Iron Deficiency

Iron (Fe) is a component of hemoglobin, myoglobin, and many enzymes in the body. Heme iron is contained mainly in animal products. It is absorbed much better than nonheme iron (eg, in plants and grains). Nonheme iron 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.

(See also Overview of Mineral Deficiency and Toxicity Overview of Minerals Six macrominerals are required by people in gram amounts. Four cations: Sodium, potassium, calcium, and magnesium Two accompanying anions: Chloride and phosphorus Daily requirements range from... read more .)

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 and older people.

Iron deficiency and iron deficiency anemia Iron Deficiency Anemia Iron deficiency is the most common cause of anemia and usually results from blood loss; malabsorption, such as occurs in celiac disease, is a much less common cause. Symptoms are usually nonspecific... read more are common among elite runners and triathlon athletes (1 General references Iron (Fe) is a component of hemoglobin, myoglobin, and many enzymes in the body. Heme iron is contained mainly in animal products. It is absorbed much better than nonheme iron (eg, in plants... read more ).

Chronic kidney disease Chronic Kidney Disease Chronic kidney disease (CKD) is long-standing, progressive deterioration of renal function. Symptoms develop slowly and in advanced stages include anorexia, nausea, vomiting, stomatitis, dysgeusia... read more and inflammatory bowel disease Overview of Inflammatory Bowel Disease Inflammatory bowel disease (IBD), which includes Crohn disease and ulcerative colitis, is a relapsing and remitting condition characterized by chronic inflammation at various sites in the gastrointestinal... read more are also associated with iron deficiency. In patients with chronic kidney disease, including those on hemodialysis and those with inflammatory bowel disease or other chronic inflammatory conditions, hepatic synthesis of the hormone hepcidin is increased, interfering with iron absorption and leading to iron deficiency. However, chronic inflammation also increases serum iron by decreasing the use of iron to make red blood cells and thus causes anemia of chronic disease Anemia of Chronic Disease The anemia of chronic disease is a multifactorial anemia. Diagnosis generally requires the presence of a chronic inflammatory condition, such as infection, autoimmune disease, kidney disease... read more and complicates the assessment of iron status.

When iron deficiency is advanced, microcytic anemia Iron Deficiency Anemia Iron deficiency is the most common cause of anemia and usually results from blood loss; malabsorption, such as occurs in celiac disease, is a much less common cause. Symptoms are usually nonspecific... read more develops.

In addition to anemia, iron deficiency may cause pica Pica Pica is persistent eating of nonnutritive, nonfood material for ≥1 month when it is developmentally inappropriate (eg, pica is not diagnosed in children < 2 years) and when it is not part... read more (a craving for nonfoods) and spoon nails and is associated with restless leg syndrome Periodic Limb Movement Disorder (PLMD) and Restless Legs Syndrome (RLS) Periodic limb movement disorder (PLMD) and restless legs syndrome (RLS) are characterized by abnormal motions of and, for RLS, usually sensations in the lower or upper extremities, which may... read more . Rarely, iron deficiency causes dysphagia Dysphagia Dysphagia is difficulty swallowing. The condition results from impeded transport of liquids, solids, or both from the pharynx to the stomach. Dysphagia should not be confused with globus sensation... read more due to postcricoid esophageal web.

Iron deficiency may exacerbate some types of heart failure; in such cases, patients may benefit from iron replacement (2 General references Iron (Fe) is a component of hemoglobin, myoglobin, and many enzymes in the body. Heme iron is contained mainly in animal products. It is absorbed much better than nonheme iron (eg, in plants... read more ).

Diagnosis of iron deficiency involves complete blood count, serum ferritin and iron levels, and possibly measurement of transferrin saturation (iron-binding capacity). In deficiency states, iron and ferritin levels tend to be low, and iron-binding capacity tends to be high (3 General references Iron (Fe) is a component of hemoglobin, myoglobin, and many enzymes in the body. Heme iron is contained mainly in animal products. It is absorbed much better than nonheme iron (eg, in plants... read more ).

Rarely, when the diagnosis of iron deficiency remains uncertain, examination of bone marrow for iron may be necessary.

Treatment of iron deficiency involves correcting the cause if possible (eg, treatment of a bleeding intestinal tumor). All people with moderate or severe iron deficiency and some people with mild deficiency require iron supplementation Treatment Iron deficiency is the most common cause of anemia and usually results from blood loss; malabsorption, such as occurs in celiac disease, is a much less common cause. Symptoms are usually nonspecific... read more .