Vitamins C and E can slow down the improvement of muscular endurance by violation of adaptation of muscle cells to exercise, showed a study published February 3 in the journal of physiology (The Journal of Physiology). As supplements containing vitamins C and E, are widely used, understanding that they are breaking the cellular and physiological mechanisms of adaptation to exercise is beneficial for people exercising in order to be healthy, and athletes.
Dr. Goran Paulsen, who led the study at the Norwegian School of sports Sciences, explained:"Our results show that supplementation with vitamins C and E, reduce training induced increase of mitochondrial proteins, which are needed to improve muscular endurance". In 11-week study, 54 young, healthy men and women were randomly divided to receive either 1000 mg vitamin C and 235 mg of vitamin E (consistent with amounts found in pharmaceutical supplements) or a placebo pill, containing no active components. None of the subjects and researchers did not know which members gets the vitamins and who placebo. The participants completed an endurance training: three to four lessons a week, mainly running. Fitness tests, blood sampling and muscle biopsy were conducted before and after the intervention. Although the supplements did not affect maximal oxygen uptake or the results of the Shuttle run on 20 meters, the results showed that markers for the production of new muscle mitochondria — the power supply for cells — increased only in the group who do not use supplements. The national health service (The NHS) argues that consuming less than 540 mg of vitamin E and 1000 mg of vitamin C per day is unlikely to cause harm. Dr Paulsen says: "Our results show that high doses of vitamin C and E — which are commonly found in supplements — should be used with caution, especially if you are performing endurance exercise". Was discovered a significant trend, but the molecular processes requires further research. It is possible that high doses of vitamins C and E act as antioxidants and partially neutralize this oxidative stress and thus to block the development of muscular endurance.