Biological Sciences Department, Cork Institute of Technology, Bishopstown, Cork, Republic of Ireland.
Nutr Res Rev. 2021 Jun;34(1):147-157. doi: 10.1017/S0954422420000219. Epub 2020 Sep 4.
Amino acid bioavailability is critical for muscle protein synthesis (MPS) and preservation of skeletal muscle mass (SMM). Ageing is associated with reduced responsiveness of MPS to essential amino acids (EAA). Further, the older adult population experiences anabolic resistance, leading to increased frailty, functional decline and depleted muscle mass preservation, which facilitates the need for increased protein intake to increase their SMM. This review focuses on the role of proteins in muscle mass preservation and examines the contribution of EAA and protein intake patterns to MPS. Leucine is the most widely studied amino acid for its role as a potent stimulator of MPS, though due to inadequate data little is yet known about the role of other EAA. Reaching a conclusion on the best pattern of protein intake has proven difficult due to conflicting studies. A mixture of animal and plant proteins can contribute to increased MPS and potentially attenuate muscle wasting conditions; however, there is limited research on the biological impact of protein blends in older adults. While there is some evidence to suggest that liquid protein foods with higher than the RDA of protein may be the best strategy for achieving high MPS rates in older adults, clinical trials are warranted to confirm an association between food form and SMM preservation. Further research is warranted before adequate recommendations and strategies for optimising SMM in the elderly population can be proposed.
氨基酸生物利用度对肌肉蛋白质合成（MPS）和维持骨骼肌质量（SMM）至关重要。随着年龄的增长，MPS 对必需氨基酸（EAA）的反应能力会降低。此外，老年人群体对合成代谢的反应能力降低，导致虚弱、功能下降和肌肉质量减少，这就需要增加蛋白质摄入以增加 SMM。本综述重点介绍了蛋白质在维持肌肉质量方面的作用，并探讨了 EAA 和蛋白质摄入模式对 MPS 的贡献。亮氨酸是研究最多的氨基酸之一，因为它是刺激 MPS 的有效物质，尽管由于数据不足，我们对其他 EAA 的作用还知之甚少。由于研究结果相互矛盾，因此很难确定最佳蛋白质摄入模式。动物蛋白和植物蛋白的混合物可以促进 MPS 的增加，并可能减轻肌肉减少症的状况；然而，关于蛋白质混合物对老年人的生物学影响的研究有限。虽然有一些证据表明，高于推荐摄入量（RDA）的蛋白质的液体蛋白质食品可能是提高老年人 MPS 率的最佳策略，但仍需要进行临床试验来确认食物形式与 SMM 维持之间的关联。在为老年人优化 SMM 提出足够的建议和策略之前，还需要进行进一步的研究。
