Iron is involved in the transport of oxygen and cellular respiration as a component of hemoglobin, myoglobin and the enzymes: cytochrome oxidase, peroxidase and catalase.
In the gut, ferric iron is converted to ferrous iron (the soluble form) in the presence of the acidic pH of the stomach. Luminal iron-binding proteins facilitate the absorption of iron across the intestinal mucosa. Iron is stored in the body as ferritin and hemosiderin in the liver, bone marrow and spleen. A significant portion of iron in the body is a component of hemoglobin and myoglobin. The remainder is bound to iron transport proteins and enzymes.
Heme iron is best absorbed and is found in red meats and liver, heart and kidney. Less bioavailable sources of iron include green leafy vegetables and whole grain cereals.
A deficiency of iron may lead to anemia with physical signs including weakness, fatigue, poor work performance and changes in behaviour. In infants, iron is necessary for brain growth and a deficiency may lead to irreversible developmental delays.