Vitamin C, Block E, promote the formation of free radicals, insulin sensitivity, researchers say

Exercise improves insulin sensitivity and prevent diabetes, but with additional antioxidants such as vitamins C and E effectively blunt this advantage, researchers report. 


Exercise helps increase the body's sensitivity to insulin in reactive oxygen species, or "free radicals" who are against antioxidants. These free radicals are damaging the cells and accelerate the aging process, but they are also used by the body to prevent cell damage after exercise, researchers say. 


"When you exercise you increase your sensitivity to insulin, and if you are at risk for diabetes, improving insulin sensitivity is good," said researcher Dr. Ronald S. Kahn, Mary K. Iacocca Professor of Joslin Diabetes Center and Harvard Medical School. 


One of the reasons that exercise improves insulin sensitivity is a cause of oxidative stress on the muscles. Muscles are responsible for this deficiency by creating free radicals, "said Kahn. 




"If you take antioxidants like vitamins C and E, you are blocking oxidative stress reactions, but we must also block the beneficial effects of exercise on insulin sensitivity," he said. 


This report is published in the online edition this week, Proceedings of the National Academy of Sciences. 


To investigate, the team examined the benefits of exercise Kahn on insulin resistance increases by 39 young people, about half of them take extra vitamins C and E. 


Kang team found that men taking vitamin supplements did not change in their insulin resistance, but men do not take vitamins were increased free radicals, which increases insulin resistance. One month after withdrawal of vitamin sensitivity to insulin was restored, the researchers noted. 


"If you're exercising, in particular, to reduce the risk of developing diabetes, you should not take vitamin C and E, because you will block some of the beneficial effect of physical exercise to prevent diabetes," said Kahn.