Tea consumption does not affect iron absorption in rats unless tea and iron are consumed together

Abstract

Phenolic compounds may influence iron absorption by complexing iron in the intestinal lumen or by altering intestinal permeability. We assessed the effects of tea on iron absorption and intestinal permeability in rats in two experiments. In experiment 1, rats maintained on a commercial rat diet were fasted overnight with free access to water and then gavaged with 1.0 ml of 59Fe labeled FeCl 3 (0.1 mM or 1.0 mM) and lactulose (0.5 M) in water or black tea. Iron absorption was estimated from 59Fe retention. Intestinal permeability was evaluated by lactulose excretion in the urine. Iron absorption was lower when given with tea at both iron concentrations but tea did not affect lactulose excretion. In experiment 2, rats maintained on a commercial rat diet were divided into two groups. One group was given black tea as the only source of water for 3 d. The other group was given water. Both groups were fasted overnight with free access to water and then gavaged with 1.0 ml of water or black tea containing 59Fe labeled FeCl 3 (0.1 mM) and lactulose (0.5 M). Iron absorption was not affected by 3 d of tea consumption but was decreased when delivered in tea. Lactulose excretion was not affected by 3 d tea consumption or by delivery in tea. These data suggest that tea affects iron absorption by forming iron complexes in the lumen.