More on wine antioxidants
Just thought I should expand a bit on my post on the new Red Heart wine. The wine in question is a Petit Verdot/Cabernet Sauvignon from South Australia, bottled in Northants (UK) by Corby for Buckingham Vintners.
The label states that:
'Antioxidants can help inhibit free radicals that occur naturally in your body. Free radicals can damage your health, so a wine that's naturally high in antioxidants has got to be great news!'This statement cleverly avoids making the claim that the antioxidants in this wine will protect you against free radical oxidative damage to the tissues of your body, but this is implied. Let me make the following points:
- All the big epidemiological studies (where medics look at the health of populations) show that moderate drinkers live longer. Some studies show that wine drinkers are healthier than beer or spirit drinkers. Some of this could be confounding (for example, there might be some other shared characteristic of moderate drinkers or wine drinkers that makes them a more healthy group). But the effect looks pretty robust.
- Many mechanisms have been proposed for how wine (or other alcoholic drinks) might have health-enhancing effects. One of these is that wine, and in particular red wine, contains a group of compounds known as polyphenols, which have anti-oxidant properties. Although we need oxygen, itís actually quite a toxic molecule, and a group of chemicals known as reactive oxygen species cause damage to our body tissues (although they also have a role in fighting microbes). We have various antioxidant defences in our tissues which minimizes the impact of these bad dude chemicals. Damage still occurs, though. So the idea that red wine polyphenols could be enhancing antioxidant protection is a seductive one.
- Thereís a problem, though. Dietary antioxidants donít seem to work as antioxidants in the body in the same way that they do in the test-tube. The emerging story is that it is increasingly unlikely that any of wineís health benefits come from the antioxidant effects of polyphenols.
- It looks like polyphenols may still have a protective effect, but not as antioxidants. One possible mechanism is through their effect in suppressing a molecule called endothelin 1, which would then have a positive effect on arteries and blood vessels. Quite a bit more work needs to be done before we can be sure of this.