Wednesday, November 11, 2009

The problem with resveratrol

We continue to hear a lot about resveratrol these days. If you follow news releases on wine and health topics (which I do so you don’t have to) it seems that all of the goodness of wine can be attributed to this miracle molecule from wine grape skins. It is a pretty compelling story when you look at all of the basic science research on the subject, which offers tantalizing prospects of a cure for Alzheimer’s disease, cancer, heart disease, diabetes, even the common cold (see below). But there’s a problem.

To begin with, scientists first looked to wine-derived compounds because of all of the data showing a correlation between moderate drinking and lowered chances of having any of the above-mentioned diseases. When researchers discovered that resveratrol activates enzymes called sirtuins that extend lifespan in certain organisms, the door to a whole new area of scientific inquiry was opened. What resveratrol does in a Petri dish seemed to explain the benefits of drinking wine, and so now dozens of manufacturers are offering resveratrol supplements as a way to get wine’s goodness without the alcohol. So what’s the problem?

The thing is, there isn’t enough resveratrol in wine to explain why wine drinkers are so much healthier and live longer than teetotalers on average. It has been calculated that some 200 bottles would be required to get the daily dose required to cause the same effect in people as it does in lab rats. And, as we have pointed out here before, resveratrol isn’t very well absorbed after oral ingestion anyway. So clearly there must be something else going on. Several papers do offer a possible explanation: when resveratrol is given in combination with other wine polyphenols, the effects are often multiplied. And alcohol in the right amounts has specific heart-health benefits too.

A similar thing happened with vitamins. Their discovery a hundred years ago was the biggest advance in nutritional science of the 20th century, as I believe polyphenol science will be for the 21st. But when vitamins were extracted out their natural sources (usually fruits and vegetables) and given as supplements, no benefits in terms of age-related diseases were found. That bears repeating: No benefits to taking antioxidant vitamins, period. The same may turn out to be true for wine. So just eat your vegetables and drink your wine.

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