School of Health Sciences, Örebro University, 702 81 Örebro, Sweden.
Nutrients. 2018 Aug 24;10(9):1156. doi: 10.3390/nu10091156.
The role of dietary protein intake on muscle mass and physical function in older adults is important for the prevention of age-related physical limitations. The aim of the present study was to elucidate links between dietary protein intake and muscle mass and physical function in older women meeting current guidelines of objectively assessed physical activity. In 106 women (65 to 70 years old), protein intake was assessed using a 6-day food record and participants were classified into high and low protein intake groups using two Recommended Dietary Allowance (RDA) thresholds (0.8 g·kg bodyweight (BW) and 1.1 g·kg BW). Body composition, aerobic fitness, and quadriceps strength were determined using standardized procedures, and self-reported physical function was assessed using the SF-12 Health Survey. Physical activity was assessed by accelerometry and self-report. Women below the 0.8 g·kg BW threshold had a lower muscle mass ( < 0.05) with no differences in physical function variables. When based on the higher RDA threshold (1.1 g·kg BW), in addition to significant differences in muscle mass, women below the higher threshold had a significantly ( < 0.05) higher likelihood of having physical limitations. In conclusion, the present study supports the RDA threshold of 0.8 g·kg BW of proteins to prevent the loss of muscle mass and emphasizes the importance of the higher RDA threshold of at least 1.1 g·kg BW to infer additional benefits on constructs of physical function. Our study also supports the role of protein intake for healthy ageing, even in older adults meeting guidelines for physical activity.
膳食蛋白质摄入量对老年人肌肉质量和身体功能的作用对于预防与年龄相关的身体功能限制非常重要。本研究的目的是阐明在满足当前客观评估身体活动指南的老年女性中，膳食蛋白质摄入量与肌肉质量和身体功能之间的联系。在 106 名女性（65 至 70 岁）中，使用 6 天的食物记录评估蛋白质摄入量，并使用两个推荐膳食允许量（RDA）阈值（0.8 g·kg 体重（BW）和 1.1 g·kg BW）将参与者分为高和低蛋白质摄入量组。使用标准化程序确定身体成分、有氧健身和股四头肌力量，使用 SF-12 健康调查评估自我报告的身体功能。通过加速度计和自我报告评估身体活动。低于 0.8 g·kg BW 阈值的女性肌肉质量较低（<0.05），身体功能变量无差异。当基于较高的 RDA 阈值（1.1 g·kg BW）时，除了肌肉质量的显著差异外，低于较高阈值的女性发生身体功能限制的可能性显著更高（<0.05）。总之，本研究支持 0.8 g·kg BW 的 RDA 蛋白质阈值来预防肌肉质量的损失，并强调了至少 1.1 g·kg BW 的较高 RDA 阈值对身体功能结构推断额外益处的重要性。我们的研究还支持蛋白质摄入量对健康衰老的作用，即使是在满足身体活动指南的老年成年人中。
