Department of Nutrition Science, Purdue University, 700 W State St, West Lafayette, IN 47907, USA.
Department of Pediatrics, University of Arkansas for Medical Sciences, 4301 W Markham St, Little Rock, AR 72205, USA.
Nutrients. 2020 May 16;12(5):1441. doi: 10.3390/nu12051441.
There is a shift in thinking about dietary protein requirements from daily requirements to individual meal requirements. Per meal, stimulation of muscle protein synthesis has a saturable dose relationship with the quantity of dietary protein consumed. Protein intake above the saturable dose does not further contribute to the synthetic response; the "excess" amino acids are predominantly oxidized. Given that daily dietary protein intake is finite, finding protein distribution patterns that both reduce amino acid oxidation and maximize their contribution towards protein synthesis (in theory improving net balance) could be "optimal" and is of practical scientific interest to promote beneficial changes in skeletal muscle-related outcomes. This article reviews both observational and randomized controlled trial research on the protein distribution concept. The current evidence on the efficacy of consuming an "optimal" protein distribution to favorably influence skeletal muscle-related changes is limited and inconsistent. The effect of protein distribution cannot be sufficiently disentangled from the effect of protein quantity. Consuming a more balanced protein distribution may be a practical way for adults with marginal or inadequate protein intakes (<0.80 g·kg·d) to achieve a moderately higher total protein intake. However, for adults already consuming 0.8-1.3 g·kg·d, the preponderance of evidence supports that consuming at least one meal that contains sufficient protein quantity to maximally stimulate muscle protein synthesis, independent of daily distribution, is helpful to promote skeletal muscle health.
关于膳食蛋白质需求，人们的思维正在从每日需求转向每餐需求转变。每餐，肌肉蛋白质合成的刺激与摄入的膳食蛋白质量呈饱和剂量关系。超过饱和剂量的蛋白质摄入量不会进一步促进合成反应；“多余”的氨基酸主要被氧化。由于每日膳食蛋白质摄入量是有限的，找到既能减少氨基酸氧化又能最大限度地促进蛋白质合成（理论上提高净平衡）的蛋白质分布模式可能是“最佳”的，并且从实际科学的角度来看，促进与骨骼肌相关的结果的有益变化是很有意义的。本文综述了关于蛋白质分布概念的观察性和随机对照试验研究。目前关于摄入“最佳”蛋白质分布以有利影响骨骼肌相关变化的功效的证据有限且不一致。蛋白质分布的效果不能与蛋白质数量的效果充分区分开来。对于蛋白质摄入量处于边缘或不足（<0.80 g·kg·d）的成年人来说，更均衡的蛋白质分布可能是一种实现适度更高总蛋白质摄入量的实用方法。然而，对于已经摄入 0.8-1.3 g·kg·d 的成年人来说，大多数证据支持，摄入至少一顿含有足够蛋白质量以最大限度地刺激肌肉蛋白质合成的餐食，独立于每日分布，有助于促进骨骼肌健康。
