Center for Translational Research in Aging & Longevity, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4253, USA.
Clin Nutr. 2013 Apr;32(2):309-13. doi: 10.1016/j.clnu.2012.11.018. Epub 2012 Dec 1.
Several recent publications indicate that the maximum stimulation of muscle protein fractional synthetic rate occurs with intake of 20-30 g protein. This finding has led to the concept that there is a maximal anabolic response to protein intake with a meal, and that the normal amount of protein eaten with dinner will generally exceed the maximally-effective intake of protein. However, protein breakdown has not been taken into account when evaluating the anabolic response to protein intake. Protein anabolism occurs only when protein synthesis exceeds protein breakdown. Higher protein intakes when protein synthesis is maximized is characterized by suppressed protein breakdown and via that mechanism leads to a greater anabolic response. This explains why when net protein synthesis is measured, the relationship between amino acid availability and net gain remains linear, without any apparent plateau of effect at higher levels of availability. We conclude that there is no practical upper limit to the anabolic response to protein or amino acid intake in the context of a meal.
最近的几项研究表明，摄入 20-30 克蛋白质可以最大程度地刺激肌肉蛋白质合成率。这一发现导致了这样一种概念，即每餐摄入蛋白质会产生最大的合成代谢反应，而晚餐时摄入的正常蛋白质量通常会超过最大有效蛋白质摄入量。然而，在评估蛋白质摄入的合成代谢反应时，并没有考虑到蛋白质的分解。只有当蛋白质合成超过蛋白质分解时，蛋白质才会合成。当蛋白质合成最大化时，较高的蛋白质摄入量的特点是抑制蛋白质分解，并且通过这种机制导致更大的合成代谢反应。这就解释了为什么当测量净蛋白质合成时，氨基酸可用性与净收益之间的关系仍然是线性的，在更高的可用性水平上没有明显的效果平台。我们得出结论，在进餐的情况下，蛋白质或氨基酸摄入的合成代谢反应没有实际的上限。
