Geophagy

Geophagy, literally “earth eating,” also known as pica (technically the consumption of all inappropriate materials), is the practice of consuming dirt, typically clays. Geophagy may be practiced for either health or religious reasons. Devout Christians and Muslims have engaged in ritualized forms of geophagy for centuries, typically in the form of wafers ostensibly derived from holy sites.

Geophagy was widely practiced in many preindustrial societies, particularly in tropical environments and most commonly by pregnant women to relieve the nausea of pregnancy. Through trial-and-error experimentation, many cultures learned to compensate for nutritional deficiencies of trace minerals or vitamins, particularly sulfur, zinc, calcium, phosphorus, potassium, magnesium, and manganese, by consuming certain forms of clay. Consumption of dirt rich in iron is helpful in regions where people suffer from iron deficiency due to the high prevalence of hookworm disease. Soil may be added as well when salt or calcium are deficient in the local diet (especially among non-milk-drinking peoples), or kaolin may be added as an antidiarrheal or gastric disorder treatment, especially for infants. Some Native American tribes, as well as Sardinians, mixed dirt with corn or acorns to neutralize the acids. South American Indians regularly used clays for their alkaloid-binding properties when consuming bitter potatoes. When viewed in this light, geophagy is a rational nutritional adaptation to dire mineral deprivation. However, severe geophagy also carries health risks such as growth retardation and liver enlargement. When it occurs as a regularized social practice, dedicated clay pits and specialized workers are used to harvest, clean, and process the clays consumed, and they may be traded over wide areas. Geophagy is also often prevalent during times of extreme famine.

Although it carries risks of bacterial infection or parasites, in many non-Western cultures, geophagy was culturally sanctioned as healthy and beneficial. Sometimes called “calabash chalk” in much of Africa, clays were consumed by up to half of the population of pregnant or breastfeeding women, either to alleviate morning sickness [Page 1249]or to improve lactation. Geophagy was imported from West Africa to the Southern United States via the institution of slavery. Sometimes known as “Cachexia Africana” in the slave-based South, geophagy among slaves was sometimes prevented through the use of mouth locks.

Despite centuries of attempts to eliminate it and increasingly severe social stigmitization, geophagy persisted in the South. White clay consumption was traditionally confined mostly to impoverished rural black women and children (although some whites too practiced it). A survey in 1942 in Mississippi found that 42% of schoolchildren regularly consumed clays. Sometimes other materials such as starch, chalk, or ash were substituted for clay. Although widely discredited as a practice of poor people (and today, as an eating disorder), in some locales it was institutionalized, and baked or processed clays and dirt are occasionally still found in the South today. Migration from Africa to former colonial countries introduced geophagy into Britain and France.