Animal Protein versus Plant Protein in Supporting Lean Mass and Muscle Strength: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 33670701 · doi:10.3390/nu13020661
What was done
Authors conducted a systematic review and meta-analysis of randomized controlled trials to evaluate the effects of animal versus plant protein on lean mass and muscle strength, along with the influence of resistance exercise training (RET) and age. Databases searched were PubMed, Embase, Scopus, and CINAHL Plus with Full Text. Across 3,081 screened articles, 18 articles were selected for the systematic review and 16 were included in the meta-analysis. Baseline and intervention protein intakes were generally above the recommended dietary allowance.
What was found
Protein source did not affect changes in absolute lean mass or muscle strength overall, but animal protein had a favoring effect on percent lean mass. Resistance exercise training did not alter these findings. In younger adults (<50 years), animal protein intake led to significantly greater gains in absolute lean mass (weighted mean difference [WMD] 0.41 kg; 95% CI 0.08 to 0.74) and percent lean mass (WMD 0.50%; 95% CI 0.00 to 1.01).
Why it matters
This review indicates that plant protein can support muscle strength and absolute lean mass similarly to animal protein in adequate diets, though animal protein may have a slight advantage for lean mass accretion in younger adults.
Limits
The total number of human participants across studies is not stated in the abstract. Quantitative effect estimates and confidence intervals for the overall main effects are omitted, as are details regarding specific protein types, intervention durations, and study quality or risk of bias.
Cited by
- context There is no difference in muscle size or strength outcomes between plant and animal protein diets.