New evidence on the effects of tea on mercury metabolism in humans

The authors present the results of an experiment in which they explored the role of tea in human metabolic processing of methylmercury (MeHg) from fish consumption. The experiment involved 50 scientists from the Collaborative Mercury Research Network (COMERN) who agreed to eat fish for 2 daily meals for 3 consecutive days. Half of the participants also drank 6 cups of tea daily, starting a week before and continuing through the experiment. The authors calculated the total amount of MeHg that each participant ingested from (1) the measured mercury (Hg) level in fish and (2) the quantity of fish eaten, and compared it with the total increases of Hg and MeHg levels in participants' blood. Results indicated that the control group metabolized roughly 100% of the available fish MeHg, whereas the tea-exposed group showed blood levels of MeHg at more than 40% than that available in the fish provided, suggesting that an external MeHg pool supplied part of the measured blood MeHg increase. The authors conclude that tea may accelerate the enterohepatic MeHg cycle and contribute to a temporary bioamplification of MeHg in the bloodstream.