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DuPont Nutrition & Health shares new research results finding both whey protein alone or a blend of whey and soy proteins may help curb muscle loss in older men.
DuPont Nutrition & Health (Madison, WI) has shared new study results suggesting a blend of whey and soy proteins may help curb key signs of muscle loss in older men. The soy/whey blend was also found to induce similar results as whey protein taken alone in improving signs of age-related muscle loss, which is also known as sarcopenia.
Writing in The Journal of Nutrition, researchers studied men aged 55–75 who were randomized in a double-blind, controlled trial to consume either 30 grams of whey protein isolate or 30 grams of a blend containing 25% DuPont Danisco SUPRO soy protein, 25% whey, and 50% casein. All participants performed leg extension exercises one hour before supplementation, which consisted of eight sets of 10 repetitions at 70% one-repetition maximum power.
To measure the effect of the administrations on muscle-protein metabolism, researchers took muscle biopsies before the resistance exercise and up to five hours after exercise. They used stable isotope methods to monitor breakdown and synthesis of muscle tissue, including measuring for amino-acid concentrations. They also measured how the administrations enhanced signaling of mechanistic target of rapamycin complex 1 (mTORC1), a complex responsible for controlling protein synthesis, through immunoblotting.
Researchers report that soy and dairy blend induced amino-acid delivery to muscle tissue, induced muscle protein synthesis, and activated a key pathway that imitates muscle protein turnover. Compared to the group taking whey protein alone, the protein blend group experienced a similar increase to amino-acid concentrations, mTORC1 signaling, post-exercise fractional synthesis rate, and fractional breakdown rate-indicating the two treatments induced similar responses to muscle protein metabolism in older men after exercise.
“These data add new evidence for the use of whey or soy-dairy [protein blends] as targeted nutritional interventions to counteract sarcopenia,” researchers concluded.
In an announcement for the study, DuPont notes that this is the first study to investigate the effects of a protein blend on muscle protein metabolism in aging individuals, which it says “is more representative of how people consume protein,” rather than just relying on a single protein source.
“The study adds to our understanding of the response of the aging population to preventive measures, diet, and resistance exercise,” DuPont says. “The similarity between the two protein treatment groups for muscle protein synthesis and mTORC1 signaling demonstrates the role of consuming high-quality proteins for prevention of conditions associated with age.”
Nutritional Outlook Magazine
Borack MS et al., “Soy-dairy protein blend or whey protein isolate ingestion induces similar postexercise muscle mechanistic target of rapamycin complex 1 signaling and protein synthesis responses in older men,” The Journal of Nutrition. Published online October 26, 2016.