Department of Food and Nutrition, Hanyang University, Seoul, Republic of Korea.
Department of Family Medicine, Hanyang University College of Medicine, Seoul, Republic of Korea.
Am J Clin Nutr. 2018 Nov 1;108(5):1026-1033. doi: 10.1093/ajcn/nqy214.
Age-related loss of muscle mass and function is a major component of frailty. Nutrition supplementation with exercise is an effective strategy to decrease frailty by preventing sarcopenia, but the effect of protein alone is controversial.
The present study was performed to investigate a dose-dependent effect of protein supplementation on muscle mass and frailty in prefrail or frail malnourished elderly people.
A 12-wk double-blind randomized controlled trial was conducted in elderly subjects aged 70-85 y with ≥1 of the Cardiovascular Health Study frailty criteria and a Mini Nutritional Assessment score ≤23.5 (n = 120). Participants were randomly assigned to 1 of 3 groups: 0.8, 1.2, or 1.5 g protein · kg-1 · d-1, with concealed allocation and intention-to-treat analysis. Primary outcomes were appendicular skeletal muscle mass (ASM) and skeletal muscle mass index (SMI) measured by dual-energy X-ray absorptiometry.
After the 12-wk intervention, the 1.5-g protein · kg-1 · d-1 group had higher ASM (mean ± SD: 0.52 ± 0.64 compared with 0.08 ± 0.68 kg, P = 0.036) and SMI (ASM/weight: 0.87% ± 0.69% compared with 0.15% ± 0.89%, P = 0.039; ASM/BMI: 0.02 ± 0.03 compared with 0.00 ± 0.04, P = 0.033; ASM:fat ratio: 0.04 ± 0.11 compared with -0.02 ± 0.10, P = 0.025) than the 0.8-g protein · kg-1 · d-1 group. In addition, gait speed was improved in the 1.5-g protein · kg-1 · d-1 group compared with the 0.8-g protein · kg-1 · d-1 group (0.09 ± 0.07 compared with 0.04 ± 0.07 m/s, P = 0.039). There were no significant differences between the 1.2- and 0.8-g protein · kg-1 · d-1 groups in muscle mass and physical performance. No harmful adverse effects were observed.
The present study indicates that protein intake of 1.5 g · kg-1 · d-1 has the most beneficial effects in regard to preventing sarcopenia and frailty compared with protein intakes of 0.8 and 1.2 g · kg-1 · d-1 in prefrail or frail elderly subjects at risk of malnutrition. This trial was registered at cris.nih.go.kr as KCT0001923.
与年龄相关的肌肉质量和功能丧失是衰弱的一个主要组成部分。营养补充与运动相结合是预防肌少症从而降低衰弱的有效策略，但单独使用蛋白质的效果存在争议。
本研究旨在探讨蛋白质补充对衰弱前期或衰弱期营养不良老年人肌肉质量和衰弱的剂量依赖性影响。
在年龄为 70-85 岁、有 ≥1 项心血管健康研究衰弱标准和微型营养评估评分 ≤23.5 的老年人中进行了为期 12 周的双盲随机对照试验（n=120）。参与者被随机分配到 3 组中的 1 组：0.8、1.2 或 1.5 g 蛋白质·kg-1·d-1，采用隐蔽分组和意向治疗分析。主要结局是通过双能 X 射线吸收法测量的四肢骨骼肌质量（ASM）和骨骼肌质量指数（SMI）。
在 12 周的干预后，1.5 g 蛋白质·kg-1·d-1 组的 ASM（均值±SD：0.52±0.64 与 0.08±0.68 kg，P=0.036）和 SMI（ASM/体重：0.87%±0.69%与 0.15%±0.89%，P=0.039；ASM/BMI：0.02±0.03 与 0.00±0.04，P=0.033；ASM：脂肪比：0.04±0.11 与-0.02±0.10，P=0.025）高于 0.8 g 蛋白质·kg-1·d-1 组。此外，与 0.8 g 蛋白质·kg-1·d-1 组相比，1.5 g 蛋白质·kg-1·d-1 组的步行速度得到改善（0.09±0.07 与 0.04±0.07 m/s，P=0.039）。1.2 g 和 0.8 g 蛋白质·kg-1·d-1 组之间在肌肉质量和身体表现方面没有显著差异。未观察到有害的不良反应。
本研究表明，与 0.8 和 1.2 g·kg-1·d-1 相比，1.5 g·kg-1·d-1 的蛋白质摄入量对衰弱前期或衰弱期营养不良的老年人预防肌少症和衰弱最有益，这些老年人有发生肌少症的风险。该试验在 cris.nih.go.kr 注册为 KCT0001923。
