Whining about antioxidants

Sounds cute doesn’t it, a gadget that tells you how good that glass of wine is for you?  A Swiss company has produced a device that will measure levels of antioxidants, chemicals found in wine and thought by some to reduce the risk of heart disease and cancer (Scientists unveil device to show wine’s health benefits, Guardian, October 5th , http://www.guardian.co.uk/lifeandstyle/2010/oct/05/device-measure-red-wine-antioxidants).   In the future, according to the article, levels of antioxidants might be given on a bottle of wine and some wines could be labelled as “this drink is good for you”.    

But how good is the science behind these claims?  It’s an emotive and very confusing topic so I had a look at what the British Heart Foundation says about wine and heart disease.  They say that there is evidence suggesting that red wine might be good for heart health but they add the caveat that “this still needs to be substantiated in controlled studies”.  What they are referring to is the gold standard method for establishing effects of a drug or other chemical on humans.  The substance is tested in a randomised manner in a large population versus a control no-drug group.   Controlled trials of the effects of wine are very difficult to perform as wine is not a uniform product.  So the evidence has to come from studies comparing drinking habits and the incidence of heart disease.  Interpretation of these kinds of studies may be difficult as there could be additional factors such as diet that differ between a wine drinking group and a non-wine drinking group.

But if we accept that there is some evidence for a beneficial effect of wine on heart disease is it correct to focus on antioxidants?   Let’s take the British Heart Foundation’s advice here again.  They say that small amounts (1-2 units) of any alcoholic drink taken regularly may offer some protection against heart disease.  If this is true then focussing on the beneficial effects of antioxidants in wine may be misguided and it may be the alcohol that is more important.  But actually this is a very controversial area and some people think that there is something in red wine (antioxidants?) that confers additional protection. 

But let’s look again at the case for antioxidants?  Antioxidants are thought to prevent damage by free radicals associated with heart disease and cancer and it sounds plausible that antioxidant-rich wines would be helpful.   If this is true then it might be expected that any substance that had antioxidant properties would also be beneficial against heart disease or cancer.  Here it is possible to do a meaningful controlled trial as pure antioxidants are available as food supplements and have been carefully tested e.g. vitamins A, C and E.  There is an authoritative review of all the controlled antioxidant trials that have been performed and this review showed that there were no beneficial effects of antioxidants on overall mortality from any cause and in some cases the antioxidants increased mortality.

This doesn’t look very good for the antioxidant hypothesis and it may be that beneficial effects of wine are not associated with antioxidants but are due to its alcohol content.  It would be wrong, however, to recommend consumption of wine as a lifestyle choice to prevent heart disease, especially as drinking more than the recommended limits can have negative effects on the heart and can increase the risk of cancer and other diseases.  There are far safer and healthier ways to protect the heart such as physical activity, eating a healthy and balanced diet and giving up smoking.   We are still some way from labelling wine bottles as “this drink is good for you”.

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