Iron Deficiency Problems: More Than Just Anemia

By Alchemist-hp (talk) (www.pse-mendelejew.de) - Own work, FAL, https://commons.wikimedia.org/w/index.php?curid=10115787

Iron deficiency can have harmful effects other than just anemia (which is bad enough); there can be problems with immune and nervous system function, as well as other negative effects.  Abstract:

OBJECTIVE:

To consider the key implications of iron deficiency for biochemical and physiological functions beyond erythropoiesis.

METHODS:

PubMed was searched for relevant journal articles published up to August 2017.

RESULTS:

Anemia is the most well-recognized consequence of persisting iron deficiency, but various other unfavorable consequences can develop either before or concurrently with anemia. Mitochondrial function can be profoundly disturbed since iron is a cofactor for heme-containing enzymes and non-heme iron-containing enzymes in the mitochondrial electron transport chain. Biosynthesis of heme and iron-sulfur clusters in the mitochondria is inhibited, disrupting synthesis of compounds such as hemoglobin, myoglobin, cytochromes and nitric oxide synthase. The physiological consequences include fatigue, lethargy and dyspnea; conversely iron repletion in iron-deficient individuals has been shown to improve exercise capacity. The myocardium, with its high energy demands, is particularly at risk from the effects of iron deficiency. Randomized trials have found striking improvements in disease severity in anemic but also non-anemic chronic heart failure patients with iron deficiency after iron therapy. In vitro and preclinical studies have demonstrated that iron is required by numerous enzymes involved in DNA replication and repair, and for normal cell cycle regulation. Iron is also critical for immune cell growth, proliferation and differentiation and for specific cell-mediated effector pathways. Observational studies have shown that iron-deficient individuals have defective immune function, particularly T-cell immunity, but more evidence is required. Preclinical models have demonstrated abnormal myelogenesis, brain cell metabolism, neurotransmission and hippocampal formation in iron-deficient neonates and young animals. In humans, iron deficiency anemia is associated with poorer cognitive and motor skills. However, the impact of iron deficiency without anemia is less clear.

CONCLUSION:

The widespread cellular and physiological effects of iron deficiency highlight the need for early detection and treatment of iron deficiency, both to ameliorate these non-erythropoietic effects and to avoid progression to iron deficiency anemia.