ABSTRACT
Iron is an essential element for all living organisms and appropriate iron balance is necessary for survival. The absorption of iron by the small intestine is a process tightly linked to the body's iron needs. This tight linkage is necessary because the human has only very limited capacity to excrete iron. In Western societies, both iron overload and iron deficiency are significant problems, whereas in developing countries the problem of iron deficiency predominates. The relationship between serum ferritin concentration and iron stores as measured by quantitative phlebotomy has been confirmed in subsequent studies. A very strong inverse relationship has been demonstrated between body iron stores and absorption. Iron absorption is enhanced when erythropoiesis is stimulated by bleeding or acute hemolysis. Hypoxia is associated with an increase in iron absorption independent of changes in the rate of erythropoiesis. Incorporation of iron into mucosal ferritin is highest when body iron stores are high and lowest during iron deficiency.
