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Old 05-12-2009, 08:10 AM   #1
Stuart Buck
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Don't Take Vitamins

So says a new study reported in the NY Times http://www.nytimes.com/2009/05/12/he...12exer.html?em {WFS}

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The researchers, led by Dr. Michael Ristow, a nutritionist at the University of Jena in Germany, tested this proposition by having young men exercise, giving half of them moderate doses of vitamins C and E and measuring sensitivity to insulin as well as indicators of the body’s natural defenses to oxidative damage.

The Jena team found that in the group taking the vitamins there was no improvement in insulin sensitivity and almost no activation of the body’s natural defense mechanism against oxidative damage.

The reason, they suggest, is that the reactive oxygen compounds, inevitable byproducts of exercise, are a natural trigger for both of these responses. The vitamins, by efficiently destroying the reactive oxygen, short-circuit the body’s natural response to exercise.

“If you exercise to promote health, you shouldn’t take large amounts of antioxidants,” Dr. Ristow said. A second message of the study, he said, “is that antioxidants in general cause certain effects that inhibit otherwise positive effects of exercise, dieting and other interventions.” The findings appear in this week’s issue of The Proceedings of the National Academy of Sciences.

The effect of vitamins on exercise and glucose metabolism “is really quite significant,” said Dr. C. Ronald Kahn of the Joslin Diabetes Center in Boston, a co-author of the report. “If people are trying to exercise, this is blocking the effects of insulin on the metabolic response.”

The advice does not apply to fruits and vegetables, Dr. Ristow said; even though they are high in antioxidants, the many other substances they contain presumably outweigh any negative effect.
Read the whole thing.
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Old 05-12-2009, 08:15 AM   #2
Rene Forestier
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Re: Don't Take Vitamins

This is just more evidence of the importance of real food...the vitamins are necessary for life, but only in the form of food...there are just too many interactions b/w food constituents that can't be reproduced by isolated vitamin supplements.
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Old 05-12-2009, 05:25 PM   #3
Jeremy Kauffman
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Re: Don't Take Vitamins

Here's the actual study (w/f safe).

The results of this are pretty shocking and there's no reason to believe that it has anything to do with the fact that the Vitamin C/E were administered via vitamins rather than foods.

Fortunately, at the dosages they administered, 1000% DV of vitamin C and 400 IU of vitamin E, you'd have to eat a rather large amount of peppers/oranges/etc. to match the vitamin C levels and an absurd amount of avacados/almonds/etc. to match the vitamin E levels.

Nonetheless, the results were significant and should give pause to any athlete that is currently taking multivitamin supplements with large amounts of antioxidants.
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Old 05-12-2009, 05:58 PM   #4
Matt Berardi
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Re: Don't Take Vitamins

Quote:
Originally Posted by Jeremy Kauffman View Post
Here's the actual study (w/f safe).

The results of this are pretty shocking and there's no reason to believe that it has anything to do with the fact that the Vitamin C/E were administered via vitamins rather than foods.

Fortunately, at the dosages they administered, 1000% DV of vitamin C and 400 IU of vitamin E, you'd have to eat a rather large amount of peppers/oranges/etc. to match the vitamin C levels and an absurd amount of avacados/almonds/etc. to match the vitamin E levels.

Nonetheless, the results were significant and should give pause to any athlete that is currently taking multivitamin supplements with large amounts of antioxidants.
yeah really, this study bothers me..... you think you are eating the healthiest foods in existence and a study goes and shows you that you might be shooting yourself in the feet! I take Orange Triad by Controlled Labs myself.

The thing I didn't see is whether it matters the time of day that you take the supplement
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Old 05-12-2009, 07:16 PM   #5
Rene Forestier
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Re: Don't Take Vitamins

Quote:
Originally Posted by Jeremy Kauffman View Post
Here's the actual study (w/f safe).

The results of this are pretty shocking and there's no reason to believe that it has anything to do with the fact that the Vitamin C/E were administered via vitamins rather than foods.

Fortunately, at the dosages they administered, 1000% DV of vitamin C and 400 IU of vitamin E, you'd have to eat a rather large amount of peppers/oranges/etc. to match the vitamin C levels and an absurd amount of avacados/almonds/etc. to match the vitamin E levels.

Nonetheless, the results were significant and should give pause to any athlete that is currently taking multivitamin supplements with large amounts of antioxidants.
That's exactly my point. We probably don't need vitamins in excess of what we can't reasonably obtain from nutrient-rich food.
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Old 05-12-2009, 07:43 PM   #6
Steven Low
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Re: Don't Take Vitamins

This is nothing new honestly.

There's several large studies which you can find in pubmed on VitC and VitE megadosing.... basically to no effect. Actually, with the VitC they found out there was actually a very slightly increase risk in developing cancer.

I'm surprised that the media is making it come to light now since I think a lot of these studies were done in the early or late '90s. The only thing "new" about this study is that it was done specifically for diabetes type II, and tested against exercise.
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Old 05-13-2009, 06:53 AM   #7
Stuart Buck
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Re: Don't Take Vitamins

I've seen earlier studies saying that antioxidants basically didn't help promote health, but isn't it new to have a finding that antioxidants are actually preventing the body from building up its own natural response to oxidative stress?

Anyway, this is yet another reason that I have to wonder whether what I believe now, or what I'm doing now, will turn out in 10 or 15 years to be worthless. I take fish oil and Vitamin D, for example, b/c there seems to be plenty of evidence that those two supplements are beneficial . . . but will that turn out to be wrong too?
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Old 05-13-2009, 07:31 AM   #8
Matt Berardi
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Re: Don't Take Vitamins

Quote:
Originally Posted by Steven Low View Post
This is nothing new honestly.

There's several large studies which you can find in pubmed on VitC and VitE megadosing.... basically to no effect. Actually, with the VitC they found out there was actually a very slightly increase risk in developing cancer.

I'm surprised that the media is making it come to light now since I think a lot of these studies were done in the early or late '90s. The only thing "new" about this study is that it was done specifically for diabetes type II, and tested against exercise.
So is megadosing the culprit or should all multivitamins be avoided?
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Old 05-13-2009, 12:35 PM   #9
Stuart Buck
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Re: Don't Take Vitamins

Just to add another study from last year recommending against Vitamin C:
Quote:
http://www.ncbi.nlm.nih.gov/pubmed/18175748 wfs

Am J Clin Nutr. 2008 Jan;87(1):142-9.Click here to read

Oral administration of vitamin C decreases muscle mitochondrial biogenesis and hampers training-induced adaptations in endurance performance.

Gomez-Cabrera MC, Domenech E, Romagnoli M, Arduini A, Borras C, Pallardo FV, Sastre J, Viña J.

Department of Physiology, Faculty of Medicine, University of Valencia, Valencia, Spain.

BACKGROUND: Exercise practitioners often take vitamin C supplements because intense muscular contractile activity can result in oxidative stress, as indicated by altered muscle and blood glutathione concentrations and increases in protein, DNA, and lipid peroxidation. There is, however, considerable debate regarding the beneficial health effects of vitamin C supplementation.

OBJECTIVE: This study was designed to study the effect of vitamin C on training efficiency in rats and in humans.

DESIGN: The human study was double-blind and randomized. Fourteen men (27-36 y old) were trained for 8 wk. Five of the men were supplemented daily with an oral dose of 1 g vitamin C. In the animal study, 24 male Wistar rats were exercised under 2 different protocols for 3 and 6 wk. Twelve of the rats were treated with a daily dose of vitamin C (0.24 mg/cm2 body surface area).

RESULTS: The administration of vitamin C significantly (P=0.014) hampered endurance capacity. The adverse effects of vitamin C may result from its capacity to reduce the exercise-induced expression of key transcription factors involved in mitochondrial biogenesis. These factors are peroxisome proliferator-activated receptor co-activator 1, nuclear respiratory factor 1, and mitochondrial transcription factor A. Vitamin C also prevented the exercise-induced expression of cytochrome C (a marker of mitochondrial content) and of the antioxidant enzymes superoxide dismutase and glutathione peroxidase.

CONCLUSION: Vitamin C supplementation decreases training efficiency because it prevents some cellular adaptations to exercise.
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