Green tea does not inhibit iron absorption

Abstract

⁎ Tel.: +1 202 741 2426; fax: +1 202 741 2324. E-mail address: tcheng@mfa.gwu.edu. A recent inquiry from a journalist prompted me to write this Letter to the Editor. In some parts of the world, there is a belief that green tea may inhibit iron absorption and thus result in iron deficiency anemia. Unfortunately, this is not supported by any scientific evidence. In Japan, it is sometimes said that ingestion of green tea should be avoided before and after the intake of iron preparation [1]. However, two groups of Japanese investigators showed this not to be true [1,2]. Mitamura and associates [1] administered sodium ferrous citrate to pregnant women with anemia who were divided into two groups: one taking green tea and the other taking water. They found that anemia was corrected in 97% of patients in the green tea group and in 93% of patients in the water group after the oral administration of the iron preparation to both groups. Kubota and associates [2] administered the same iron preparation to four elderly patients with iron-deficiency anemia and 11 healthy elderly subjects. In both groups, the serum iron level reached a maximum value 2–4 h after taking sodium ferrous citrate and returned to the baseline values after 24 h [2]. A more recent study was carried out in France on a much larger group of subjects [3]. A total of 954 men (aged 52– 68 years) and 1639 women (aged 42–68 years), who were participant of the SU.VI.MAX (SUpplementation en VItamines et Mineraux AntioXydants) study [4], completed a detailed questionnaire on tea consumption. To determine the iron status of the participants, the investigators measured the serum ferritin level in the venous blood of the participants. They found that the mean serum ferritin concentration was not related to black, green and herbal tea consumption in men, pre-and post-menopausal women. Furthermore, the risk of iron depletion was in the multivariate model not related to any kind of tea drinking or to the strength of tea, the infusion time or the time of tea drinking. Therefore, they concluded that normal apparently healthy adults are not at risk of iron depletion from tea drinking [3]. The only reference that I could find in the literature about a negative effect of tea drinking on iron absorption came from Tunisia [5]. But the experiment was carried out on rats. Therefore, unless you are a rat and a rat in Tunisia, you should not worry about development of iron deficiency anemia from tea drinking. In China tea has been considered a crude medicine for over 4000 years [6]. In my recent review, the health benefit of drinking Chinese green tea on the cardiovascular system has been conclusively demonstrated [6]. Therefore, another ancient Chinese wisdom about green tea is certainly more than just a tempest in a teapot [6].