Comparison of catechin profiles in human plasma and urine after single dosing and regular intake of green tea (Camellia sinensis)

Green tea (Camellia sinensis) catechin profiles in plasma and urine following single dosing and regular ingestion of green tea are not clear. We performed a placebo-controlled intervention study with sixteen healthy volunteers to determine changes in total and free catechins after a single dose and following 1 week of twice-daily green tea. Blood and urine samples were collected before (fasting) and after (60 and 120 min for blood; 90 and 180 min for urine) drinking 200 ml of 1·5 % (w/v) green tea or water (n 8 each), and fasting samples were again collected after 7 d of 150 ml of 1 % (w/v) supplemental green tea or water twice daily. After a 4-week washout, subjects were crossed onto the other treatment and procedures repeated. Plasma results at 1 h post-ingestion showed elevated (P