What is the evidence for iron deficiency causing pica?

Pica refers to the compulsive craving and persistent consumption of substances not fit as food such as ice (pagophagia) and soil (geophagia). Several reports have implicated iron deficiency as a cause of pica, with resolution of symptoms following treatment of iron deficiency (1).

In a recent study involving blood donors , pica (particularly pagophagia) was nearly 3 times as likely among donors with iron deficiency  compared to iron-replete donors (11%  vs 4%, respectively, P<0.0001).  In the same study, donors with pica reported a marked reduction in their pica by day 5-8 of iron therapy. 

It has been suggested that cerebral tissue function may be adversely impacted by a deficiency in Fe-containing enzymes (e.g. cytochrome c reductase) resulting in behavioral disorders, such as hyperactivity and pica (2).  

Of interest, cats can be induced to swallow inedible objects when certain points in the hypothalamic area high in iron content are stimulated (3).

References

  1. Bryant BJ, Yau YY, Arceo SM, et al. Ascertainment of iron deficiency and depletion in blood donors through screening questions for pica and restless legs syndrome. Transfusion 2013;53:1637-1644. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3691288
  2. Osman YM, Wali YA, Osman OM. Craving for ice and iron-deficiency anemia: a case series from Oman. Pediatric Hematol Oncol 2005; 22:127-131. https://www.ncbi.nlm.nih.gov/pubmed/15804997
  3. Von Bonsdorff B. Pica: a hypothesis.. British J Haematol 1977;35:476-477.  https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2141.1977.tb00611.x

 

Contributed by S.J. Lee,  Medical Student, Harvard Medical School, Boston, MA

What is the evidence for iron deficiency causing pica?