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Soy reduces harmful free radical formation during exercise better than whey protein
November 10, 2005 03:40 PM EST | Diet & Nutrition , Exercise , Women's Health | Email to Friend | Comments (0)
By Dr. Aaron Tabor, MD
Medical Research Director at www.revivalsoy.com
Evidence from recent clinical trials suggests that soy may have added exercise benefits compared to other protein sources, in particular whey protein (a popular protein among many athletes). Researchers from Ohio State University have just completed a study examining the effect of soy protein on muscle weight gain and “antioxidant status”.(1) A higher antioxidant status means that your body is able to better neutralize free radicals. Free radicals produced during exercise are harmful to muscle and other tissues.
In the study, men taking part in a weight training class were given protein bars containing either soy protein or whey protein (33 grams/day) for 9 weeks. The men consuming soy protein maintained a healthy antioxidant status, while the antioxidant status of men consuming whey protein actually worsened. By reducing free radical production during exercise, soy protein may help lessen muscle damage and fatigue. Both protein sources increased muscle mass of the men.
Another recent study tested the effects of soy protein and whey protein on “lipid peroxides” (higher levels are considered worse), in men performing moderate intensity, weight resistance exercise.(2) This study also compared soy to whey protein (men consumed 40 grams/day for 4 weeks prior to each exercise session). Lipid peroxide levels were reduced in the soy protein group as early as 5 minutes after the exercise session, while peroxide levels were not reduced until 24 hours after exercise in the whey protein group.
In summary, these new studies demonstrate that soy protein can help build muscle mass similar to more commonly used protein sources. However, soy protein provides the added benefit of reducing oxidative stress through the antioxidants naturally present in soy (isoflavones and saponins). Numerous studies indicate that soy isoflavones may be responsible for soy’s antioxidant properties.(3) Isoflavones are not found in whey protein or other common protein sources.
Medical References:
1. . Brown EC, DiSilvestro RA, Babaknia A, Devor ST. Soy versus whey protein bars: effects on exercise training impact on lean body mass and antioxidant status. Nutrition Journal 2004; 3:22-26.
2. Hill S, Box W, DiSilvestro RA. Moderate intensity resistance exercise, plus or minus soy intake: effects on serum lipids peroxides in young adult males. International Journal of Sport Nutrition and Exercise Metabolism 2004; 14:125-132.
3. Cancer Lett 2001 Oct 22;172(1):1-6. Effect of soy isoflavone supplementation on markers of oxidative stress in men and women. Djuric Z, et al. Barbara Ann Karmanos Cancer Institute, MI.
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