Regulation of iron absorption, transport, and homeostasis

Schematic showing iron homeostasis. Fe circulates bound to transferrin, which receives most Fe from macrophages that phagocytize senescent RBCs and by enterocytes that absorb a minimal amount of dietary iron, to compensate for the amount of iron lost through cell desquamation and blood loss. Most Fe is supplied to the bone marrow for RBC production. Excess Fe is stored in the liver and macrophages as a reserve. Numbers (in mg) are an estimate of the mean amount of Fe in various compartments. Refer to UpToDate for details.