Study: Popular supplement quercetin does not enhance athletic p...(gnificance of the finding unclear. Publi...)

Date:9/3/2009

gnificance of the finding unclear. Published studies on competitive runners and cyclists have found no improvement in performance. A recent published study by the same researchers who reported mitochondrial and endurance increases in mice, however, found that volunteers who consumed a drink containing quercetin saw a 13 percent improvement in endurance. Cureton said the reason for the conflicting results is unknown, but added that several other studies currently in review for publication also have found no performance-enhancing effect.

Cureton and his colleagues hypothesized that the athletes used in the previous studies might not have benefitted from quercetin because they had already maximized their mitochondrial density through aerobic training. To address that possibility, the researchers recruited 30 men who were healthy but not endurance trained and randomly assigned them to either an experimental group or a placebo group.

The experimental group consumed a sports drink containing 250 milligrams of quercetin four times a day for up to 16 days, a dose and duration similar to previous human studies and comparable to studies in mice. The placebo group received the same sports drink without quercetin.

Because the mechanisms of quercetin's action are unclear, the researchers examined a number of variables in what is the most comprehensive study to date on its effect on athletic performance. The variables included:

• The rate at which muscles synthesize energy after strenuous exercise;
• Peak oxygen consumption;
• The rate of perceived exertion during cycling;
• Metabolic changes, such as the percentage of energy derived from fats and carbohydrates (more conditioned individuals tend to use more fat for energy);
• Performance on a cycling test; and
• Strength loss following prolonged cycling.

Cureton notes that had there been a performance-enhancing effect of quercetin, a sample si
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Contact: Sam Fahmy sfahmy@uga.edu 706-542-5361 University of Georgia Source:Eurekalert

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