Iron Deficiency
Kenneth R Bridges, Brigham and Women's Hospital, Boston, Massachusetts, USA
Published online: February 2015
DOI: 10.1002/9780470015902.a0002277.pub2
Abstract
Iron deficiency is a leading cause of anaemia, affecting more than half a billion people worldwide. Depletion of iron stores
precedes impaired production of ironācontaining 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
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