Protein shake users should take note of a study conducted at the University of Texas Medical Branch and published in Journal of Applied Physiology. Results from lead researcher Blake B. Rasmussen’s study show that consuming a blend of soy and dairy proteins (both casein and whey) is optimal for building muscle mass. “This study sheds new light on how unique combinations of proteins, as opposed to single protein sources, are important for muscle recovery following exercise and help extend amino acid availability, further promoting muscle growth,” said Dr. Rasmussen in a press release.
It was previously suggested that soy-dairy blends extend muscle protein synthesis compared to only whey (dairy) protein alone. This study established the importance of the combination’s ability to deliver amino acids to rebuilding muscles for hours post-exercise, as the digestion rates of soy and dairy proteins are different. The finding was made through a double-blind, randomized clinical trial funded by DuPont Nutrition and Health that enlisted 16 young adults ages 19 to 30. Participates performed high-intensity resistance exercises and were then given DuPont Danisco SUPRO soy protein with 50% caseinate and 25% whey protein isolate an hour after exercise. Muscle biopsies were used to measure amino acid levels and muscle protein synthesis at rest and three and five hours post-exercise. Although phenylalanine transport into muscle was similar between the group receiving the blend and the group receiving whey protein alone, the blend prolonged the positive net phenylalanine balance to five hours.
“Because of the increased demand for high-quality protein, this study provides critical insight for the food industry as a whole, and the sports nutrition market in particular,” said Greg Paul, global marketing director for DuPont Nutrition and Health. “With more and more consumers recognizing the importance of protein for their overall health and well-being, the results of this study have particular relevance to a large segment of the population, from the serious sports and fitness enthusiast to the mainstream consumer.” Soon, consumers will know the effect of the protein blends on long-term muscle mass and strength as a result of more work being conducted by the authors.