Study Says Soy Protein Ineffective for Muscle Growth

Need another reason to choose whey protein over soy when trying to preserve and build lean muscle mass? A new study from McMaster University in Canada found that when compared to whey protein, ingesting soy protein after a workout or at rest does about as much as plain water for muscle protein synthesis.

The study randomized thirty elderly men into three treatment groups to test the effects of ingesting 0 grams of protein, 20 grams of soy protein, or 40 grams of soy protein at rest and after a bout of resistance exercise. These effects were then compared to previous responses in similar aged men who had ingested 20 grams or 40 grams of whey protein at rest and after resistance exercise.

Results showed that rates of muscle protein synthesis for ingesting 20 grams of soy protein were no different than ingesting 0 grams of protein. The higher dose of soy protein, 40 grams, only modestly increased rates of muscle protein synthesis after exercise in comparison to people who consumed no protein.

In contrast, previous data from the study authors showed that consuming whey protein at rest and after exercise has shown to induce muscle protein synthesis whether in a dose of 20 or 40 grams, with the larger dose having a greater effect.

“We report that soy protein isolate is relatively ineffective in its capacity to stimulate MPS [muscle protein synthesis] in the elderly when compared to whey protein,” wrote the researchers.

The findings from this study should speak to aging adults who are looking to avoid the muscle-wasting effects of sarcopenia, as protein source and dose are showing more and more to be critical in avoiding age-related muscle loss.

Read more: Isagenix Health

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