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Old 01-22-2008, 06:21 PM
Iggy Dalrymple's Avatar
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Default Vitamin C may hamper adaptation to exercise

Vitamin C may hamper adaptation to exercise

Taking vitamin C can blunt the body's response to endurance training, a new study in humans and rats shows.

Based on the findings, "the common practice of taking vitamin C supplements during training (for both health-related and performance-related physical fitness) should be seriously questioned," declared principal investigator Dr. Jose Vina of the University of Valencia in Spain and colleagues.

Exercisers take the antioxidant based on the assumption that it protects their muscles from the oxidative stress that results from physical exertion, Vina's group reports in the American Journal of Clinical Nutrition. However, the researchers point out, oxidative stress during exercise may actually help the body to build endurance by forcing muscles to adapt.

To investigate, Vina and his team had 14 sedentary men undergo 8 weeks of training, during which 5 of them took 1 gram of vitamin C daily. They also put 24 rats through 3- and 6-week exercise training protocols, and gave half of the animals vitamin C daily. The men who didn't take vitamin C showed a 22 percent increase in their body's ability to take up and use oxygen during exercise, compared with just a 10.8 percent increase for the men given vitamin C. Similar results were seen for the rats.
Dr. Cinque's comments: I have to admit I am very surprised by this. Why should taking one thousand milligrams of Vitamin C hamper athletic performance? Millions of athletes, the world over, take vitamins, including Vitamin C- especially Vitamin C- and yet, there are also many that don't. Doesn't it seem that if such a marked inhibitory effect on athletic performance occurred because of Vitamin C that it would have been previously noticed, or at least suspected, by coaches, trainers, and athletes themselves? I really don't know what to make of this. I can't point to any flaws in the study, and I'm not shouting conspiracy. But, suffice it to say, there are still a lot of unanswered questions. Yet, I don't say that their hypothesis is implausible. And the consideration of it reinforces my conviction that we must always be vigilant to look for "unintended consequences" any time we consider a health intervention, including nutritional interventions. However, even if this finding is further substantiated, it does not rule out every application of Vitamin C. For instance, the life-prolonging effect of high-dose Vitamin C in advanced cancer patients, which was demonstrated by Linus Pauling and confirmed by others, still stands, and I think it would be foolish to dismiss those results just because of these results. After all, one's priorities are quite different when advanced cancer is on the line. However, I don't deny that this report does give pause to the idea of taking mega-dose Vitamin C all the time- as a lifestyle- as per Linus Pauling. I only take a few hundred milligrams a day of Vitamin C in supplement form, and I have always been hesitant to take more. But, I'm sure there will be many retorts to this report. Some will argue that if Vitamin C had been given in conjunction with other antioxidants and vitamins, such as Vitamin E, lipoic acid, pantothenic acid, etc. that the results would have been much different. But that would be speculation too. One thing I keep reminding myself is that it's rarely a bad idea to err on the side of caution, and in this case, erring on the side of caution means taking less and not more.
I bet Dr Wombat would argue with this study.
For now we see through a glass, darkly.... 1st Corinthians 13:12
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