Athletes who participate in "extreme" exercise such as marathon running may benefit from taking daily antioxidant supplements, finds a new study.
The study, published in the European Journal of Physiology, suggest that taking antioxidants, such as a mixture of vitamins C and E and beta-carotene, provides extra protection during strenuous exercise, and that maintaining adequate levels of antioxidants could decrease the risk of infection.
Antioxidants are necessary to prevent the damage done by free radicals, the molecules that can damage different tissues and organs, including the immune system, and lead to the development of several chronic diseases, including diabetes, heart disease and cancer.
Former studies have shown that vigorous exercise reduces the ability of antioxidants to protect the immune system.
The authors noted that other studies have shown that taking nutritional antioxidant supplements reduce the risk of developing upper respiratory infections after prolonged exercise, such as running a marathon.
In this 90-day study, twenty regular runners or cyclists received either a placebo or 500 IU of vitamin E plus 30 mg of beta-carotene daily. During the last 15 days of the trial, those taking the antioxidants also received 1,000 mg per day of vitamin C.
The participants continued to train on average 14 hours per week. Vitamin levels and several markers for determining antioxidant activity were taken before and at the conclusion of the study.
Results showed that the athletes with a daily intake of antioxidants had a significant increase in blood levels of vitamins E and C and beta-carotene, while no change was seen in the group taking a placebo. In addition, at the end of the study the activity of certain enzymes that maintain antioxidant balance in the body were significantly higher in the antioxidant group than in the control group.
Dietary intake was unknown, however, and while this could have an effect on blood levels of antioxidants, it is generally accepted that the amounts of vitamins E and C investigated in the study require supplementation as it would be almost impossible to obtain those amounts through diet alone.