Iron Deficiency


Iron deficiency is a leading cause of anaemia, affecting more than half a billion people worldwide. Depletion of iron stores precedes impaired production of ironā€containing proteins, most importantly haemoglobin. The two important stages of iron deficiency are (1) depletion of iron stores without anaemia and (2) depletion of iron stores with anaemia. The gastrointestinal tract mediates iron uptake into the body but is also the major source of iron loss and iron deficiency. Although anaemia is the most commonly recognised consequence of iron deficiency, injury to other organs has serious consequences that include fatigue, weakness and developmental delay in infants. Maternal iron deficiency during pregnancy can result in poor neonatal low iron stores and heightened risk of neurocognitive impairment. Oral iron supplements are the most convenient form of replacement but attention should be directed to the preparation as tolerance varies greatly depending on the specific iron salt.

Key Concepts

  • Iron is the second most common metal in the surface of the earth, but absorption is a challenge due to the low solubility of iron salts.
  • Gastric acidity and weak iron chelators, such as ascorbic acid, greatly facilitate iron absorption that occurs primarily in the duodenum and upper jejunum.
  • Gastrointestinal blood loss is the most common cause of iron deficiency.
  • Females of reproductive age suffer a high rate of iron deficiency due to menstrual blood loss.
  • Iron deficiency often produces anaemia in which extremely low haemoglobin levels are tolerated because of the slow rate of fall from the normal range.
  • Growth and developmental delay are particularly serious consequences of iron deficiency during infancy, often occurring in the wake of substantial maternal iron deficiency during gestation.
  • Oral iron is the most convenient form of replacement but often is poorly tolerated when sulphate is the anion in the salt.
  • A dramatic decline has occurred in serious complications of intravenous iron replacement, including anaphylaxis, with the advent of newer formulations.

Keywords: iron; anaemia; haemoglobin; bleeding; fatigue

Figure 1. Photomicrograph of microcytic, hypochromic red cells in a patient with iron deficiency.
Figure 2. Effect of iron deficiency on circulating iron and haematocrit. The number of red cells falls because there is insufficient iron to maintain haematopoiesis. The quantity of transferrin in the circulation rises while the amount of iron falls. The transferrin saturation (the ratio of plasma iron to transferrin) consequently falls as well.


Adamson J (1994) The relationship of erythropoietin and iron metabolism to red blood cell production in humans. Seminars in Oncology 21: 9–15.

Auerbach M, Strauss W, Auerbach S, et al. (2013) Safety and efficacy of total dose infusion of 1,020 mg of ferumoxytol administered over 15 minutes. American Journal of Hematology 88: 944–947.

Brugnara C, Colella G, Cremins J, et al. (1994) Effects of subcutaneous recombinant human erythropoietin in normal subjects: development of decreased reticulocyte hemoglobin content and iron‐deficient erythropoiesis. Journal of Laboratory and Clinical Medicine 123: 660–667.

Corazza GR, Valentini RA, Andreani ML, et al. (1995) Subclinical coeliac disease is a frequent cause of iron‐deficiency anaemia. Scandanavian Journal of Gastroenterology 30: 153–156.

Hopkins RM, Gracey MS, Hobbs RP, et al. (1997) The prevalence of hookworm infection, iron deficiency and anaemia in an aboriginal community in north‐west Australia. Medical Journal of Australia 166: 241–244.

Lin C, Lin J, Chen S, Jiang M and Chiu C (1992) Comparison of hemoglobin and red blood cell distribution width in the differential diagnosis of microcytic anemia. Archives of Pathology and Laboratory Medicine 116: 1030–1032.

Lozoff B, Jimenez E and Wolf A (1991) Long‐term developmental outcome of infants with iron deficiency. New England Journal of Medicine 325: 687–694.

Oski F (1993) Iron deficiency in infancy and childhood. New England Journal of Medicine 329: 190–193.

Roselle H (1970) Association of laundry starch and clay ingestion with anemia in New York City. Archives of Internal Medicine 125: 57.

Rutherford C, Schneider T, Dempsey H, et al. (1994) Efficacy of different dosing regimens for recombinant human erythropoietin in a simulated perisurgical setting: the importance of iron availability in optimizing response. American Journal of Medicine 96: 139–145.

Further Reading

Bini EJ, Micale PL and Weinshel EH (1998) Evaluation of the gastrointestinal tract in premenopausal women with iron deficiency anemia. American Journal of Medicine 105: 281–286.

Bridges KR and Pearson HA (2007) Iron Deficiency. In: Anemia and Other Red Cell Disorders, pp. 97–131. New York: McGraw‐Hill.

Pollitt E, Saco‐Pollitt C, Ceibel RC and Viteri FE (1986) Iron deficiency and behavioral development in infants and preschool children. American Journal of Clinical Nutrition 43: 555–565.

Stoltzfus RJ, Dreyfuss ML, Chwaya HM and Albonico M (1997) Hookworm control as a strategy to prevent iron deficiency. Nutrition Reviews 55: 223–232.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Bridges, Kenneth R(Feb 2015) Iron Deficiency. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0002277.pub2]