮氨酸，10 克蛋白质；n=38）、LEU-PRO 加 LC n-3 PUFAs（0.8 克 EPA、1.1 克 DHA；LEU-PRO+n-3；n=38）或等能量对照（CON；n=31）的补充剂。在干预前、中期和后期测量四肢瘦体重、握力、腿部力量、身体表现以及循环代谢和肾功能标志物。在亚组（n=28）中评估肌原纤维蛋白合成的综合速率。
LEU-PRO 或 LEU-PRO+n-3 补充剂均未影响四肢瘦体重、握力、膝关节伸展力量、身体表现或肌原纤维蛋白合成。然而，与 CON 相比，LEU-PRO+n-3 补充剂后等长膝关节屈曲峰值扭矩（治疗效果：-7.1 Nm；95%CI：-12.5，-1.8 Nm；P<0.01）较低。与 CON 相比，LEU-PRO+n-3 补充剂后血清三酰甘油和总脂联素浓度降低，HOMA-IR 升高（均 P<0.05）。与 CON 相比，LEU-PRO 和 LEU-PRO+n-3 补充剂后估算的肾小球滤过率升高，胱抑素 c 降低（均 P<0.05）。
与我们的假设相反，我们没有观察到 LEU-PRO 补充剂单独使用或与 LC n-3 PUFAs 补充剂联合使用对肌肉减少症风险老年人的四肢瘦体重、力量、身体表现或肌原纤维蛋白合成有有益影响。本研究在 clinicaltrials.gov 上注册为 NCT03429491。
