Quercetin may be a major reason why the old adage about eating "an apple a day" has been associated with good health. And why a daily cup of tea is more than a comforting ritual. Quercetin, which is primarily found in apples, onions, and black tea, is a type of flavonoid (plant pigment) that serves as a building block for other members of the flavonoid family.
Quercetin and other dietary flavonoids have been receiving good health-related press in recent years, and for good reason.
Health Benefits
Quercetin appears to help fight a host of disorders, from asthma to cancer to heart disease. As an antioxidant, it combats the destructive "free radical" molecules that play a part in many diseases. Among people with high dietary intakes of quercetin and other major flavonoids, studies show lower rates of stomach, lung, pancreatic, and breast cancers. Quercetin inhibits the buildup of a type of blood sugar that could otherwise lead to cataract formation in the lens of the eye.
The latest findings indicate that quercetin and other flavonoids may also help to prevent heart attacks. The Rotterdam Study, published in the 2002 American Journal of Clinical Nutrition, examined the tea-drinking habits and dietary flavonoid intakes of nearly 5,000 adults in Holland. Apparently due to black tea's high flavonoid concentration, daily consumption of the brew reduced the risk of heart attack overall for tea drinkers
