Because it is difficult to excrete iron once it is in the body, iron balance is maintained primarily through absorption. The iron storage protein captures iron from food and stores it in the mucosal cells of the small intestine. When the body needs iron, the storage protein releases some iron to an iron transport protein called . If the body does not need iron, the dietary iron is carried out when the intestinal cells are shed (every 3 to 5 days) and excreted in the feces.

True or False

At physiological pH ferrous iron is rapidly oxidized to the insoluble ferric form
Gastric acid lowers the pH in the duodenum which enhances the solubility and uptake of ferric iron
Once iron gets inside the enterocyte it can be stored as ferritin;Ferritin is a hollow spherical protein which helps in storage and regulation of iron levels within the body
Ferritin molecule have ferroxidase activity which helps in the mobility of Fe2+ out of the enterocyte by ferroportin
Transferrin is the major iron transport protein which transports iron through blood
Fe3+ binds to transferrin so Fe2+ transported through ferroportin must be oxidized to Fe3+
Fe2+ needs to be oxidized first so that it can be transported through ferroportin
Once iron gets inside the cell it can be used for various cellular processes