Antioxidants Considered Harmful

Dennis Mangan has recently blogged on a couple of studies (here and here) suggesting that antioxidant supplementation essentially nullifies many of the health benefits associated with exercise.

Any number of caveats apply—these are short-term studies, only a couple of antioxidants were considered, not all possible health effects were measured, the findings may or may not apply to antioxidant-rich foods, etc.—but I think there's enough in here to give those of us who do take antioxidant supplements some cause for concern.

Edit: The reason for this, as I understand it, is that free radicals play a critical role in the physiological changes caused by exercise. When antioxidants neutralize the free radicals, those physiological changes are never triggered.

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Large amounts?

I saw some articles about this months ago, came to some tentative conclusions about what wasn't made entirely clear, but would like to hear an independent assessment. My sense is that the "nullification" is associated with the extraordinarily large doses typical of vitamin pill poppers. It is not associated (or at least not known to be associated) with either drinking orange juice with your breakfast or taking a daily multivitamin that has merely 100% of your recommended daily allowance.

Sound right?

Maybe. The studies used one

Maybe. The studies used one gram of vitamin C and 400 IU of vitamin E. The latter is much more than you're likely to get from diet (a serving a food particularly rich in vitamin E might have 10-15 IU), but it's not at all difficult to get over half a gram of vitamin C per day from diet alone. Peaches, strawberries, bell peppers, and broccoli all provide 100+ mg of vitamin C per serving. But it's unclear whether vitamin-C-rich foods contain some other compound that mitigates the negative effects of isolated ascorbate.

Good to know

Good to know that my program is as good as that of someone who exercises and eats lots of fruit and veggies. :)

Very doubtful

I started "megadosing" (3 g/day) Vitamin C recently, but as I don't really exercise much I have no anecdotal evidence one way or another. However, I find it hard to believe that a substance that, if not for an accident of primate genetics millions of years ago, our bodies should be producing on their own in large quantities could be harmful in any significant way.

The first link states

Our paleolithic ancestors would probably have been ingesting only small amounts of vitamin C, so any dose larger than say, 100 mg, must be considered quite unnatural.

This ignores the fact that it could be considered "quite unnatural" for our only source of Vitamin C to be external inputs such as fruit. Not to mention the dubious nature of taking the diets of our ignorant ancestors as a guide for propriety.

However, I find it hard to

However, I find it hard to believe that a substance that, if not for an accident of primate genetics millions of years ago, our bodies should be producing on their own in large quantities could be harmful in any significant way.

Who's to say it was an accident? This is pure speculation on my part, but it's possible that vitamin C production was selected against for this very reason.

True, but it seems unlikely

True, but it seems unlikely given the prevalence of Vitamin C production in living organisms and the complexity of the chemical mechanism for producing it (most of which mechanism is still present in our bodies, I believe).