Benefits of Whey Protein on Muscle
Whey protein is a high-quality dairy protein that contains all the amino acids the body requires for muscle protein synthesis. Evidence suggests that whey protein, found naturally in milk, increases muscle protein synthesis which in combination with resistance exercise can improve body composition. Below are summaries of recent studies that further explain the benefits of whey protein.
Whey protein is one of the best sources of branched-chain amino acids (BCAA), including leucine, which has been shown to independently stimulate muscle protein synthesis
This review article shares data from the USDA Food Composition Tables that show dairy products are rich sources of BCAAs and whey protein isolate is a leading source of leucine. The author cites several studies that give increasing evidence that BCAAs, specifically leucine, have a unique affect on metabolism that includes regulation of muscle protein synthesis and glucose homeostasis. The impact of BCAAs is proportional to availability and dietary intake.
Layman DK. The role of leucine in weight loss diets and glucose homeostasis. Journal of Nutrition. 2003;133:261S-267S.
Consuming whey protein after resistance exercise can stimulate protein synthesis
Ingestion of amino acids is known to stimulate protein synthesis and result in a positive net muscle protein balance. Tipton and colleagues investigated whether consumption of casein or whey proteins have a similar beneficial effect following resistance exercise. Healthy untrained volunteers were randomly assigned to receive a drink containing either: (1) 20 g casein (N=7); (2) 20 g whey protein (N=9); or (3) placebo (N = 7) one-hour after performing a bout of resistance training. Leg muscle biopsies were taken to measure net muscle protein balance.
Consumption of both casein and whey proteins were found to bring about a similar positive net muscle protein balance, indicating that whole protein