Isoflavones restore altered redox homeostasis of antioxidant enzymes in healthy young men undergoing 80% peak oxygen consumption (VO2pk) exercise

Chen, Chung-Yen; Bakhiet, Raga M; Hart, Vanessa; Holtzman, Golde

doi:10.1016/j.nutres.2004.02.001

« Previous Next »Nutrition Research
Volume 24, Issue 5 , Pages 347-359, May 2004

Isoflavones restore altered redox homeostasis of antioxidant enzymes in healthy young men undergoing 80% peak oxygen consumption (VO₂pk) exercise

Chung-Yen Chen
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0430, USA
- Corresponding author. Current address: Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA. Tel.: (617) 556-3116; fax: (617) 556-3344.
Raga M Bakhiet
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0430, USA
Vanessa Hart
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0430, USA
Golde Holtzman
- Department of Statistics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0430, USA

Received 17 June 2003; received in revised form 17 November 2003; accepted 9 February 2004.

Abstract

Isoflavones have potential health effects attributed to their antioxidant activity. The objective of this study was to test whether isoflavones affected the enzymatic antioxidant defense system in young men undergoing 80% peak oxygen consumption (VO₂pk) exercise on cycle ergometer for 30 minutes. Fifteen pairs of subjects were randomly assigned to receive either high-genistein isoflavone extract (HGI, 150 mg/day) or placebo. Subjects engaged in two 30-minute sessions of exercise before and after 4 weeks of supplementation. There was a significant increase in plasma genistein and daidzein concentrations (499 and 415 ng/mL, P < 0.0001) after the supplementation, demonstrating isoflavone bioavailability. Isoflavones significantly increased pre-exercise erythrocyte superoxide dismutase (SOD) activity (P < 0.001). Furthermore, isoflavones prevented the exercise-induced decrease in activities of glutathione peroxidase (GPx) and catalase (CAT) and the increase in antioxidant enzyme (AE) ratio, maintaining all at pre-exercise levels. Our results suggest that isoflavones can restore the altered redox homeostasis of antioxidant enzymes due to exercise.

Keywords: Catalase, Exercise, Glutathione peroxidase, Humans, Isoflavones, Superoxide dismutase