A new study published online in the Journal of Applied Physiology shows added benefits of drinking a blend of soy and dairy proteins after resistance exercise for building muscle mass. Researchers from the University of Texas Medical Branch (UTMB) found that using a protein blend of soy, casein, and whey after a workout prolongs the delivery of select amino acids to the muscle for an hour longer than using whey alone. The study also shows a prolonged increase in amino acid net balance across the leg during early post-exercise recovery, which suggests prolonged muscle building.

The study, conducted by researchers from UTMB in collaboration with DuPont Nutrition and Health, used a new methodology that built on an earlier study reporting that a soy-dairy blend extends muscle protein synthesis when compared to whey alone. A news release from UTMB at Galveston notes that together, these studies show that the use of soy-dairy blends can be an effective strategy for active people seeking product to support muscle health. The new study was a double-blind, randomized clinical trial that included 16 healthy subjects aged 19 to 30 years.

The new research aimed to assess if consumption of a blend of proteins with different digestion rates would prolong amino acid availability and lead to increases in muscle protein synthesis after exercise. Muscle biopsies were taken at baseline and up to 5 hours after resistance exercise. The protein sources were ingested 1 hour after exercise in both groups. The protein beverages provided to study subjects consisted of a soy-dairy blend or a single protein source.

The results of the study reveal that drinking the soy-dairy blend leads to a steady rise in amino acids and also sustained a greater positive net amino acid balance than whey. The UTMB at Galveston news release notes that further research is ongoing to identify the long-term effect on muscle mass and strength.

Source: University of Texas Medical Branch at Galveston