Why Antioxidant Supplements May Harm, Not Help

A new study from researchers at University of Bonn and Harvard gives a plausible explanation for the negative effects of antioxidant vitamins that have been reported in several previous studies. They show that people who take 1000 mg/day of vitami
C and 400 IU/day of vitami
E do not gain the benefits of increased insulin sensitivity when they exercise (Proceedings of the National Academy of Sciences, May 12, 2009). Here's a detailed explanation of this important finding:

* When blood sugar levels rise too high, sugar sticks on the surface of cell membranes and can never get off; it is converted in a series of chemical reactions to sorbitol that destroys cells.

* Contracting muscles help to prevent this damage by removing sugar so fast from the bloodstream that blood sugar levels do not rise too high.

* Food is converted to energy to power your muscles by a series of chemical reactions that shuffle electrons from molecule to molecule.

* This occurs primarily in the mitochondria, small energy- producing chambers in cells, that number anywhere from a few to thousands in each cell.

* As electrons are shuffled to produce energy, extra electrons can accumulate. They can either end on hydrogen atoms to form water and become harmless, or they can end up on oxygen atoms to form free radicals that can damage cells. This can cause cancers, heart attacks and other life-shortening conditions.

* Exercise speeds up the reactions that turn food into energy. So exercise increases the production of free radicals.

* The body responds to this increased production of free radicals during exercise by producing tremendous numbers of antioxidants that sop up the free radicals and render them harmless.

* Exercise prolongs life and prevents heart attacks and cancers by causing the body to dispose of free radicals by the increased production of antioxidants.

* This new study explains that if you exercise and take antioxidant vitamins C and E, you prevent your own body from making large amounts of antioxidants during exercise, so more free radicals (oxidants) accumulate in your body and more cells are damaged.

This study reinforces the recommendations I have given for years: Exercise every day, and get the antioxidant vitamins and other nutrients your body needs from foods, not from pills. Eat a wide variety of foods including large amounts of fruits, vegetables, whole grains, beams, nuts and other seeds.