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Old 05-13-2009, 12:35 PM   #9
Stuart Buck
Member Stuart Buck is offline
 
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Join Date: Apr 2008
Location: Springdale  AR
Posts: 260
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, Viņa 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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