Geophagia

Geophagia (pronounced /dʒiəˈfeɪdʒə, -dʒiə/) (also known as geophagy (pronounced /dʒiˈɒfədʒi/)) is the practice of eating earth or soil-like substrates such as clay or chalk. It occurs in non-human animals where it may be a normal or abnormal behaviour, and also in humans, most often in rural or preindustrial societies among children and pregnant women. Human geophagia may be related to pica, an eating disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM) characterized by abnormal cravings for non-nutritive items.

Some researchers believe that humans first ate soil in Africa:

The oldest evidence of geophagia practised by humans comes from the prehistoric site at Kalambo Falls on the border between Zambia and Tanzania (Root-Bernstein & Root-Bernstein, 2000). Here, a calcium-rich white clay was found alongside the bones of Homo habilis (the immediate predecessor of Homo sapiens).

Geophagia is nearly universal around the world in tribal and traditional rural societies (although apparently it has not been documented in Japan and Korea). In the ancient world, several writers noted the use of geophagia. Pliny is said to have noted the use of soil on Lemnos, an island of Greece, and the use of the soils from this island was noted until the 14th century. The textbook of Hippocrates (460–377 BCE) mentions geophagia, and the famous medical textbook called De Medicina edited by A Cornelius Celsus (14–37 CE) seems to link anaemia to geophagia.

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