Tea very significantly decreases iron absorption as tannins in tea form insoluble complexes with iron. Iron in iron/tannin-complexes would also not be bioavailable in the gut. Still individuals who drink tea can have normal iron levels. The question is whether blood measures of iron status are a complete picture of iron status. In the proposed experiment rats would be given tea by gavage. Levels of tea given by gavage would not be levels that would cause anemia. What would be tested is the status of aconitase 1 in the gut and the effect of the tea on the citric acid cycle in the gut. Aconitase 1 is regulated by iron levels where with high levels of iron aconitase 1 acts as an aconitase but with low levels of iron aconitase 1 switches to IRP1 which regulates iron regulated proteins. Levels in the gut of citrate synthase, isocitric dehydrogenase and succinate dehydrogenase would would also be tested as iron positively affects these enzymes also. Blood levels of iron would also be tested. The hypothesis is that the effect of tea on the gut in terms of aconitase 1 and other enzymes in the citric acid cycle will be more pronounced than blood levels of iron would indicate.