Q. If you don't drink wine, can you get the same antioxidants from purple grapes or dark grape juice?

A. Red wine seems to have the edge over grapes and grape juice for a couple of reasons. Firstly you need to know that the antioxidants in grapes and wine are known as phenolic compounds (as their structure is based on phenol). In grapes, these phenolic compounds are located largely in the skins and seeds.

Red wine contains more phenolics than grape juice because the process of wine-making liberates these compounds into the wine from the skins and seeds during fermentation. Some research suggests that the alcohol in wine (or the process of wine-making itself) also improves their absorption from the intestine into the bloodstream.

White wines are generally fermented without skins, so end up with fewer phenolic compounds in the wine. There is about a six-fold difference in the amount of phenolic compounds between red and white wine.

Second, the other feature of wine compared to grape juice is simply the alcohol itself. Alcohol has separate and beneficial effects on your heart and circulation due to its ability to increase the 'good' HDL-cholesterol and reduce blood clotting.

And how many grapes would you have to consume to achieve the same effect as a glass of red wine? No one knows for sure, as it would depend on the variety and time of harvest. Clearly it is a large quantity of red/purple grapes, probably around half a kilo (one pound) or more a day, which may not be acceptable unless you adored grapes or grew them yourself!

Remember that red wine is not the only source of antioxidants in the diet. If you don't currently drink, you don't have to take it up to be healthy. Vegetables, fruits, onions, garlic, tea and dark chocolate also contribute a variety of antioxidants, which all help.