The compulsion to eat what’s inedible is known in the medical world as pica (pronounced “PIE-ka”). This is the Latin word for magpie, a bird with a reputation for eating practically anything. Human magpies, according to the medical literature, have been known to eat paper, and a lot more besides: dirt, ashes, starch, matches, cardboard, hair, laundry detergent, chalk and soap, among other things.
This little girl is not alone. Many people, for reasons that are not entirely clear to scientists, eat these nonnutritive substances.
A recent study by the Agency for Healthcare Research and Quality found that hospitalizations for pica in a 10-year span jumped 93 percent, from 964 in 1999-2000 to 1,862 in 2008-2009.
It is difficult to say how common pica is, since most people don’t report it. Nearly all medical journal articles about pica call the condition “underreported” and “unrecognized.” Perhaps it is because patients fear the quizzical look and follow-up question: “You’re eating what?”
According to some studies, more than 50 percent of kids age 18 to 36 months seek and ingest non-food items. The practice is reported to decrease as a kid ages, but one study suggested that about 10 percent of children older than 12 may engage in pica.
And as common as it may be in kids, it is also an ancient practice: Reports and academic studies from antiquity describe “geophagia,” essentially, eating dirt. Dirt is, in fact, the favorite among pica eaters, especially in the United States, where the habit seems concentrated among small children and women who are native to the South, African American or pregnant.
Scientists and anthropologists studying pica have come up with several hypotheses about the cause of these cravings. They include stress, learned behavior, mental health issues and nutritional deficiencies (although the evidence for the last of these is not very strong). Some studies have pointed to an association between pica and deficiencies in iron, calcium, zinc and other nutrients such as thiamine, niacin and vitamins C and D. One explanation, offered in a recent article in the Quarterly Review of Biology, suggests that eating dirt may “protect the stomach against toxins, parasites, and pathogens.”
In addition to being common among young kids, many instances of pica are seen in people with developmental disabilities and autism. As a result, it is often considered a psychiatric condition. But in the absence of mental health problems, are certain forms of pica, particularly geophagy, abnormal behavior?