Nutritional Epidemiology Program, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, 711 Washington Street, Room 901D, Boston, MA 02111, USA.
Br J Nutr. 2013 Apr 14;109(7):1294-303. doi: 10.1017/S0007114512003133. Epub 2012 Aug 2.
Resistance training is recognised as a good strategy for retarding age-related declines in muscle mass and strength. Recent studies have also highlighted the potential value of protein intakes in excess of present recommendations. The roles that leisure-time physical activity and protein quality play in the preservation of skeletal muscle during ageing, and how such influences interact in free-living people are unclear. We sought to clarify these issues using data collected on 2425 participants aged ≥ 50 years in the US National Health and Nutrition Examination Survey (2003-2006). We estimated subjects' usual intakes of total protein and beef from two 24 h diet recalls and computed the appendicular skeletal muscle mass index from anthropometric measures. Participants self-reported their physical activity levels. Analyses accounted for demographic factors and smoking. The association between muscle-strengthening activity and the appendicular skeletal muscle mass index varied with protein intake. Furthermore, among obese subjects with protein intakes < 70 g/d, those who performed such activities had a lower appendicular skeletal muscle mass index than those who were physically inactive. Protein intakes above the present recommendations were associated with benefits to obese subjects only. The appendicular skeletal muscle mass index of non-obese subjects who performed vigorous aerobic activities was consistently high; in obese subjects, it varied with protein intake. High-protein intake was associated with a modest increase in the appendicular skeletal muscle mass index in non-obese, physically inactive subjects. The present findings reinforce the idea that muscle-strengthening exercise preserves muscle when combined with adequate dietary protein. Vigorous aerobic activity may also help.
抗阻训练被认为是延缓与年龄相关的肌肉质量和力量下降的好策略。最近的研究还强调了蛋白质摄入量超过目前建议的潜在价值。在衰老过程中，休闲时间体力活动和蛋白质质量在维持骨骼肌中的作用，以及这些影响如何在自由生活的人中相互作用尚不清楚。我们试图使用美国国家健康和营养检查调查（2003-2006 年）中≥50 岁的 2425 名参与者收集的数据来澄清这些问题。我们从两次 24 小时饮食回忆中估计了受试者的总蛋白质和牛肉的通常摄入量，并根据人体测量指标计算了四肢骨骼肌质量指数。参与者自我报告了他们的身体活动水平。分析考虑了人口统计学因素和吸烟情况。肌肉强化活动与四肢骨骼肌质量指数之间的关联随蛋白质摄入量而变化。此外，在蛋白质摄入量<70g/d 的肥胖受试者中，与不活跃的人相比，进行此类活动的人的四肢骨骼肌质量指数较低。超过目前建议的蛋白质摄入量仅与肥胖受试者有关。进行剧烈有氧运动的非肥胖受试者的四肢骨骼肌质量指数始终较高；在肥胖受试者中，它随蛋白质摄入量而变化。高蛋白质摄入量与非肥胖、不活跃的受试者四肢骨骼肌质量指数的适度增加有关。本研究结果进一步证实了肌肉强化运动与充足的饮食蛋白质结合可以保持肌肉的观点。剧烈的有氧运动也可能有所帮助。
