Antioxidant Vitamins Reduce The Effect of Exercise

By Margarita Nahapetyan

Taking antioxidant vitamins C and E may reduce some of the most important beneficial effects of exercise, says a new study by German scientists, who found that taking these vitamins after a workout appears to prevent physical exercise from improving the body's energy regulation.

Dr. Michael Ristow, of the University of Jena, and his colleagues have shown that antioxidant supplements like vitamin C or E can interfere with the benefits of exercising. Also, according to some previous studies, taking antioxidants may expedite lethal outcome through an unknown mechanism. The experts say that one possible reason of such negative reaction could be that the free radicals might be used by the body in order to prevent cellular damage after exercise.

To come up with this conclusion, Dr. Ristow and his team recruited 40 volunteers with the ages between 25 and 27 years. Twenty participants were previously trained and another twenty were previously untrained. The participants were randomly assigned into two groups - half were asked to take 1000 milligrams of C vitamin and 400 IU of E vitamin on a daily basis, which is an equivalent to the amounts in some vitamin supplements. The participants were also asked to workout for 85 minutes every day, 5 days a week, for a period of one month. The investigators examined insulin sensitivity in all young men before and after 4 weeks of workout.

The investigators found that those volunteers who took vitamin C and E supplements showed no improvement in insulin sensitivity as well as in changes of their free radical levels, while those participants who did not take these antioxidant vitamins showed increased levels of free radical oxidative stress. After a month of intensive exercise training, insulin sensitivity was restored only in the group of men who did not take vitamin supplements. Participants who took the vitamin supplements fared worse, metabolically. Previous training had no effect, according to the researchers.

Previous research has shown the evidence according to which antioxidants protect cells against the damage caused by free radicals, therefore putting off the process of aging and diminishing the risk of certain diseases such as cancer, for example. German scientists, in turn, found that these free radicals are good for people as they protect the body against diabetes by increasing sensitivity to insulin. In the conclusion the investigators said that free radicals are hazardous in excess or if allowed to persist for a long period of time. But short term doses of these compounds act like a vaccine, they said, helping the body to increase its defenses against chronic stressors.

The study is published online May 11 in the Proceedings of the National Academy of Sciences journal.