Taking antioxidants, like vitamins C and E, is thought to prevent body tissue damage (also called oxidative stress) that’s been implicated in everything from cancer and heart disease, to the natural aging process. But according to Dr. Michael Ristow, a researcher at the University of Jena, vitamin use after exercise could actually undo some of the positive effects of the workout. Some of the damaging chemical by-products produced by the body when it sweats (known as free radicals) might actually have a positive effect by boosting the body’s sensitivity to insulin, which is lost in Type 2 diabetes. In the study, after four weeks of intensive exercise training, the men who took vitamin supplements were worse off metabolically, as their insulin sensitivity was impacted when compared to men who didn’t take vitamins. Consuming high doses of vitamins can have a negative health impact, Dr. Elisabeth Weichselbaum of the British Nutrition Foundation told the BBC. “If you stick to a healthy and varied diet, you generally get enough of the nutrients you need and you
don’t run the risk of consuming large amounts that may be harmful for you.”