GALVESTON — Drinking a beverage made from a blend of soy and dairy proteins after exercise can increase muscle growth, according to a study now online in the Journal of Nutrition.
The study is the first to look at the effects of this combination of proteins on muscle protein synthesis.
University of Texas Medical Branch researchers worked with human subjects who drank a protein blend of soy, whey and casein — a protein derived from milk — after performing resistance exercise.
The three protein sources have complementary amino-acid profiles since they are digested at different rates. Results showed a more prolonged delivery of amino acids to muscles and extended muscle protein synthesis when subjects consumed the blend compared to a single source of protein alone.
“Sources of high-quality protein each have individual characteristics thought to offer unique advantages for muscle growth,” said Blake Rasmussen, interim chairman of the Department of Nutrition and Metabolism at UTMB and principal investigator of the study.
“This is the first study to test the effects of combining soy with the dairy proteins whey and casein for promotion of lean body mass gain.”
Researchers based the composition of the protein blend on results from a recent preclinical study that demonstrated enhanced muscle protein synthesis in rats compared to another blend of soy or whey protein sources alone.
The study used a blend of 25 percent isolated soy protein, 25 percent isolated whey protein and 50 percent caseinate.