SIB# 374 Protein Supplements, Muscle Mass and Strength
The Study: A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults.
a. In this article the authors performed a systematic review, a metaanalysis and meta-regression.
b. They wusged to determine if adding protein to the diet improved muscle gain and strength of individuals who engaged in resistance training.
c. The studies they looked at were randomized controlled trials.
d. The study had to have the participants perform the resistance exercise training at least two times a week and at least one group in that study was given additional protein.
e. They found 49 studies that met their criteria. (note: 14 of these studies had only female subjects.)
f. The included studies contained a total of 1863 subjects.
g. They found that supplementation of protein increased both one-repetition-maximum strength and fat free mass.
h. The authors made the following statement, “Here we provide significant insight (using 42 study arms including 723 young and old participants with protein intakes ranging from 0.9 g protein/kg/day to 2.4 g protein/kg/ day) by reporting an unadjusted plateau in RET-induced gains [resistance exercise training] in FFM [fat free mass] at 1.62 g protein/kg/day (95% CI: 1.03 to 2.20).” [1.62grams of protein per kilogram of body weight a day.]
i. “Based on limited data we observed no overtly apparent sex-based differences…” They noted that there had been far less study of females.
Take Home: Protein supplementation coupled with resistance training increased lean body mass up to a total protein consumption of 1.62 g protein per day per kilogram (0.73 g per pound) of body weight. Supplementation in excess of this amount did not appear to have any beneficial effect.
I think most of us know you need to have protein as a building block of muscle in order to show improvement with resistance training. But you will note that there was a limit to the amount of protein intake that was effective. Also I was heartened to see that there are studies (although not enough) on female subjects related to this field. I have always thought that the best athlete in my high school was a female. Unfortunately her opportunities were quite limited at that time. (No, they did not write on clay tablets when I was in high school. We had papyrus.)
Reviewer: Roger Coleman DC
Editor: Mark R. Payne DC
Reference: Morton RW, Murphy KT, McKellar SR et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med 2018 Mar;52(6):376-384. doi: 10.1136/bjsports-2017-097608. Epub 2017 Jul 11.
Link to Abstract: https://www.ncbi.nlm.nih.gov/pubmed/28698222