Figure 1 | Distribution of iron within the body.   The normal distribution of iron within the body is shown. Adults typically have 3–5 g in total. About 0.5–2 mg of dietary iron is absorbed each day through the proximal small intestine. This intake is balanced by loss of a similar amount of iron, through blood loss and the sloughing of skin and mucosal cells. Most iron is found in the erythroid bone marrow and in mature erythrocytes, contained within the haem moiety of haemoglobin. Iron for new red-blood-cell synthesis is primarily supplied by reticuloendothelial macrophages, which recycle iron from old red blood cells. Circulating iron is bound to transferrin. Around 0.1% of the total body iron is found in this transit compartment. Transferrin delivers iron to developing erythroid precursors, as well as to other tissues of the body. Stored iron is primarily found in the hepatocytes of the liver. The distribution of iron is altered in response to pregnancy, iron deficiency and iron overload. (TF, transferrin.)

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