Regulation of iron equilibrium occurs mainly through the process of absorption. Iron is absorbed through the mucosal cells lining the duodenum. A variety of proteins are involved in this process. Hepcidin, an antimicrobial protein primarily produced in the liver, has recently been found to be a significant (negative) regulator of dietary iron absorption by disrupting cellular iron transport in the intestine. Decreased levels of hepcidin are related to increased iron absorption into the bloodstream. Hepcidin is increased in response to iron overload and inflammation.5
Additional proteins involved in iron metabolism include transferrin (Tf), transferrin receptor (TfR), ferroportin, HFE protein, hemojuvelin, and others. Their roles in iron absorption are complex and, in some instances, not completely understood.
