Nutritional Physiology Research Group, Public Health and Sport Sciences, Faculty of Health and Life Sciences, University of Exeter, Exeter, UK.
Physiol Rep. 2023 Aug;11(15):e15775. doi: 10.14814/phy2.15775.
Dietary protein ingestion augments post (resistance) exercise muscle protein synthesis (MPS) rates. It is thought that the dose of leucine ingested within the protein (leucine threshold hypothesis) and the subsequent plasma leucine variables (leucine trigger hypothesis; peak magnitude, rate of rise, and total availability) determine the magnitude of the postprandial postexercise MPS response.
A quantitative systematic review was performed extracting data from studies that recruited healthy adults, applied a bout of resistance exercise, ingested a bolus of protein within an hour of exercise, and measured plasma leucine concentrations and MPS rates (delta change from basal).
Ingested leucine dose was associated with the magnitude of the MPS response in older, but not younger, adults over acute (0-2 h, r = 0.64, p = 0.02) and the entire postprandial (>2 h, r = 0.18, p = 0.01) period. However, no single plasma leucine variable possessed substantial predictive capacity over the magnitude of MPS rates in younger or older adults.
Our data provide support that leucine dose provides predictive capacity over postprandial postexercise MPS responses in older adults. However, no threshold in older adults and no plasma leucine variable was correlated with the magnitude of the postexercise anabolic response.
饮食蛋白质摄入可增加运动后（抗阻）肌肉蛋白质合成（MPS）速率。人们认为，蛋白质中摄入的亮氨酸剂量（亮氨酸阈值假说）和随后的血浆亮氨酸变量（亮氨酸触发假说；峰值幅度、上升速率和总可用性）决定了运动后 MPS 反应的幅度。
进行了一项定量系统评价，从招募健康成年人、进行一次抗阻运动、运动后 1 小时内摄入蛋白质冲击、测量血浆亮氨酸浓度和 MPS 率（与基础相比的变化量）的研究中提取数据。
在急性（0-2 小时，r=0.64，p=0.02）和整个餐后（>2 小时，r=0.18，p=0.01）期间，摄入亮氨酸剂量与老年人而非年轻人的 MPS 反应幅度相关。然而，在年轻或老年人中，没有单个血浆亮氨酸变量具有预测 MPS 率幅度的能力。
我们的数据提供了支持，即亮氨酸剂量可预测老年人运动后 MPS 反应的幅度。然而，在老年人中没有亮氨酸阈值，也没有血浆亮氨酸变量与运动后的合成代谢反应幅度相关。
