Flavonoids are polyphenolic compounds ubiquitous in fruits and vegetables. They appear in especially high concentrations in the form of flavanols in green tea as well as in cocoa, and are known to have beneficial antioxidant effects in vitro. Flavonoids have been proposed as a key protective dietary component, reducing the risk of coronary heart disease, including the reduction of elevated blood pressure in persons with hypertension and capable of decreasing LDL.