Resveratrol is a substance found in grapes and other plants. Many of the supplements on the market extract it from the Japanese knotweed plant, which is a plentiful and inexpensive source. Switzerland's Royal DSM NV sells a synthetic version called resVida, which is found in supplements, a nonalcoholic fruit-flavored beverage and the new Winetime chocolate-fruit bar.

    Resveratrol has found been found in animal studies to prevent or slow progression of illnesses from cancer to cardiovascular disease-and even to extend the life span of some organisms. Since 2008, at least five human studies have been presented at scientific meetings showing human benefits, ranging from improved blood flow to the heart to better control of diabetes.

    The newest results are exciting, but some scientists say it is too early for the public to begin taking supplements, which contain as much resveratrol in one pill as dozens or hundreds of bottles of wine, depending on the dose. The proper dose for humans isn't yet known-and more isn't necessarily better.

    While some safety studies have been conducted on humans, it is too early to know if there are long-term side effects of high doses, says S. Jay Olshansky, a professor of epidemiology at the University of Illinois at Chicago. "I cannot emphasize enough: Do not experiment on your own body," he says.

    No one knows exactly how resveratrol works, but scientists believe it activates a wide range of genes, creating a cascade-like effect on a variety of body functions. Human data include a 100-person placebo-controlled study by Sirtris Pharmaceuticals Inc. that found lowered blood-glucose levels in diabetics who took the GlaxoSmithKline unit's proprietary formulation, SRT501, not yet on the market.

    A 19-person study presented earlier this month at a British scientific conference, sponsored by Royal DSM, found that "flow mediated dilation," a measure of cardiovascular health, increased an hour after taking resVida. At an American College of Sports Medicine conference last year, Dr. Maroon and colleagues reported that a three-month study of 51 people found a resveratrol-containing supplement not currently on the market increased endurance on a stationary bicycle compared with a placebo, and also increased verbal memory scores on a standardized test.

    Resveratrol是一種在葡萄及其它植物中發現的一種物質。市場上很多補品是從日本紫菀科植物提取出來的，這些植物數量多但不是很貴。瑞士的皇家DSM NV出售被稱作resVida合成的產品，在補品中發現了它，一款不含酒精的水果味的飲料及新的Winetime巧克力水果棒。

    Resveratrol 在動物研究中被發現，用于阻止或降低從腫瘤到心臟血管疾病的發展，甚至用于延長一些生物體的生命。自從2008年以來，至少有5例人類的研究在科學會議上提出展示人類的益處，改善到心臟的血流以更好地控制糖尿病。

    最新的結果是令人興奮地，但一些科學家說，對于公眾來說開始攝入這種補品尚早，依據劑量的不同，這種補品一丸中含有大量的resveratrol或是相當于成百瓶的葡萄酒。對于人類的合適的計量還是未知，而且并不是越多越好。

    雖然已從事人類的安全方面的研究，但現在還不能確定是否大劑量會對人體造成長期的副作用。S. Jay Olshansky,說，芝加哥的伊利諾斯州大學的流行病學教授。"我要強調的是：不要在自己的身體上做實驗。"

    沒有人知道resveratrol 怎樣起作用，但科學家相信它使大范圍的基因充滿活力，對于不同的身體功能產生影響。人類數據包括由Sirtris Pharmaceuticals Inc.進行的100人的安慰劑控制的研究發現，糖尿病患者在攝入了SRT501（還未上市）后血糖水平降低。

    本月早些時候，在英國科學大會上，由皇家DSM發起的一個19人參加的研究發現流動緩解膨脹，心臟血管健康的措施，在攝入resVida后一小時增強。在去年美國大學體育藥物大會上，Maroon博士和他的同事報告了51人為其三個月的研究發現含有resveratrol的目前還未上市的補品與安慰劑相比可以增加在固定自行車上的耐力，也可增加標準測試上的大腦記憶力分數