Resveratrol is a component of Ko-jo-kon, an oriental medicine used to treat diseases of the blood vessels, heart and liver. It came to scientific attention during the mid-90s as a possible explanation for the “French Paradox” — the low incidence of heart disease among the French people, who eat a relatively high-fat diet. Since then, it has been touted by manufacturers and examined by scientific researchers as an antioxidant, anti-cancer agent and phytoestrogen. It has also been advertised online as “the French paradox in a bottle.”
If you do a literature search and look at well-accepted peer review journals, there is very little published to support any of these effects of resveratrol. New work produced by both Amgen and Pfizer has cast doubt on the manner in which the health supplement is said to work. Prominent researchers supposed that it worked by activating a certain gene, SIRT1. This activation is thought to produce the benefits of a caloric restriction diet even among those with high fat and high caloric intake.
In 2009, in Chemical Biology and Drug Design, Amgen scientists published experimental results that indicate resveratrol does not, in fact, activate SIRT1. Pfizer scientists, in the Journal of Biological Chemistry in 2010, offered similar results, showing that resveratrol (and related substances such as SRT1720) do not active SIRT1 and did not reduce blood sugar in mice fed a high-fat diet. Thus, it suggests that resveratrol doesn’t work at all (though it’s not possible to translate mice studies into human studies). Despite what is promoted on many national television shows on health, none of the claims has been demonstrated in any valid human study.
While present in other plants, such as eucalyptus, spruce and lily, and in other foods such as mulberries and peanuts, resveratrol’s most abundant natural sources are vitis vinifera, labrusca and muscadine grapes, which are used to make wines. It occurs in the vines, roots, seeds,and stalks, but its highest concentration is in the skin. The resveratrol content of wine is related to the length of time the grape skins are present during the fermentation process. Thus, the concentration is significantly higher in red wine than in white wine, because the skins are removed earlier during white-wine production, lessening the amount that is extracted. Grape juice, which is not a fermented beverage, is not a significant source of resveratrol. Since wine is the most notable dietary source, it is the object of much speculation and research.
Resveratrol is also available from supplement pills and liquids, in which it is sometimes combined with vitamins and/or other ingredients. It is also an ingredient in topical skin creams. The supplements are generally labeled as containing from 20 to 500 mg per tablet or capsule. However, the purity of these products is unknown. And, because dietary supplements are loosely regulated, it should not be assumed that the labeled dosage is accurate.
Stay tuned for part 2 where we will talk more about resveratrol and the presumed anti-cancer, anti-aging and positive effects on the cardiovascular system.
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