A Systematic Review of the Impact of Vegetarian Diets on Muscle Mass and Muscle Strength in Community-Dwelling, Healthy Adults

Abstract

Background

Loss of muscle mass and muscle strength are key characteristics of age-related muscle decline. Dietary protein is a key nutrient that supports optimal muscle health. However, there is a strong argument to reduce intake of animal protein for health and environmental reasons. The effects of vegetarian diets on determinants of muscle health are not clear. This systematic review aimed to investigate the impact of vegetarian diets on muscle mass and muscle strength.

Methods

A systematic literature search of the CINAHL, Medline, Scopus and Web of Science Core Collection databases, as well as the Cochrane Central Register of Controlled Trials, was conducted according to PRISMA guidelines. Studies reporting the effects of vegetarian diets on muscle mass and strength were analysed.

Results

A total of three interventions and 11 observational studied were eligible to be included (n = 14) in this review. Five of the 12 studies that reported muscle mass found no difference in muscle mass between participants consuming an omnivorous versus vegetarian diet. One observational study reported higher muscle mass for vegetarians. Of the studies that reported muscle strength (n = 5), three reported no difference between participants consuming an omnivorous and vegetarian diet.

Conclusions

Half of the included studies reported no difference in muscle mass or strength between vegetarians and omnivores. Further high-quality studies are needed to better understand the relationship between vegetarian diets and determinants of muscle health.