Catechins are bioavailable in men and women drinking black tea throughout the day

Tea consumption has been associated with reduced risk of both cancer and ca rdiovascular disease in population studies, but clinical data demonstrating bioavailability of the individual catechins and other polyphenolic compone nts of tea are limited. This study assessed the apparent bioavailability of the prominent catechins from black tea in humans drinking tea throughout t he day. After 5 d of consuming a low flavonoid diet, subjects drank a black tea preparation containing 15.48, 36.54, 16.74, and 31.14 mg of (-)-epigal locatechin (EGC), (-)-epicatechin (EC), (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG), respectively, at four time points (0, 2 , 4 and 6 h). Blood, urine and fecal specimens were collected over a 24- to 72-h period and catechins were quantified by HPLC with coularray detection . Plasma concentrations of EGG, EC and EGCG increased significantly relativ e to baseline (P < 0.05). Plasma EGG, EC and EGCG peaked after 5 h, whereas ECG peaked at 24 h. Urinary excretion of EGC and EC, which peaked at 5 h, was increased relative to baseline amounts (P < 0.05) and fecal excretion o f all four catechins was increased relative to baseline (P < 0.05). Approxi mately 1.68% of ingested catechins were present in the plasma, urine and fe ces, and the apparent bioavailability of the gallated catechins was lower t han the nongallated forms. Thus, catechins were bioavailable. However, unle ss they are rapidly metabolized or sequestered, the catechins appeared to b e absorbed in amounts that were small relative to intake.