Geophagia in rural Mississippi: environmental and cultural contexts and nutritional implications.

We investigated geophagia in the black population of rural Holmes County, Mississippi. Twenty-five sources of geophagical clays were located and most of the sources are associated with rural settlements throughout the county. Clays are taken from subsurface soil horizons, and all but one of the sources come from the upland portion of the county. Geophagia occurs among 57% of women and 16% of children of both sexes, but it is not found among adult males or adolescents. Average daily comsumption of clay is 50 g. Our data indicate geophagia is not correlated with hunger, anemia, or helminthic problems, but it may contribute to the common problem of hypertension. Geophagia has been suggested as one of the factors leading to hyperkalemia, but our data do not support this notion.