Nuclear magnetic resonance spectroscopic based studies of the metabolism of black tea polyphenols in humans.

Epidemiological studies indicate that a high intake of flavonoids is associated with an improved health status. Tea is one of the most abundant sources of flavonoids in the human diet. The bioavailability and biotransformation of tea flavonoids are, however, not clearly understood.

Chlorogenic acid, quercetin-3-rutinoside and black tea phenols are extensively metabolized in humans.

Dietary phenols are antioxidants, and their consumption might contribute to the prevention of cardiovascular disease. Coffee and tea are major dietary sources of phenols. Dietary phenols are metabolized extensively in the body.