Wilkinson Sarah B, Tarnopolsky Mark A, Macdonald Maureen J, Macdonald Jay R, Armstrong David, Phillips Stuart M
Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Canada.
Am J Clin Nutr. 2007 Apr;85(4):1031-40. doi: 10.1093/ajcn/85.4.1031.
Resistance exercise leads to net muscle protein accretion through a synergistic interaction of exercise and feeding. Proteins from different sources may differ in their ability to support muscle protein accretion because of different patterns of postprandial hyperaminoacidemia.
We examined the effect of consuming isonitrogenous, isoenergetic, and macronutrient-matched soy or milk beverages (18 g protein, 750 kJ) on protein kinetics and net muscle protein balance after resistance exercise in healthy young men. Our hypothesis was that soy ingestion would result in larger but transient hyperaminoacidemia compared with milk and that milk would promote a greater net balance because of lower but prolonged hyperaminoacidemia.
Arterial-venous amino acid balance and muscle fractional synthesis rates were measured in young men who consumed fluid milk or a soy-protein beverage in a crossover design after a bout of resistance exercise.
Ingestion of both soy and milk resulted in a positive net protein balance. Analysis of area under the net balance curves indicated an overall greater net balance after milk ingestion (P < 0.05). The fractional synthesis rate in muscle was also greater after milk consumption (0.10 +/- 0.01%/h) than after soy consumption (0.07 +/- 0.01%/h; P = 0.05).
Milk-based proteins promote muscle protein accretion to a greater extent than do soy-based proteins when consumed after resistance exercise. The consumption of either milk or soy protein with resistance training promotes muscle mass maintenance and gains, but chronic consumption of milk proteins after resistance exercise likely supports a more rapid lean mass accrual.
抗阻运动通过运动与进食的协同作用导致肌肉蛋白质净增加。由于餐后高氨基酸血症模式不同，不同来源的蛋白质在支持肌肉蛋白质增加的能力上可能存在差异。
我们研究了在健康年轻男性抗阻运动后，摄入等氮、等能量且宏量营养素匹配的大豆或牛奶饮品（18克蛋白质，750千焦）对蛋白质动力学和肌肉蛋白质净平衡的影响。我们的假设是，与牛奶相比，摄入大豆会导致更大但短暂的高氨基酸血症，而牛奶会因较低但持续时间较长的高氨基酸血症促进更大的净平衡。
在一组年轻男性进行一轮抗阻运动后，采用交叉设计让他们饮用液态牛奶或大豆蛋白饮品，然后测量动静脉氨基酸平衡和肌肉蛋白质合成率。
摄入大豆和牛奶均导致蛋白质净平衡为正。对净平衡曲线下面积的分析表明，摄入牛奶后总体净平衡更大（P<0.05）。饮用牛奶后肌肉的蛋白质合成率（0.10±0.01%/小时）也高于饮用大豆后（0.07±0.01%/小时；P=0.05）。
抗阻运动后饮用时，乳类蛋白比大豆蛋白更能促进肌肉蛋白质增加。抗阻训练时摄入牛奶或大豆蛋白均可促进肌肉量的维持和增加，但抗阻运动后长期摄入乳类蛋白可能有助于更快速地增加瘦体重。
