Recently I read a newspaper article in on geophagia. This phenomenon has fascinated me since medical school. I recall making mud pies as a child, decorating them with Queen’s Anne Lace and Black-eyed Susans. We never thought to eat them.
Geophagia is a type or subgroup of pica. Pica (from the Latin name for magpie, a bird known for its unusual and indiscriminate eating habits) is the persistent craving and compulsive eating of nonfood substances. It is classified in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, as a feeding and eating disorder of childhood. It may begin in childhood, but does not always get left there.
Pica has been recognized and described since ancient times. It has been observed in ethnic groups worldwide, in both primitive and modern cultures, in both sexes, and in all age groups. Pica has also been observed in other animals, including the chimpanzee. There is a higher incidence of pica in pregnant women, iron deficient individuals, early childhood, and certain cultural and religious groups.
Pica in humans has many different subgroups, defined by the substance that is ingested. Some of the most commonly described types of pica are eating earth, soil or clay (geophagia), ice (pagophagia) and starch (amylophagia). However, pica involving dozens of other substances, including cigarette butts and ashes, hair, paint chips, and paper have also been reported.
Evidence suggests that there may be several causes of pica. One widely held theory points to iron deficiency as a major cause of pica. Several reports have described pica in individuals with documented iron deficiency. It remains uncertain as to whether the iron deficiency caused the pica or is a result of the pica (chicken and egg problem). Because some substances, such as clay, are believed to block the absorption of iron into the bloodstream, it was thought that low blood levels of iron could be the direct result of pica.
Other reports suggest that pica may have a psychological basis and may even fall into the spectrum of obsessive-compulsive disorder. Pica has a higher incidence in populations with an underlying diagnosis involving mental functioning. These diagnoses include psychiatric conditions like schizophrenia, developmental disorders including autism, and conditions with mental retardation. These conditions are not characterized by iron deficiency, which supports a psychological component in the cause of pica.
Cultural and religious traditions may also play a role in pica behavior. It seems that the tradition may be dying out, as the more recent generations are not picking up the habit of geophagia here in the south (US). In some cultures, nonfood substances are believed to have positive health or spiritual effects. Among some African Americans in the south, ingesting a particular kind of white clay is believed to promote health and reduce morning sickness during pregnancy. Other cultures practice pica out of belief that eating a particular substance may promote fertility or bring good luck.
Because the eating behaviors of pica are not usually detected or reported, it is the complications of the behavior that bring it to attention. Complications vary, depending on the type of pica. Geophagia has potential side effects that most commonly affect the intestine and bowel. Complications can include constipation, cramping, pain, obstruction caused by formation of an indigestible mass, perforation from sharp objects like rocks or gravel and contamination and infection from soil-dwelling parasites.