The debate is over: Protein supplements “significantly” benefit muscle mass

09 Feb 2018 --- Dietary protein supplements do significantly improve muscle strength and size when taken by healthy adults who lift weights, say McMaster scientists who analyzed dozens of research studies. According to the researchers, their analysis puts to rest any debate on whether or not such supplementation is effective. However, the effects are not as big as some supplement companies would have you believe, cautions the senior author on the paper, Stuart Phillips, a professor of kinesiology at McMaster University.

The study, published online in the British Journal of Sports Medicine, also suggests the benefits of protein supplements increase with resistance training experience but become less effective with older adults, pointing to a need for greater supplementation to reach optimal results as we age. Additionally, there is a limit to the amount of protein that is beneficial, plateauing at roughly 1.6 grams of dietary protein per kilogram of body weight per day. 

The study is the largest meta-analysis of its kind and researchers say it provides clarity after conflicting results from previous studies.

Researchers combed through thousands of studies searching for specific criteria, including randomized controlled trials, human participants and study durations of at least six weeks. In all, they analyzed 49 high-quality individual studies with 1863 participants.

In addition to muscle mass and strength gains, they also found that: the effectiveness of protein supplementation during weight training is equal in women, not affected by the protein source-a whey protein supplement versus a steak, for example-nor the time of day the protein is taken, such as at regular meal times versus post-workout. 

One thing the researchers noted was that with increasing age there was a reduced effectiveness of protein supplementation.

Robert Morton, lead author and a Ph.D. candidate at McMaster University, explains: “Older individuals are less responsive to protein. So a given dose of protein stimulates growth less in older people. The general thought now is that we should be providing more protein.”

“I think the next step would be to find out why protein supplementation is less effective in older individuals, as well as to challenge the current recommendation of 0.8 grams of protein per kilogram body weight per day. We found that double that was effective.”

“Protein intake is critical for muscle health, and there is mounting research that suggests the recommended dietary allowance, of 0.8 g protein per kg per days, is too low,” says Morton. “We will see more and more research, especially as our populations age, challenging that number.”