Geophagia is not associated with parasite transmission in Zanzibar, Tanzania

Abstract

The healthfulness of geophagia, the purposive consumption of earth, is contested. One way in which geophagia may be harmful is as a vector for the transmission of geohelminths. In this study, we pose two questions in a representative sample of 970 pregnant women from Pemba Island, Zanzibar, Tanzania: Is consumed earth a vector for geohelminth infection? Do geophagists have differential parasitic infection? Parasitological analyses were conducted on 42 samples of Pemban soil. Cross‐sectional data about pica behavior was collected through interviews conducted by local researchers. Ascaris, Trichuris and hookworm status was ascertained through Kato‐Katz smears. The prevalence of geophagia in this sample was 5.6%, and overall prevalence of Ascaris, Trichuris and hookworm was 5.6%, 33.2% and 32.9%, respectively. In this study, no consumed soil samples contained infectious parasitic stages. Furthermore, neither the prevalence nor the intensity of infection with Ascaris, Trichuris or hookworm differed significantly by geophagia status. Our results indicate that geophagia is not a source of geohelminth infection among pregnant women in Pemba, which is in contrast to existing findings in other populations. (SLY was supported by NIH training grant 5 T32 HD007331, data collection was supported by the Bill & Melinda Gates Foundation, the Einaudi Center for Intl. Studies, Cornell University, and the Div. of Nutritional Sciences, Cornell University.)

Geophagia clay soil as a source of mineral nutrients and toxicants

“…On the other hand, geophagia has been associated with lead poisoning, hyperkalemia, phosphorous intoxication, dental injury and other undesirable effects including low bone mineralization [7,16]. Several studies have reported associations between geophagia and anaemia, and between geophagia and deficient ferritin levels [1,[17][18][19]. Zinc deficiency has been observed to promote pica in young children [20].…”

“…Despite conflicting views, several evidence point to some nutritional benefits of geophagia. Whereas other researchers have speculated that geophagia during pregnancy may induce iron deficiency anaemia, others have indicated that geophagia may, in fact, be an adaptation to iron deficiency [1,3,18,21]. The high prevalence of geophagia among anaemic pregnant women sparks a quest for knowledge of the potentially available mineral contents of the lithospheric substances ingested.…”