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robdotcalm
May 18, 2009, 2:48 AM
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Another article showing the failure of nutritional supplements to be beneficial.
Vitamins E and C Found to Curb Exercise Benefits - NYTimes
http://www.nytimes.com/...8hlth&emc=hltha2
Cheers,
Rob.calm
(This post was edited by robdotcalm on May 18, 2009, 1:33 PM)
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bill413
May 18, 2009, 12:19 PM
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Interesting. I can see two possible conclusions from the article. One is their recommendation to not consume supplemental antioxidants. The alternative one is going back to Pauling's idea of massive doses of Vitamin C, to have more available than even the body would naturally produce. Note - I believe the latter is something that has been discredited.
I'm curious about the other studies on this, and on the journals in which they've appeared.
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czo
May 18, 2009, 1:11 PM
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Interesting you should post this here, as I was just reading a book on the effects of high doses of vitamins on exercise. (Little side-note: the article says Vitamins C and E. As far as I can tell, Vitamin A itself is not an antioxidant; only its precursor beta-carotene is.)
In reply to: One study noted that when a 500-milligram dose of vitamin C was provided shortly (4 hours) before testing, there was a significant improvement in strength and a significant reduction in maximal oxygen consumption, but no impact on muscular endurance. ¹ When subjects were provided with the same amount for 7 days, the result was an improvement in strength but a decrease in endurance. When the same subjects were provided with 2,000 milligrams each day for 7 days, the athletes' VO2 max was lowered, but no change was evident in endurance performance.
¹ Hickson, J.F., and Wolinsky, I., eds. 1989. Nutrition in exercise and sport. Boca Raton, FL: CRC Press, 121.
Unfortunately, I have neither access to the text referred nor the actual study, so I can't make a claim either way really.
There are a few other studies I have just run across, one of which claiming "Vitamin E Improves the Free Radical Defense System Potential and Insulin Sensitivity of Rats Fed High Fructose Diets", which appears to be just the opposite result. So it seems like there could be many additional factors that affect such a study, making any conclusion drawn suspect.
For me, it's just one more reason to eat well and avoid multi-vitamins.
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robdotcalm
May 18, 2009, 1:32 PM
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czo: you're right, it's vit E not vit A. I'll rename the post.
r.c
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jt512
May 18, 2009, 2:52 PM
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bill413 wrote: Interesting. I can see two possible conclusions from the article. One is their recommendation to not consume supplemental antioxidants. The alternative one is going back to Pauling's idea of massive doses of Vitamin C, to have more available than even the body would naturally produce. Note - I believe the latter is something that has been discredited. I'm curious about the other studies on this, and on the journals in which they've appeared.
Pauling's vitamin C hypothesis has been about as thoroughly discredited as anything in nutrition can be.
Jay
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jt512
May 18, 2009, 2:56 PM
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czo wrote: Interesting you should post this here, as I was just reading a book on the effects of high doses of vitamins on exercise. (Little side-note: the article says Vitamins C and E. As far as I can tell, Vitamin A itself is not an antioxidant; only its precursor beta-carotene is.) In reply to: One study noted that when a 500-milligram dose of vitamin C was provided shortly (4 hours) before testing, there was a significant improvement in strength and a significant reduction in maximal oxygen consumption, but no impact on muscular endurance. ¹ When subjects were provided with the same amount for 7 days, the result was an improvement in strength but a decrease in endurance. When the same subjects were provided with 2,000 milligrams each day for 7 days, the athletes' VO2 max was lowered, but no change was evident in endurance performance. ¹ Hickson, J.F., and Wolinsky, I., eds. 1989. Nutrition in exercise and sport. Boca Raton, FL: CRC Press, 121. Unfortunately, I have neither access to the text referred nor the actual study, so I can't make a claim either way really. There are a few other studies I have just run across, one of which claiming " Vitamin E Improves the Free Radical Defense System Potential and Insulin Sensitivity of Rats Fed High Fructose Diets", which appears to be just the opposite result. So it seems like there could be many additional factors that affect such a study, making any conclusion drawn suspect.
Especially if you are a rat on a high-fructose diet.
In reply to: For me, it's just one more reason to eat well and avoid multi-vitamins.
That is clearly the wrong conclusion. Epidemiology has consistently shown health benefits from daily multi-vitamin use. What you should avoid are mega-doses of isolated vitamins.
Jay
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jt512
May 18, 2009, 3:13 PM
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The article's characterization of the doses of the vitamins in the study as "moderate" is misleading. The doses are, in fact, quite large: 16 times the RDI for vitamin C, and 13 times the RDI for vitamin E. The evidence that mega-doses of vitamins do more harm than good continues to mount.
Jay
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bill413
May 18, 2009, 4:40 PM
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jt512 wrote: The article's characterization of the doses of the vitamins in the study as "moderate" is misleading. The doses are, in fact, quite large: 16 times the RDI for vitamin C, and 13 times the RDI for vitamin E. The evidence that mega-doses of vitamins do more harm than good continues to mount.
Do you think the harm of megadoses is a question of balance or of excess?
Bill
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altelis
May 18, 2009, 7:15 PM
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bill413 wrote: jt512 wrote: The article's characterization of the doses of the vitamins in the study as "moderate" is misleading. The doses are, in fact, quite large: 16 times the RDI for vitamin C, and 13 times the RDI for vitamin E. The evidence that mega-doses of vitamins do more harm than good continues to mount. Jay, Do you think the harm of megadoses is a question of balance or of excess? Bill
And to add to that question:
Is there a difference b/w mega-dosing of fat and water soluble vits?
Any correlation w/ water soluble vit mega-doses and kidney probs?
yea yea, i could do a search, but i've got my own research deadline looming and would rather waste my time here than on pubmed 
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jt512
May 18, 2009, 7:51 PM
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bill413 wrote: jt512 wrote: The article's characterization of the doses of the vitamins in the study as "moderate" is misleading. The doses are, in fact, quite large: 16 times the RDI for vitamin C, and 13 times the RDI for vitamin E. The evidence that mega-doses of vitamins do more harm than good continues to mount. Jay, Do you think the harm of megadoses is a question of balance or of excess? Bill
I would think that it's more a consequence of quantity; after all, what would you take to "balance" antioxidants? Oxidants?
Jay
(This post was edited by jt512 on May 20, 2009, 6:45 AM)
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jt512
May 18, 2009, 7:59 PM
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altelis wrote: bill413 wrote: jt512 wrote: The article's characterization of the doses of the vitamins in the study as "moderate" is misleading. The doses are, in fact, quite large: 16 times the RDI for vitamin C, and 13 times the RDI for vitamin E. The evidence that mega-doses of vitamins do more harm than good continues to mount. Jay, Do you think the harm of megadoses is a question of balance or of excess? Bill And to add to that question: Is there a difference b/w mega-dosing of fat and water soluble vits?
Well, yeah. Excess intake of fat-soluble vitamins can be flat-out toxic. Harmful effects of excess water-soluble vitamins, to the extent that such harm exists, would be subtler, and little is known about them or their mechanism. However, three major beta-carotene trials showed harm, and there is at least theoretical reason to suspect that vitamin C and other antioxidants could actually be pro-oxidative in excess.
In reply to: Any correlation w/ water soluble vit mega-doses and kidney probs?
I don't know.
Jay
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