The Skeletal Muscle Anabolic Response to Plant- versus Animal-Based Protein Consumption.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing mechanistic and comparative evidence without systematic review methodology
PubMed 26224750 · doi:10.3945/jn.114.204305
What was done
This review examined evidence regarding the skeletal muscle protein synthetic response to plant-based proteins (primarily soy and wheat) compared with animal-based proteins. It evaluated potential physiological mechanisms for differences in anabolic properties—including digestibility, splanchnic extraction, urea synthesis, and essential amino acid/leucine content—and summarized dietary strategies proposed to augment plant protein anabolism.
What was found
The abstract reports no numerical values or effect sizes. It notes that ingestion of soy and wheat protein results in a lower muscle protein synthetic response compared with several animal proteins. Mechanisms identified include lower digestibility, greater splanchnic amino acid extraction and urea synthesis, lower leucine content, and relative deficits in specific essential amino acids. Potential compensatory strategies identified include amino acid fortification (methionine, lysine, leucine), selective plant breeding, consuming higher total protein amounts, and combining complementary plant sources.
Why it matters
This review outlines the physiological constraints of plant proteins for muscle protein synthesis and identifies practical strategies to help optimize plant-based diets for muscle mass maintenance and growth.
Limits
As a narrative review, it lacks systematic search methodology and quantitative meta-analytic pooling. The abstract notes that very few studies have directly measured postprandial muscle protein synthesis following plant protein ingestion, existing literature is predominantly restricted to soy and wheat, and the actual efficacy of the proposed compensatory strategies on muscle protein synthesis remains untested.
Cited by
- supports The branched-chain amino acids valine, isoleucine, and leucine are found in greater abundance in animal protein than in plant protein.