Does soy protein speed up recovery?K
Soy Protein, Muscle Damage, and Recovery
The main purpose of taking a protein supplement is to provide your body with the nutrients it needs to recover from a workout. The recovery process is what makes us bigger, faster, and stronger. Any strategy which improves this process should lead to better performance and size gains.
Soy protein doesn’t have a great reputation in the performance world. Unfortunately, there is not a great deal of research specifically looking at soy protein to enhance recovery. However, there is some to suggest the isoflavones and saponins found in soy protein have anti-inflammatory and anti-oxidative properties, giving it great potential to enhance recovery1.
The Research on Soy Protein and Recovery
In a 2016 study, researchers tested how soy affected recovery in boxers and cyclists over a four week period. The 40 participants were broken up into two groups: one group supplemented with soy protein isolate, the other group was given a placebo (artificially sweetened beverage mixed with water). Participants performed a series of jumps; five sets of 20 drop jumps with 10 seconds of rest between jumps and 2 minutes of rest between sets. This protocol was chosen because of its ability to produce muscle damage1.
The soy protein group took about 20 grams of protein, twice daily. Researchers measured muscle damage, soreness, and recovery in a number of ways. The results were mixed. Soy protein enhanced recovery by reducing inflammation and muscle damage markers. This enhancement was only seen in the boxers. The results also showed that soy protein was able to decrease strength losses after the drop jump protocol. The soy group also saw less muscle soreness following exercise. The researchers concluded that soy protein “is effective in ameliorating the negative effects of exercise induced muscle damage.”1
The second study compared the effects of whey, casein, or soy on muscle protein synthesis. While this isn’t a direct measure of muscle damage, it can indicate a protein’s ability to help recovery. Muscle protein synthesis is another way of saying building muscle. Two of the biggest stimulators of protein synthesis are eating and exercise2.
This study used 18 men split into three groups: one whey, one casein, and one soy group. Subjects performed a strength training routine consisting of four sets of leg press and four sets of leg extensions. Subjects then consumed about 20 grams of their respective protein. Researchers took blood samples to measure protein synthesis rates. The results showed protein synthesis rates in the whey and soy groups were higher than the casein group2.
Does soy protein help with recovery?
The research on this topic shows that soy protein does have the ability to improve recovery. In the first study, soy helped with inflammation and other markers of muscle damage. It was also able to decrease soreness and preserve strength after an intense workout. The second study showed soy protein, when mixed with resistance training, was able to increase protein synthesis.
Soy protein is a staple for anyone looking to eliminate or drastically reduce consumption of animal products. Though it doesn’t have a great reputation in the exercise world, the research shows there is a clear benefit in using soy protein to enhance athletic performance.
Soy Protein Recommendations
The studies highlighted above used 20 grams of soy protein either once or twice daily, which should work for most. For the vast majority of the population, eating excessive amounts of protein does not lead to increased performance gains; 20-40 grams of protein supplements per day is sufficient.
Soy Protein Series
- Shenoy, S., Dhawan, M., & Sandhu, J. S. (2016). Four Weeks of Supplementation With Isolated Soy Protein Attenuates Exercise-Induced Muscle Damage and Enhances Muscle Recovery in Well Trained Athletes: A Randomized Trial. Asian Journal of Sports Medicine, 7(3). doi:10.5812/asjsm.33528
- Tang, J. E., Moore, D. R., Kujbida, G. W., Tarnopolsky, M. A., & Phillips, S. M. (2009). Ingestion of whey hydrolysate, casein, or soy protein isolate: Effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. Journal of Applied Physiology, 107(3), 987-992. doi:10.1152/japplphysiol.00076.2009