Flavonols in wine and tea and prevention of coronary heart disease

Tea and red wine are both important sources of dietary flavonols. The consumption of tea, wine and flavonols have been associated, though not consistently, in epidemiological studies with a lower risk of coronary heart disease. In vitro studies suggest that flavonols lower the susceptibility of low-density cholesterol to oxidation and that flavonols may reduce platelet aggregation. Both mechanisms are thought to play an important role in the development of coronary heart disease and stroke in humans. However, a number of human experimental studies conducted with wine, tea or flavonols themselves failed to confirm unequivocally these in vitro findings. A major drawback in interpreting these studies that only little is known about the absorption of flavonols from these foods, and the factors affect absorption rates. Although the evidence from epidemiology thus far is compatible with a protective effect of antioxidant flavonols, more information is needed on the actual effects of flavonols, tea and wine in the human body. In addition tea and wine contain also other antioxidant substances such as the catechins which could in part explain their potential health effects. However, only little is known about catechins and their effects in the human body.