jamie goode's wine blog

Wednesday, January 07, 2009

I hate pseudoscience!

I've been researching a piece today on a medical doctor in Australia who has been marketing a range of resveratrol-supplemented wines. It's the sort of subject that is liable to set me ranting.

This is because I hate the abuse of science, and one of the primary areas in which science is abused (in my opinion) is in the field of dietary supplements. And, again, in my opinion, I think that to supplement wine with resveratrol, is moving beyond the current state of good science on this topic.

What's the story? A few years ago some really interesting reports turned up in the literature showing that resveratrol, which is a phytoalexin (plant defence molecule) found in red wine, can affect signalling molecules called sirtuins, which act as a metabolic switch.

This switch can shift the metabolism of a wide range of organisms, from yeasts to mammals, between two different strategies: live short and fast, or long and slow.

It seems that nature has built-in these two different strategies so that organisms can adapt to environments of either feast or famine. Normally, caloric restriction - the only intervention shown to extend lifespan across a range of different organisms - will result in a slow-burn sort of metabolism where organisms just hang in there, waiting for things to improve.

Resveratrol signalling, at least in experimental studies, seems to mimic caloric restriction, and it has been suggested that it could be protective against a range of age-related diseases, including cancer. Scientists are taking this seriously, and there is currently a lot of interest in this molecule, although there are issues with dose and bioavailability (it seems you need more than wine contains for there to be an effect, and also that while it's rapidly taken up by the body, it is also rapidly metabolized).

But while drug development based on initially promising findings is a long road that requires researchers to substantiate their claims by proving safety and efficacy of potential drug targets, the dietary supplements industry isn't bound by such restrictions.

Hence, if you search the internet, you'll find many companies already offering resveratrol-based supplements that claim to have amazing health benefits. I think this is wrong. It's far too early to be making claims for compounds such as resveratrol and marketing resveratrol-enhanced wines in the way that's currently being attempted. The science simply isn't there yet.

I also think it's a mistake to market wine as a 'nutriceutical' in this way. There's good evidence that moderate wine consumption may be good for health; so why the need to add extra things to wine?

Let the research scientists do their work. There are good reasons why the pharmaceutical industry is heavily regulated and that consumers are protected from potentially false claims or dangerous medicines. It's high time that the dietary supplements industry was subjected to the same rigorous scrutiny, because it's an industry that's making billions of pounds a year from peddling products whose efficacy is largely unsubstantiated.

I'm going to stop now because I'm beginning to rant.

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Tuesday, November 28, 2006

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.

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