Pica is the compulsive eating of non-nutritive substances. It is often associated with iron deficiency but its pathophysiology is unknown. Areas covered: We searched the literature using the keywords listed below. Our aim was to describe the phenomenon in its various aspects, to touch briefly on the historical and cultural background, and to examine in more detail the studies that tried to analyze the relative roles of iron deficiency and pica. Expert commentary: Pica is an intriguing symptom known for centuries. Pregnant women and preadolescents are at the highest risk of pica. Iron absorption is reduced in the presence of non-nutritive substances. Iron therapy usually cures the pica behavior. There are different forms of pica, one caused directly by iron deficiency probably due to the lack of iron in some areas of the brain and one more culturally driven and including mostly geophagy.
Keywords: Geophagy; iron deficiency; pagophagia; pica.