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Dear Dr. Vinny,

Some time ago I read that the addition of pectolytic enzymes during fermentation substantially increased the amount of resveratrol in the finished wine, without affecting the other qualities of the wine. It would seem to be a great marketing ploy, given the health benefits attributed to red wines. Why has no one considered it?

—Mike J., Charlottesville, Va.

Dear Mike,

The short answer is that some winemakers have considered it. But the jury is still out on its utility. Way out.

Resveratrol is a natural component of grapes, especially red grapes, and is also present in wine. Recent scientific research has suggested that resveratrol may have very desirable health benefits, from fighting cancer to slowing aging. But these are very preliminary results, and to consume the amounts of resveratrol required to produce these effects in rats, for example, humans would have to drink hundreds of glasses of wine each day (at which point you'd have far more problems than resveratrol could help you with).

The amount of resveratrol in wine varies by the grape variety as well as the winemaking process. Pectolytic enzymes, which can be used to break down grape skins, have been marketed to winemakers as being able to increase the extraction of resveratrol. If resveratrol is in grape skins, and this enzyme breaks down the skins, then using the enzyme should produce more resveratrol, right? But a UC Davis professor says that this application of the enzyme hasn't been proven yet, and he has suspicions that it won't work—and that even if it did work, it might alter the wine, changing the flavor and adding tannins.

Some winemakers out there are experimenting with these enzymes, but with the government regulating what claims can be made on products about their health benefits, we're a long way off from seeing "Now With More Resveratrol!" stickers on our bottles of wine.

—Dr. Vinny

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