Iron (Fe) is a component of hemoglobin, myoglobin, and many enzymes in the body. Heme iron, contained mainly in animal products, is absorbed much better than nonheme iron (eg, in plants and grains), which accounts for > 85% of iron in the average diet. However, absorption of nonheme iron is increased when it is consumed with animal protein and vitamin C.
Iron deficiency is one of the most common mineral deficiencies in the world. It may result from the following:
Chronic bleeding due to colon cancer is a serious cause in middle-aged people and the elderly.
When deficiency is advanced, microcytic anemia develops (see Anemias Caused by Deficient Erythropoiesis: Iron Deficiency Anemia).
In addition to anemia, iron deficiency may cause pica (a craving for nonfoods) and spoon nails and is associated with restless leg syndrome. Rarely, iron deficiency causes dysphagia due to postcricoid esophageal web.
Diagnosis involves CBC, serum ferritin, and possibly measurement of transferrin saturation (iron capacity).
All people with moderate or severe iron deficiency and some people with mild deficiency require iron supplementation.
Iron may accumulate in the body because of
Iron overload can also result from an inherited iron overload disease (hemochromatosis—see Iron Overload), a potentially fatal but easily treatable genetic disorder in which too much iron is absorbed. Hemochromatosis affects > 1 million Americans.
An overdose of iron is toxic (see Poisoning: Iron Poisoning), causing vomiting, diarrhea, and damage to the intestine and other organs.
Diagnosis is similar to that for iron deficiency.
Treatment often involves deferoxamine, which binds with iron and is excreted in urine.
Last full review/revision August 2008 by Larry E. Johnson, MD, PhD
Content last modified February 2012