Five published research studies on the red-wine molecule resveratrol in the last two months of 2006 led to front-page coverage in The New York Times and a marked increase of consumer interest in the supplement.

In separate, independent research at Harvard University and elsewhere around the world, researchers reported that resveratrol can extend life span and offset the bad effects of a high-fat diet, improve physical endurance and stamina, prevent damage to the heart during a heart attack, protect the brain from toxic chemical insult, and block prostate-cancer incidence.

"Public interest is dramatically up, but from near-zero," said Bill Sardi, president of resveratrol manufacturer Longevinex in Nevada. "In September 2006, the number of Yahoo! searches worldwide was 1,600, and in November it was 35,000. But put in perspective, there are 100,000 hits for hemorrhoids. Longevinex has a lot of new customers but the public has heard mixed messages."

Among the mixed messages, said Sardi, is that mainstream media portrayals of the research pointed not to resveratrol as much as to red wine — then said a person couldn't possibly drink enough wine to see any effect without increasing liver toxicity from the alcohol.

"Resveratrol will sell well when public misconceptions get cleared up," said Sardi. "For this ingredient that has so much research including from Harvard, MIT, the National Institutes of Aging ... I don't know who the public is waiting for to tell them. It should have moved millions with those headlines."

Resveratrol is found in the skin of grapes and in red wine — in particular pinot noir varieties — and is said to be responsible for the so-called French paradox — the French eat a more high-fat diet but have almost three times less heart disease than Americans. Its effects are said to come from its ability to mimic calorie restriction, activating the Sirtuin-1 gene that is turned on under normal circumstances only by a limited-calorie diet. The supplement ingredient is sourced from the Chinese giant knotweed plant at resveratrol-extract levels ranging from 10-95 per cent, and is often mixed in with grape powder (with low resveratrol levels) to fulfil label claims that the product is derived from red-wine grapes.

Another issue with resveratrol supplements is that the molecule degrades in the presence of heat or light. Sardi believes his exclusive arrangement with Capsugel, using its Licaps supplement system, takes care of that problem, and believes supplements that do not use such a system would be likely to degrade by the time the product is manufactured.