Some people in the world have a different perception of what’s good to eat and what’s not. For instance, it’s customary to this day in many culture around the globe to eat substances that are considered non-foods in the west, like dirt, clay, sand or raw starches like rice, weird roots and so on.  A recent study, one of the few to dwell in the subject, provides the first population-level data of pica in Madagascar. The findings might be disturbing for some – more than half of the survey community frequently ingest nonfood substances.

Pica is general term describing the craving and intentional consumption of nonfood substances, while amylophagy describes eating raw starches. Both practices have been documented since ancient times, with hundreds of ethnographic descriptions recounting this peculiar behavior among populaces around the world. Currently, biologists have identified some 180 species of animals are also known to engage in pica, possibly to rid themselves of toxins.

A young girl holds vato malemy, a reddish earth found in riverbeds throughout the Makira Protected Area of Madagascar. (c) Christopher Golden

Despite these unusual practices,  neither of the two’s prevalence nor demographic  have been well characterized. With this in mind, an international team of researchers set out to conduct the  first population-level data of pica in Madagascar. They found that of 760 participants from the Makira Protected Area,  63 percent of adult males engaged in pica and amylophagy. Other studies found the behavior abundant in pregnant women and children as well, however the present study found no such evidence, though only four pregnant females were identified. Local taboos against talking about pregnancy prior to birth may have led to underreporting, the authors say.

Across the entire sample in the prior year, 53.4 percent engaged in geophagy, eating specific types of earth, including a fine white clay subsoil, fine sand and red river sediment; 85.2 percent ate such raw starches as raw cassava, raw sweet potato, uncooked rice and another local wild root; and 19 percent ate other items considered locally to be nonfood, including rock salt, used coffee grounds, charcoal, rice chaff, blackboard chalk and ash.

Now, pica has a lot of negative effects, as you might image, but surprisingly enough some positive ones as well. For instance, clay-based pica may be protective, by coating the intestines or binding directly to toxins and pathogens, thereby preventing them from entering the blood, say the researchers. Clay also acts as an anti-diarrhea, a grave issue for people living in Africa, where its one of the biggest killers of children under 5; apparently, pregnant women ingest it frequently. Some believe earth-based pica act like a multivitamin, providing much needed nutrients like  like iron or calcium to the diet, however it’s been found that these are available in too lower quantities to be worth the risks.

E earth, starch or other pica substances could bind to iron in the diet, leading to or worsening anemia. Also, some raw starches are high in calories but are not nutritious. And some substances may contain pathogens or harmful chemicals.

“It could be a really harmful behavior, which causes anemia, for example, or it could be a low-tech protective behavior,” said Sera Young, Ph.D. ’08, a research scientist in the Division of Nutritional Sciences and the paper’s senior author.

Findings were reported in the journal Public Library of Science One.

source: Cornell University.