Normal Iron Metabolism: If the body absorbs enough of the right nutrients, a well-balanced diet will be achieved. Approximately 2 mg of iron is lost daily due to epithelial sloughing. Iron is mainly lost at a more drastic rate during menstrual cycles, bleeding. During pregnancy, there is a greater demand for iron, which also increases iron absorption by up to 20%. The two main sites of iron absorption are the duodenum and the upper duodenum. The divalent metal transporter transports absorbed iron across intestinal epithelial cells. Metals such as manganese, copper, cobalt and zinc (good metals), cadmium, lead (bad metals) are also transported by the carrier. An erythrocyte releases iron through a passage called ferroportin and into the bloodstream. Transferrin (transport protein) binds iron in the bloodstream. During the metabolic process, between 20 and 45% of transferrin sites are full. Very little of the bound iron formed (0.1%) throughout the body goes to transferrin. All absorbed iron is used for erythropoiesis in t...