It’s hardly news that wine contains powerful antioxidants, just like other superfoods including blueberries, acai, and pomegranates. What isn’t so obvious though is how these compounds are absorbed into the body and whether or not they actually do any good. This problem of how food-derived nutrients, along with drugs and supplements, are taken up and delivered to “target” tissues throughout the body is called “bioavailability.” There are numerous compounds that perform miracles in a test tube but just aren’t absorbed very well from the digestive tract when taken orally. Resveratrol is a classic example of this; with more than 3,000 research articles published, it’s considered a fountain of youth in a pill (or a glass of wine) by many, but it turns out to have poor bioavailability. There must be something else in wine that explains its long list of health benefits.
Researchers at 2 universities in Spain provided some insight into the role of wine as an antioxidant in a recent study. They used eight volunteers who consumed a standardized diet low in antioxidants, and compared the antioxidant capacity of their blood plasma with and without the addition of red wine to the diet. Samples were taken at days 2 and 7 of the regimen, during the week with wine and without. A significant increase in antioxidant capacity was observed with wine in the diet, as one would hope. (A similar study was done in Chile several years ago, with similar findings and also noting that wine was better than vegetables high in antioxidant vitamins.) This proves that something in the wine is being absorbed and circulated through the body, and having a positive effect. It is probably not resveratrol though, as previous studies of this type have shown that it does not achieve significant levels in the blood after oral ingestion.
Interestingly, dark chocolate is another superfood that has measurable effects when eaten. In this case, it causes the blood vessels to relax and lowers the blood pressure. The cocoa-derived compounds responsible are much the same as antioxidant molecules found in red wine, known as flavonoids. What is important here is to distinguish between studies that actually test what happens in a clinical experiment from what occurs in a laboratory test. Too many supplements are rushed to market based on an incomplete understanding of how they actually work in the human body. It seems we always come back to the point where drinking wine and eating the right foods works better than popping pills. Who would have thought?