Geophagy and potential health implications: Geohelminths, microbes and heavy metals

Medical University of Vienna, Center for Public Health, Department of General Practice and Family Medicine, Unit Ethnomedicine and International Health, Waehringerstrasse 25, 1090 Vienna, Austria.
Transactions of the Royal Society of Tropical Medicine and Hygiene (Impact Factor: 1.84). 10/2010; 104(12):787-95. DOI: 10.1016/j.trstmh.2010.09.002
Source: PubMed


The practice of geophagy (soil-eating) is widespread among pregnant and breast-feeding women in sub-Saharan Africa. To assess some of the potential risks accompanying the consumption of geophagic material, we analysed contamination with bacteria, fungi, and geohelminths as well as heavy metals (lead, mercury and cadmium) in 88 African geophagic soil samples, which were purchased in Central, West and East Africa, Europe and the United States. Median microbial viable counts of positive samples were 440 cfu/g (maximum 120,000 cfu/g). The median metal concentrations were 40 mg/kg lead (up to 148 mg/kg), 0.05 mg/kg mercury (up to 0.64 mg/kg), and 0.055 mg/kg cadmium (maximum 0.57 mg/kg). No geohelminth eggs were found in these samples. Our results suggest that geophagic soil samples can be highly contaminated with microbes and may contain high levels of lead. Geophagy, however, is not a cause of adult helminth infection. The periodic consumption of geophagic materials at high dosages might be problematic particularly during pregnancy.


Available from: Claudia Gundacker, Jul 22, 2014
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    • "Indeed, we do not know the exact sources of toxic metals in our population. African geophagic soil samples may contain high levels of lead [55], but in our study the proportions of women reporting geophagy did not differ between preeclamptic women (32 %) and control women (27 %). High blood Pb levels in adults and children from urban Kinshasa have been attributed to leaded gasoline and informal car battery recycling in some residences [56]. "
    [Show abstract] [Hide abstract] ABSTRACT: Background Preeclampsia is frequent in Kinshasa (Democratic Republic of Congo), especially during the dry season. We tested whether preeclampsia was associated with exposure to environmental metals. Methods Using a case-control design, 88 women hospitalized with preeclampsia (cases) and 88 healthy pregnant women from the antenatal clinic (controls) were included in the study; 67 and 109 women were enrolled during the rainy and dry season, respectively. The concentrations of 24 elements were quantified by inductively coupled plasma mass spectrometry (ICP-MS) in 24-h urine collections. Differences in the urinary excretion of metals were investigated between cases and controls, and the interaction with season was assessed. Results Cases and controls were well matched regarding age, parity and duration of pregnancy. In controls, the urinary concentrations of most elements were substantially higher than reference values for adults from industrially developed countries, e.g. for lead: geometric mean (GM) 8.0 μg/L [25th-75th percentile 3.1–13.8]. The daily urinary excretions of 14 metals were significantly higher in women with preeclampsia than in control women, e.g. for lead: GM 61 μg/day (25th–75th percentile 8–345) in women with preeclampsia vs 9 μg/day (25th–75th percentile 3–21) in controls (p < 0 · 001). A significant interaction was found between season and preeclampsia for several elements, with higher urinary excretions in preeclamptic women than controls during the dry season, but not during the rainy season. Conclusions This study revealed not only that women with preeclampsia excrete higher amounts of several toxic metals, especially lead, than control women, but also that this excretion exhibits seasonal variation, thus possibly explaining the high incidence and seasonal variation of preeclampsia in Kinshasa. Although the exact sources of this exposure are unknown, these findings underscore the need for preventing environmental exposures to lead and other toxic metals. Electronic supplementary material The online version of this article (doi:10.1186/s12940-016-0132-1) contains supplementary material, which is available to authorized users.
    Full-text · Article · Dec 2016 · Environmental Health
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    • "Materials present in soil may influence mineral levels in the consumer , while pollutants (industrial and human), parasites and other living organisms may cause disease in humans (Callahan 2003). Several researchers have investigated the heavy metal content, mineralogy and chemistry of African and South African geophagic soils (Ekosse & Jumbam 2010; Kutalek et al. 2010; Ngole et al. 2010). However, a fascinating , yet poorly understood aspect of soil is its microbial component; one which may very well contribute to the possible health risks associated with the practice of geo- phaghia. "
    [Show abstract] [Hide abstract] ABSTRACT: Geopahgia is practiced in many parts of the world and can be associated with medicinal treatments, ceremonial events and spiritual behaviours/practices. This is the first report on a systematic investigation and description of the bacterial diversity in soil regularly ingested by geophagic individuals using a culture-independent method. Diversity in 17 different mining sites was investigated using DGGE. Genetic material from Pantoea, Stenotrophomonas, Listeria, Rhodococcus and Sphingomonads were present in many of the soil samples. Species from these genera are recognized, potential or immerging human pathogens, and are of special interest in immune-compromised individuals. Other genera able to produce a variety of bacteriocins and antimicrobial/antifungal substances inhibitory towards food borne pathogens (Dactylosporangium and Bacillus) and able to degrade a range of environmental pollutants and toxins (Duganella and Massilia) were also present. These essential insights provide the platform for adjusting culturing strategies to isolate specific bacteria, further phylogenetic studies and microbial-mining prospect for bacterial species of possible economic importance.
    Full-text · Article · May 2014 · International Journal of Environmental Health Research
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    • "For example, a cohort study involving 108 pregnant women conducted in Ashanti region of Ghana, reported 54.9% with anemic cases and 17.6% with helminthes infections, of which geophagy, among other factors, was said to be a predisposing factor [17]. In contrast, studies have indicated that geophagy did not increase the risk of helminthes infection, but microbial content was high [2,18]. "
    [Show abstract] [Hide abstract] ABSTRACT: Geophagy, a form of pica, is the deliberate consumption of soil and is relatively common across Sub-Saharan Africa. In Tanzania, pregnant women commonly eat soil sticks sold in the market (pemba), soil from walls of houses, termite mounds, and ground soil (kichuguu). The present study examined geophagy practices of pregnant women in a gold mining area of Geita District in northwestern Tanzania, and also examined the potential for exposure to chemical elements by testing soil samples. We conducted a cross sectional study using a convenience sample of 340 pregnant women, ranging in age from 15-49 years, who attended six government antenatal clinics in the Geita District, Tanzania. Structured interviews were conducted in June-August, 2012, to understand geophagy practices. In addition, soil samples taken from sources identified by pregnant women practicing geophagy were analysed for mineral element content. Geophagy was reported by 155 (45.6%) pregnant women with 85 (54.8%) initiating the practice in the first trimester. A total of 101 (65%) pregnant women reported eating soil 2 to 3 times per day while 20 (13%) ate soil more than 3 times per day. Of 155 pregnant women 107 (69%) bought pemba from local shops, while 48 (31%) consumed ground soil kichuguu. The estimated mean quantity of soil consumed from pemba was 62.5 grams/day. Arsenic, chromium, copper, iron, manganese, nickel and zinc levels were found in both pemba and kichuguu samples. Cadmium and mercury were found only in the kichuguu samples. Based on daily intake estimates, arsenic, copper and manganese for kichuguu and copper and manganese for pemba samples exceed the oral Minimum Risk Levels designated by the U.S. Agency for Toxic Substance and Disease Registry. Almost 50% of participants practiced geophagy in Geita District consistent with other reports from Africa. Both pemba and kichuguu contained chemical elements at varying concentration, mostly above MRLs. As such, pregnant women who eat soil in Geita District are exposed to potentially high levels of chemical elements, depending upon frequency of consumption, daily amount consumed and the source location of soil eaten.
    Full-text · Article · Apr 2014 · BMC Pregnancy and Childbirth
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