Resveratrol: a wonder drug in wine
There have been a couple of recent scientific reports on resveratrol that have attracted a lot of interest. It's a phytoalexin that is found in grape skins (and thus wine). If it is fed to mice at reasonably high doses, it protects them from the negative effects of eating too much. It's quite dramatic: these mice can eat a high fat diet that would normally kill them pretty sharpish, but when they are given a stiff resveratrol chaser with their rations, they don't get fat, don't develop diabetes, and consequently don't keel over prematurely. It seems that resveratrol hits a particular metabolic switch, giving you the benefits of dieting and excercise without actually doing either.
As you can understand, this has got people pretty excited. As long as you drink a few glasses of resveratrol-rich wine, then you can carry on gorging yourself on fine French cuisine, and forget about pounding the pavements in an attempt to stem a bulging waistline and incipient type 2 diabetes. But wait a minute: the story isn't that simple.
I asked Professor Roger Corder, who has researched wine and health, for his views.
‘The resveratrol story has become a bit of a publicity stunt for those lacking knowledge in the field’, maintains Corder. ‘At a dose of 22.4 mg/kg per day (used in the recent mouse study reported in Nature) and typical resveratrol levels of 1–2 mg/litre in wine, the dose in human terms for wine would have to be around 1568 mg/day or 780–1560 litres per day’.
Also problematic is the bioavailability story. Data in humans are currently rather limited, although they are beginning to emerge. And they threaten to rain on the resveratrol parade. Professor Thomas Walle at the Medical University of South Carolina published a rather damning paper on this in 2004, in which he concluded that in humans very little dietary resveratrol gets to where it is needed in the body. ‘Based on our studies as well as those of others the bioavailability of resveratrol, that is the amount intact resveratrol reaching the blood circulation, is virtually zero in humans’, reports Walle.