Aim:
The aim of this study was to determine if there are gender differences in exercise-induced oxidative stress and in response to antioxidant treatment.
Methods:
In this double-blind, placebo-controlled study, 48 aerobically trained young men and women (aged 18-39 with an average age of 23) were randomly divided into 3 groups. For 2 weeks, Group 1 took an antioxidant supplement consisting of 1,000 mg vitamin C plus 400 IU vitamin E, Group 2 took a concentrate of powdered fruit, vegetable, and berry juice (FVB; Juice Plus+®), and Group 3 took placebo capsules. All participants were instructed to maintain their normal diet throughout the study.
Blood samples were analyzed for levels of antioxidants (e.g. reduced glutathione, total glutathione, and plasma vitamin E) and byproducts of oxidation (e.g. protein carbonyls, oxidized glutathione, and malondialdehyde). These analyses were performed before and after 2 sessions of vigorous exercise at 80% VO2 max for 30 minutes — the first at baseline and the second after 2 weeks of supplementation.
Results:
Before exercise, women had higher blood levels of antioxidants than men. After exercise, all 3 byproducts of oxidation increased in men and women, indicating higher levels of oxidative stress. Both the vitamin supplement and the FVB concentrate attenuated the post-exercise decrease in reduced glutathione and the post-exercise increase in oxidized glutathione and protein carbonyls compared to placebo, indicating a reduction in oxidative stress. This outcome held true for both genders. Additionally, both supplements eliminated the difference between vitamin E levels among the genders and raised vitamin C levels.
Conclusion:
Despite slightly different antioxidant protection prior to supplementation, men and women given similar antioxidant treatment for 2 weeks can enhance their antioxidant status at rest and show similar benefits to help reduce exercise-induced oxidative stress.
PubMed link: