How do we demonstrate that there is a potential therapeutic role for moderate wine consumption?

The light to moderate consumption of alcoholic beverages has been observed to reduce the risk of, and death from, cardiovascular disease (CVD) by potentially 20-50% compared to abstention and excessive consumption. The main component considered responsible for the reduced risk is ethanol. One of the alcoholic beverages, wine, additionally contains phenolic compounds, that are also observed in fruits and vegetables, the consumption of which is associated with a similar reduced risk of CVD. It has thus been proposed that consumers of wine have a greater reduction in the risk of CVD than do consumers of beer and spirits, but potential confounders include the drinking pattern and associated diet and lifestyle of consumers. What is perplexing scientists, however, is the amount of phenolic compound that is necessary to elicit a cardioprotective effect e.g. on platelet aggregation or coagulation. In in vitro studies effects are generally elicited with a 10- or 100-fold greater concentration of phenolic compounds than is present in blood and at cellular sites of action following moderate consumption. This suggests that the metabolites of phenolic compounds may also be bioactive. This paper reviews the data generated to date on the amount of phenolic compounds necessary to elicit certain cardioprotective effects, and whether isolated individual phenolic compounds are as effective as those administered in a wine medium. The data suggests that although the phenolic compounds are absorbed into the blood stream in measurable amounts, the metabolite is more likely to be the biologically active compound in vitro. Furthermore, when seed-derived phenolic compounds are together with the skin and flesh-derived phenolic compounds in wine, they exhibit greater cardioprotective effects than when present individually in a non-wine medium and are potentially equipotent to certain conventional pharmaceutical products at reducing the risk of CVD.