[katyseagull]

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Fortunately, your body has mechanisms to reduce the output of OH radical and instead put out the less harmful nitric oxide. Still, though, it seems like for antioxidants to have any effect, they'd have to be at a comparable concentration to other things in your cells that these free radicals might react with.

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Thanks for your thoughts, Wookie. My concern is that the scientists have a very crude understanding of how the body works and how it utilizes various forms of nutrients. The article I linked tries to point out that just because something works in a test tube does not mean it will automatically work in the body. That's what they've discovered with antioxidant supplements. In fact, some studies indicate that it is not helpful and is possible harmful.

In 1992, researchers were studying lung cancer and found that the antioxidant beta carotene showed promise against cancer. They recruited 18,000 for a controlled study.


" the researchers pulled the plug two-thirds of the way through after discovering, to their surprise and horror, that those taking supplements were faring worse than the controls."

Also in the 1990s, researchers found that a diet high in vitamin E significantly reduced the incidence of heart disease. However, experiments using vitamin E supplements have been very disappointing. Several of the studies showed no effect and one showed that it caused harm.


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In fact, despite good evidence that vitamin E is a powerful antioxidant in the test tube, there is now serious doubt that it acts the same way in the body. "Vitamin E is not an antioxidant. In fact it must be protected against oxidation," says Angelo Azzi, a biochemist at Tufts University in Boston, Massachusetts. He points out that vitamin E exists in eight different forms in nature, all of which function as antioxidants in the test tube. Yet the body only uses one form, alpha tocopherol, which is pulled out of the bloodstream by a highly specialised protein in the liver. All the other forms are excreted. Azzi argues that evolution is unlikely to have gone to such great lengths simply to obtain an antioxidant from the diet. "There are millions of antioxidants," he says.

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The conclusion is becoming clear: whatever is behind the health benefits of a diet rich in fruits and vegetables, you cannot reproduce it by taking purified extracts or vitamin supplements. "Just because a food with a certain compound in it is beneficial, it does not mean a nutraceutical [with the same compound in] is,"

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I'm still very curious how they came up with the daily requirements for vitamins. Anyone know? I read one article that said it was based on very old data having to do with scurvy. I've no idea if that's true or not.