Geophagia in Southern Africa: An In-depth Study of the Materials, Benefits and Associated Health Risks

Geophagia is a form of pica that refers specifically to the deliberate ingestion of soils. It was previously reported mainly among pregnant women, but now highly prevalent among unpregnant women and even some men, from all cultures, religions and social groups. It was described by WHO (1996) as a medical condition. Those indulging in the practice have used very interesting reasons to justify the eating of soil. Assumptions associated with geophagy include pregnancy, craving, nutrient supplementation, medicinal value and hunger have been proven and documented in many studies. (Gomes and Silva, 2007; Halsted, 1968; Reilly and Henry, 2001). However, many more reasons including relieving stress, improving female fertility, reducing insomnia, increasing immunity, prevention of STDs, (Songca et al., 2010). remain unsubstantiated. Geophagia is endemic among many communities and despite the negative connotations associated with it, it is not likely to stop.  Considering that the practice of geophagia cannot be eradicated, the main purpose of our research on geophagia has been to make the soils ingested safer for those indulging in the practice. We have characterised soil materials eaten by women in different countries including South Africa, Botswana, Democratic Republic of Congo, Togo Swaziland, Cameroon, and Nigeria in an endeavour to correlate the reasons given to justify the practice with the properties of the soil and to identify properties of the soils ingested that may present a risk to the individuals with a view of  suggesting possible beneficiation processes where necessary. Contrary to people’s belief, our results indicate that

• Soils deliberately ingested are not always clayey in texture and the clay content by weight range between 2% and 11%. The implication of these is that individuals indulging in the practice may suffer from dental enamel destruction since the soil particles are harder that dental enamel. They may also have perorations in the sigmoid colon especially of the soil particles are sharp-edged. Beneficiation processes that would increase the fineness of the soil particles are recommended to reduce the possibility of dental enamel destruction
• Minerals that we identified in geophagic soils include quartz (SiO₂) kaolinite (Al₂Si₂O₅(OH)₄), halite (NaCl), microcline (KAl₃Si₃O₁₀(OH)₂), muscovite (KAlSi₃O₈), goethite (FeO.OH) and/or haematite (Fe₂O₃), siderite (FeCO₃), gibbsite (Al(OH)₃), anatase (TiO₂), talc (Mg₃(OH)₂Si₄O₁₀) and smectite (Na0.3(Al,Mg)₂Si₄O₁₀-(OH)₂.xH₂O) with kaolin being the most dominant secondary mineral in most of the samples studied. be justified by the occurrence of kaolinite in most of the soil samples analysed. The kaolin in the soil is able to absorb moisture from the gastrointestinal tract (GIT) reducing the occurrence of diarrhoea. The use of kaopectate (a kaolin-derived medication) in the treatment of diarrhoea is well documented.  Ingesting kaolin rich soils (like the calabar chalk), could however cause constipation.
• Reduction of salivation and the feeling of nausea during pregnancy is also another reason that women use to justify geophagia. This is related to the electrical conductivity and pH of geophagic soils which are associated with the organoleptic properties of the soils ingested.  Acidic soils have a sour taste whereas soils with high electrical conductivity are salty. These tastes have been reported to contribute to the reduction of salivation and nausea during pregnancy.
• Another health issue associated with geophagia is its potential to contribute to the prevalence of geohelminth (worm) infections. The ova of Ascaris lumbricoides (roundworm), Trichuris trichuria (whipworm), Ancylostoma duodenale (Hookworm) and Strongyloides stercoralis (thread worm) were identified in some samples with A. lumbricoides being the most prevalent. These results indicate that geophagia could be a source of helminth infections among those indulging in the practice Geophagic materials should not be collected from open fields or from topsoil to reduce the intake of helminth ova as a result of geophagia. These results have been presented in Sumbele, Ngole and Ekosse (2014).
• We tested the hypothesis that soils are ingested to supplement for nutrient deficiencies. Our results indicate that the redness of the sil is not directly propotional to the iron content and so using colour alone to determine the Fe content of geophagic soils may therefore be deceitful. Supplementation of iron has been used to justify geophagia but geophagia could in some cases result in anaemia because the minerals contained in the soil as well as the soil CEC would cause the soil to bind Fe in the GIT, reducing its bioaccessibility. This would rather result in Fe absorption from the GIT instead of its supplementation. The consequence will be anaemia.
• Supplementation of Ca among lactating mothers is another assumption made by geopagists. We carried out simulation studies using the physiologically based Extraction technique (PBET). This technique uses gastric juice and pancreatic juice to determine the bioaccessibility of nutrients in materials ingested by humans. With up to 50% bioaccessibility of some supplements (Ca, Co, Cu, Fe, K, Mg, Mn, Na, P and Zn), < 1% of the Recommended dietary allowance (RDA) of a 65kg adult is met by ingesting 30 g of soil daily.

Based on the findings from our different studies, geophagic soils were beneficiated to reduce the associated health risks. The coarse texture was improved through sieving. Geohelminths and other possible pathogens were reduced using UV light and heat treatment. The taste of the soils was improved using mainly salt and sugar in different proportions. These processes resulted in the productions of soils that presented little risks to those ingesting it. The beneficiated soils were mixed with various teas (rooibos, five roses at different proportions) to form an infusion (argillaceous water). The presentation of the soils ingested were modified by packaging them into different shapes (egg shaped, pencil, Cigar) with storage bags.

Acknowledgements

I would like to acknowledge my collaborators namely

• Professor L De Jager (Retired)
• Professor GE Ekosse (University of Venda)
• Professor SP Songca (UKZN)
• Professor B Longo-Mbenza (Retired in DRC)

References.

• De Jager L, Ngole VM and Ekosse GE (2013). Human health aspects related to the ingestion of geophagic clayey soils from the Free State and Limpopo provinces, South Africa. Journal for New Generation Science, 11(2): 1 - 18
• Ekosse G. E. and Ngole VM (2012). Mineralogy, geochemistry and Provenance of geophagic clays from Swaziland. Journal of Applied Clay Science 57; 25 - 31.
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• GE Ekosse, VM Ngole, and B. Longo-Mbenza (2011). Mineralogical and geochemical aspects of geophagic clayey soils from the Democratic Republic of Congo International Journal of Physical sciences 6(31); 7302 – 7313
• GE Ekosse, VM Ngole-Jeme and ML Diko (2017) Environmental Geochemistry of Geophagic Materials from Free State Province in South Africa. Open Geosciences 9(1), 114 – 125.
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• Halsted, J.A., 1968. Geophagia in man: its nature and nutritional effects. The American Journal of Clinical Nutrition 21 (12), 1384–1391.
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By VM Ngole-Jeme
Department of Environmental Sciences, School of Environmental Sciences, College of Agriculture and Environmental Sciences, University of South Africa, Florida 1710,
Roodepoort, Gauteng, South Africa;