Study shows that the type and quantity of protein consumed significantly impact muscle building in older men.

Writing in The American Journal of Clinical Nutrition, researchers led by Stuart Phillips of the Exercise Metabolism Research Group at McMaster University compared the effects of additional whey, pea, and collagen protein supplementation on muscle protein synthesis (MPS) in a group of 30 men between the ages of 65 and 80.

“We aimed to determine the impact of consuming higher- versus lower-quality protein supplements above the recommended dietary allowance (RDA) on integrated MPS rates,” they wrote. “We hypothesized that increasing total protein intake above the RDA, regardless of the source, would support higher integrated rates of myofibrillar protein synthesis.”

The study was supported by a research contract from French food company Roquette Frères.

Protein and skeletal muscle mass beyond RDA

Skeletal muscle mass is determined predominantly by feeding- and activity-induced fluctuations in muscle protein synthesis (MPS), the study noted. Older adults have a lower MPS response to protein ingestion (age-related anabolic resistance) that contributes to the progression of age-related muscle loss (sarcopenia), which increases the risk of mobility issues, falls, fractures, hospitalization, and frailty.

“The United States–Canadian dietary guidelines recommended dietary allowance (RDA) for protein intake remains the same for all adults (0.8 g/kg/d), regardless of age, with little reference to source or pattern of intake,” the researchers wrote. “Several factors have been proposed to affect older adults’ MPS response, including quantity (per-meal protein ‘dose’), quality, and distribution of protein intake.”