Geophagia

{{Short description|Practice of eating earth or soil-like substrates}} '''Geophagia''' ({{IPAc-en|ˌ|dʒ|iː|ə|ˈ|f|eɪ|dʒ|(|i|)|ə}}), also known as '''geophagy''' ({{IPAc-en|dʒ|i|ˈ|ɒ|f|ə|dʒ|i}}),<ref>{{Cite journal | author= Ziegler, J.| year=1997 | title=Geophagia: a vestige of paleonutrition?| journal=Tropical Medicine and International Health| volume=2 |issue=7 |pages=609–611 |doi= 10.1046/j.1365-3156.1997.d01-359.x |pmid= 9270727 |s2cid=71822543 |doi-access=free }}</ref> is the intentional<ref>{{cite journal |last1=Fack |first1=Vinciane |last2=Shanee |first2=Sam |last3=Vercauteren Drubbel |first3=Régine |last4=Vercauteren |first4=Martine |last5=Meunier |first5=Hélène |title=Geophagy in the yellow-tailed woolly monkey (Lagothrix flavicauda) at La Esperanza, Peru: site characterization and soil composition |journal=Primates |date=May 2020 |volume=61 |issue=3 |pages=507–518 |doi=10.1007/s10329-020-00802-9 |pmid=32095910 |s2cid=211253699 }}</ref> practice of consuming earth or soil-like substances such as clay, chalk, or termite mounds. It is a behavioural adaptation that occurs in many animals and has been documented in more than 100 primate species.<ref>{{Cite journal | last1=Pebsworth| first1=Paula A.| last2=Huffman| first2=Michael A.| last3=Lambert| first3=Joanna E.| last4=Young| first4=Sera L.| date=January 2019| title=Geophagy among nonhuman primates: A systematic review of current knowledge and suggestions for future directions| journal=American Journal of Physical Anthropology| language=en| volume=168| issue=S67| pages=164–194| doi=10.1002/ajpa.23724| pmid=30508222 | bibcode=2019AJPA..168S.164P| doi-access=free}}</ref> Geophagy in primates is primarily used for protection from parasites, to provide mineral supplements and to help metabolize toxic compounds from leaves.<ref name=":02" /> Geophagy also occurs in humans and is most commonly reported among children and pregnant women.<ref name=":5">{{Cite book|last=Young|first=Sera L.|title=Craving earth : understanding pica: the urge to eat clay, starch, ice, and chalk|publisher=Columbia University Press|year=2011|isbn=978-0-231-14608-1|edition=Pbk.|location=New York|oclc=806349461}}{{pn|date=December 2022}}</ref>

Human geophagia is a form of pica – the craving and purposive consumption of non-food items – and is classified as an eating disorder in the ''Diagnostic and Statistical Manual of Mental Disorders'' (DSM) if not socially or culturally appropriate.<ref>{{Cite book | title=Diagnostic and statistical manual of mental disorders: DSM-5| date=2013| publisher=American Psychiatric Association| author=DSM-5 Task Force| isbn=978-0-89042-554-1| edition=5th| location=Arlington, VA| oclc=830807378}}</ref> Sometimes geophagy is a consequence of carrying a hookworm infection. Although its cause remains unknown, geophagy has many potential adaptive health benefits as well as negative consequences.<ref name=":5" /><ref>{{Cite journal | last1=Young| first1=Sera L.| last2=Miller| first2=Joshua D.| date=February 2019| title=Medicine Beneath Your Feet: A Biocultural Examination of the Risks and Benefits of Geophagy| journal=Clays and Clay Minerals| volume=67| issue=1|pages=81–90| doi=10.1007/s42860-018-0004-6| bibcode=2019CCM....67...81Y|s2cid=132319907}}</ref>

==Animals== {{Further|Zoopharmacognosy}}

Geophagia is widespread in the animal kingdom. Galen, the Greek philosopher and physician, was the first to record the use of clay by sick or injured animals in the second century AD. This type of geophagia has been documented in "many species of mammals, birds, reptiles, butterflies and isopods, especially among herbivores".<ref name="Diamond">{{cite journal|author=Diamond JM|year=1999|title=Evolutionary biology. Dirty eating for healthy living |journal=Nature|volume=400|issue=6740|pages=120–1|bibcode=1999Natur.400..120D|doi=10.1038/22014|pmid=10408435|s2cid=4404459}}</ref>

===Birds=== thumb|upright|Parrots eating earth

Many species of South American parrots have been observed at clay licks, and sulphur-crested cockatoos have been observed ingesting clays in Papua New Guinea. Analysis of soils consumed by wild birds show that they often prefer soils with high clay content, usually with the smectite clay families being well represented.<ref>{{cite journal |last1=Symes |first1=C. T. |last2=Hughes |first2=J. C. |last3=Mack |first3=A. L. |last4=Marsden |first4=S. J. |title=Geophagy in birds of Crater Mountain Wildlife Management Area, Papua New Guinea |journal=Journal of Zoology |date=January 2006 |volume=268 |issue=1 |pages=87–96 |doi=10.1111/j.1469-7998.2005.00002.x }}</ref>

The preference for certain types of clay or soil can lead to unusual feeding behaviour. For example, Peruvian Amazon rainforest parrots congregate not just at one particular bend of the Manu River but at one specific layer of soil which runs hundreds of metres horizontally along that bend. The parrots avoid eating the substrate in layers one metre above or below the preferred layer. These parrots regularly eat seeds and unripe fruits containing alkaloids and other toxins that render the seeds and fruits bitter and even lethal. Because many of these chemicals become positively charged in the acidic stomach, they bind to clay minerals which have negatively charged cation-exchange sites, and are thereby rendered safe. Their preferred soils have a much higher cation-exchange capacity than the adjacent, rejected layers of soils because they are rich in the minerals smectite, kaolin, and mica. The preferred soils surpass the pure mineral kaolinate and surpass or approach pure bentonite in their capacity to bind quinine and tannic acid.<ref name="Diamond" />

''In vitro'' and ''in vivo'' tests of these soils and many others from southeastern Peru indicate that they also release nutritionally important quantities of minerals such as calcium and sodium. In the Manu River example cited above, the preferred soil bands had much higher levels of sodium than those that were not chosen. Repeated studies have shown that the soils consumed most commonly by parrots in South America have higher sodium contents than those that are not consumed.<ref name=":0">{{Cite journal|last1=Emmons|first1=Louise H.|last2=Stark|first2=Nellie M.|date=1979-01-01|title=Elemental Composition of a Natural Mineral Lick in Amazonia|journal=Biotropica|volume=11|issue=4|pages=311–313|doi=10.2307/2387925|jstor=2387925|bibcode=1979Biotr..11..311E }}</ref><ref name=":1">{{Cite journal|last1=Powell|first1=Luke L.|last2=Powell|first2=Thomas U.|last3=Powell|first3=George V. N.|last4=Brightsmith|first4=Donald J.|date=2009-05-01|title=Parrots Take it with a Grain of Salt: Available Sodium Content May Drive Collpa (Clay Lick) Selection in Southeastern Peru|journal=Biotropica |volume=41|issue=3|pages=279–282|doi=10.1111/j.1744-7429.2009.00514.x|s2cid=86506489 |doi-access=free|bibcode=2009Biotr..41..279P }}</ref><ref name=":2">{{Cite journal|last1=Brightsmith|first1=Donald J.|last2=Muñoz-Najar|first2=Romina Aramburú|date=2004-12-01|title=Avian Geophagy and Soil Characteristics in Southeastern Peru|journal=Biotropica |volume=36|issue=4|pages=534–543|doi=10.1111/j.1744-7429.2004.tb00348.x|bibcode=2004Biotr..36..534B |s2cid=85655222 }}</ref>

It is unclear which factor is driving avian geophagy.<ref>{{Cite journal|last1=Brightsmith|first1=Donald J.|last2=Taylor|first2=John|last3=Phillips|first3=Timothy D.|date=2008-11-01|title=The Roles of Soil Characteristics and Toxin Adsorption in Avian Geophagy|journal=Biotropica |volume=40|issue=6|pages=766–774|doi=10.1111/j.1744-7429.2008.00429.x|bibcode=2008Biotr..40..766B |s2cid=83706377 }}</ref> However, evidence is mounting that sodium is the most important driver among parrots in southeastern Peru. Parrots are known to eat toxic foods globally, but geophagy is concentrated in very specific regions.<ref>{{cite journal |last1=Lee |first1=Alan T. K. |last2=Kumar |first2=Sunil |last3=Brightsmith |first3=Donald J. |last4=Marsden |first4=Stuart J. |title=Parrot claylick distribution in South America: do patterns of 'where' help answer the question 'why'? |journal=Ecography |date=June 2010 |volume=33 |issue=3 |pages=503–513 |doi=10.1111/j.1600-0587.2009.05878.x }}</ref> Researchers Lee et{{nbsp}}al. show that parrot geophagy in South America is positively correlated to a significant degree with distance from the ocean. This suggests that overall lack of sodium in the ecosystem, not variation in food toxicity, is a better predictor of the spatial distribution of geophagy. This work, coupled with the recent findings of consistently high sodium levels in consumed soils,<ref name=":0" /><ref name=":1" /><ref name=":2" /> make it highly likely that sodium is the primary driver of avian geophagy among parrots (and possibly other taxa) in the western Amazon Basin. This supplemental nutrients hypothesis is further supported by peak geophagy occurring during the parrots' breeding season.<ref>{{cite journal|author1=Brightsmith, D. J.|author2=Hobson, E. A.|author3=Martinez, G.|year=2018|title=Food availability and breeding season as predictors of geophagy in Amazonian parrots|journal=Ibis|volume=160|issue=1|pages=101–111|doi=10.1111/ibi.12515}}</ref>

===Non-human primates=== [[File:Propithecus candidus ground feeding 001 small.ogv|right|thumb|upright=1|Silky sifaka (''Propithecus candidus'') eating earth]]

There are several hypotheses about the importance of geophagia in bats and primates.<ref name="Abrahams2013">{{cite book|author=Abrahams PW|title=Essentials of Medical Geology|publisher=Springer|year=2013|isbn=978-94-007-4374-8|editor=Selinus O|pages=433–454|chapter=Geophagy and the Involuntary Ingestion of Soil|doi=10.1007/978-94-007-4375-5_18}}</ref>{{rp|436}}<ref name="Krishnamani">{{cite journal |last1=Krishnamani |first1=R. |last2=Mahaney |first2=William C. |title=Geophagy among primates: adaptive significance and ecological consequences |journal=Animal Behaviour |date=May 2000 |volume=59 |issue=5 |pages=899–915 |doi=10.1006/anbe.1999.1376 |pmid=10860518 |s2cid=43702331 }}</ref> Chimpanzees in Kibale National Park, Uganda, have been observed to consume soil rich in kaolinite clay shortly before or after consuming plants including ''Trichilia rubescens'', which possesses antimalarial properties in the laboratory.<ref>{{cite journal|vauthors=Klein N, Fröhlich F, Krief S|year=2008|title=Geophagy: soil consumption enhances the bioactivities of plants eaten by chimpanzees|journal=Naturwissenschaften|volume=95|issue=4|pages=325–31|bibcode=2008NW.....95..325K|doi=10.1007/s00114-007-0333-0|pmid=18188538|s2cid=3181001}}</ref>

thumb|Five Japanese macaques eating soil

Geophagy is a behavioural adaptation seen in 136 species of nonhuman primates from the suborder Haplorrhini (81%) and Strepsirrhini (19%).<ref name=":12">{{Cite journal |last1=Pebsworth |first1=Paula A. |last2=Huffman |first2=Michael A. |last3=Lambert |first3=Joanna E. |last4=Young |first4=Sera L. |date=January 2019 |title=Geophagy among nonhuman primates: A systematic review of current knowledge and suggestions for future directions |journal=American Journal of Physical Anthropology |language=en |volume=168 |issue=S67 |pages=164–194 |doi=10.1002/ajpa.23724 |pmid=30508222 |bibcode=2019AJPA..168S.164P |s2cid=54568458 |doi-access=free }}</ref> The most commonly ingested soils are soils from mounds, soils from tree bases, soils from termite mounds, 'Pong' soils, and forest floor.<ref name=":02">{{Cite journal |date=2000-05-01 |title=Geophagy among primates: adaptive significance and ecological consequences |journal=Animal Behaviour |language=en |volume=59 |issue=5 |pages=899–915 |doi=10.1006/anbe.1999.1376 |last1=Krishnamani |first1=R. |last2=Mahaney |first2=William C. |pmid=10860518 |s2cid=43702331 }}</ref> Studies have shown many benefits of geophagy such as protection from parasites (4.9%), mineral supplements (19.5%), and helping to metabolize toxic compounds from leaves (12.2%) nonexclusive.<ref name=":02" /> From soil analysis, it has been seen that one of the main compounds in the earth consumed by these primates is clay minerals that contains kaolinite, which is commonly used in medications for diarrheal and intestinal problems.<ref name=":22">{{Cite journal |last=Knezevich |first=Mary |date=1998 |title=Geophagy as a therapeutic mediator of endoparasitism in a free-ranging group of rhesus macaques (Macaca mulatta) |journal=American Journal of Primatology |volume=44 |issue=1 |pages=71–82 |doi=10.1002/(sici)1098-2345(1998)44:1<71::aid-ajp6>3.0.co;2-u |pmid=9444324 |s2cid=29283286 }}</ref> Geophagic behaviour plays an important role in nonhuman primates' health.<ref name=":02" /> This kind of zoopharmacognosy use differs from one species to another. For example, mountain gorillas from Rwanda tend to ingest clay soil during dry season, when the vegetation changes forcing them to feed on plants that have more toxic compounds, in this case the ingested clay absorbs these toxins providing digestive benefits.<ref name=":02" /> This kind of seasonal behavioural adaptation is also seen in the red-handed howler monkeys from the western Brazilian Amazonia, which also have to adapt to the shift of feeding on leaves that contains more toxic compounds.<ref>{{cite journal |last1=de Souza |first1=Luciane L. |last2=Ferrari |first2=Stephen F. |last3=da Costa |first3=Marcondes L. |last4=Kern |first4=Dirse C. |title=Geophagy as a Correlate of Folivory in Red-Handed Howler Monkeys (Alouatta belzebul) from Eastern Brazilian Amazonia |journal=Journal of Chemical Ecology |date=2002 |volume=28 |issue=8 |pages=1613–1621 |id={{ProQuest|733005062}} |doi=10.1023/A:1019928529879 |pmid=12371813 |bibcode=2002JCEco..28.1613D |s2cid=1025743 }}</ref> In other cases, geophagy is used by the Ring-Tailed Lemurs as a preventive and therapeutic behaviour for parasite control and intestinal infection.<ref name=":12" /> These benefits from clay ingestion can also be observed among rhesus macaques.<ref name=":22" /> In a study that was carried out in the island of Cayo Santiago, it has been observed that the rhesus macaques had intestinal parasites and their health was not affected and they did not have many gastrointestinal effects from these parasites.<ref name=":22" /> Data observed shows that this was caused by the consumption of clay soil by this species.<ref name=":22" /> On the other hand observations have shown that behavioural geophagy provides mineral supplements, as seen among Cambodia's Colobinae.<ref name=":32">{{cite journal |first1=Benjamin M. |last1=Rawson |first2=Luu Tuong |last2=Bach |title=Preliminary observations of geophagy amongst Cambodia's Colobinae |journal=Vietnamese Journal of Primatology |volume=1 |issue=5 |date=September 2011 |pages=41–46 |url=http://static1.1.sqspcdn.com/static/f/1200343/26921539/1458250826810/Vietnamese_J_Primatol_Vol_1-5_2011.pdf?token=RyE8ppozE4kCpDKwXcXh5YrkQF4%3D#page=43 }}</ref> The study was done at the salt licks in Veun Sai-Siem Pang Conservation Area, a site that is visited by various species of nonhuman primates.<ref name=":32" /> More in-depth research needs to be carried out in order to better understand this behavioural adaptation of geophagy among nonhuman primates.

===Bats=== There is debate over whether geophagia in bats is primarily for nutritional supplementation or detoxification. It is known that some species of bats regularly visit mineral or salt licks to increase mineral consumption. However, Voigt et{{nbsp}}al. demonstrated that both mineral-deficient and healthy bats visit salt licks at the same rate.<ref name="Voigt">{{cite journal|vauthors=Voigt CC, Capps KA, Dechmann DK, Michener RH, Kunz TH|date=2008|title=Nutrition or Detoxification: Why Bats Visit Mineral Licks of the Amazonian Rainforest|journal=PLOS ONE|volume=3|issue=4|article-number=e2011|bibcode=2008PLoSO...3.2011V|doi=10.1371/journal.pone.0002011|pmc=2292638|pmid=18431492|doi-access=free}}</ref> Therefore, mineral supplementation is unlikely to be the primary reason for geophagia in bats. Additionally, bat presence at salt licks increases during periods of high energy demand.<ref name="Voigt" /> Voigt et{{nbsp}}al. concluded that the primary purpose for bat presence at salt licks is for detoxification purposes, compensating for the increased consumption of toxic fruit and seeds.<ref name="Voigt" />

=== Livestock === The hooves of livestock such as cattle and sheep collect soil and press it against vegetation of pastures on which they graze, causing ingestion for soil. It can be observed as a function of ash content in the feces. This is common especially in weak, poorly drained soils, which easily break apart. In autumn and winter, wetter conditions render soil muddier and hence more transferrable. Other factors are the density of livestock grazing and the consumption of earthworm casts. In sheep, soil consumption can also cause cumulative incisor tooth wear. Since the soil contains various nutrients such as iron, manganese, zinc, cobalt, copper, selenium, and iodine that herbage lacks, it contributes to nutrition of grazers.<ref>{{Cite book |title=McGraw-Hill encyclopedia of science & technology |date=2012 |publisher=McGraw-Hill |isbn=978-0-07-179273-8 |edition=11th |volume=8 |location=New York, NY |pages=66}}</ref>

==Humans==

===Anthropological and historical evidence=== Evidence for the likely origin of geophagy was found in the remains of early humans in Africa:

{{blockquote|text=The oldest evidence of geophagy 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'').| sign=Peter Abrahams| source=''Geophagy and the Involuntary Ingestion of Soil''<ref name=Abrahams2013/>{{rp|446}} }}

thumb|right|upright=1|A five-year-old girl in Peru with a desire to eat earth (geophagia). Wood engraving by E. Riou, 1860s.

Geophagia is nearly universal around the world in tribal and traditional rural societies (although apparently it has not been documented in Japan or Korea).<ref name=Abrahams2013 /> In the ancient world, several writers noted the phenomenon of geophagia. Pliny is said to have noted the ingestion of soil on Lemnos, an island of Greece, and the use of the soils from this island was noted until the 14th century.<ref name=Abrahams2013 /><ref name="Woywodt">{{cite journal | last1=Woywodt, A|last2=Kiss, A| title=Geophagia: the history of earth-eating| journal=Journal of the Royal Society of Medicine| date=2002| volume=95| issue=3| pages=143–6| pmid=11872770| doi=10.1177/014107680209500313| pmc=1279487}}</ref> The textbook of Hippocrates (460–377 BCE) mentions geophagia, and the famous medical textbook titled ''De Medicina'' edited by A.{{nbsp}}Cornelius Celsus (14–37 CE) seems to link anaemia to geophagia.<ref name="Woywodt" /> One of Rumi's fables tells about a geophage being cheated by a sugar seller who leaves him alone with a weight made of clay and then waits until the man eats enough of it, thus reducing the amount of sugar he will get.<ref>{{cite web | url=http://www.masnavi.net/3/25/eng/4/624/ | title=Rumi's Masnavi - when those looks have drawn thee after me, then thou wilt know that I am not inattentive to thee. }}</ref>

The existence of geophagy among Native Americans was noted by early explorers in the Americas, including Gabriel Soares de Sousa, who in 1587 reported a tribe in Brazil using it in suicide,<ref name=Abrahams2013 /> and Alexander von Humboldt, who said that a tribe called the Otomacs ate large amounts of soil.<ref name="Woywodt" /> In Africa, David Livingstone wrote about slaves eating soil in Zanzibar,<ref name="Woywodt" /> and it is also thought that large numbers of slaves brought with them soil-eating practices when they were trafficked to the New World as part of the transatlantic slave trade.<ref name=Abrahams2013 /> Slaves who practised geophagia were nicknamed "clay-eaters" because they were known to consume clay, as well as spices, ash, chalk, grass, plaster, paint, and starch.<ref name=HenryKwong/>

===Contemporary practices=== right|thumb|upright=1|Several different rocks of clay-like material being sold at a local market in Kabwe, Zambia. These are usually purchased and consumed by pregnant women.

In Africa, kaolinite, sometimes known as ''kalaba'' (in Gabon<ref>Karine Boucher, Suzanne Lafage. [http://www.unice.fr/ILF-CNRS/ofcaf/14/K14.html "Le lexique français du Gabon: K."] ''Le Français en Afrique: Revue du Réseau des Observatoires du Français Contemporain en Afrique''. 2000.</ref> and Cameroon),<ref name="Balengou">Franklin Kamtche. [http://www.quotidienlejour.com/double-page-/reportage/504-balengou-autour-des-mines "Balengou : autour des mines."] {{webarchive | url=https://web.archive.org/web/20120304025224/http://www.quotidienlejour.com/double-page-/reportage/504-balengou-autour-des-mines| date=March 4, 2012}} (Balengou: around the mines) ''Le Jour''. 12 January 2010. {{in lang|fr}}</ref> ''calaba'', and ''calabachop'' (in Equatorial Guinea), is eaten for pleasure or to suppress hunger.<ref name="Balengou"/> Kaolin for human consumption is sold at most markets in Cameroon and is often flavoured with spices such as black pepper and cardamom.<ref>{{cite news | url=http://www.bbc.com/future/story/20160615-the-people-who-cant-stop-eating-dirt| title=The people who can't stop eating dirt| work=BBC News| date=16 June 2016}}</ref> Consumption is greatest among women, especially to cure nausea during pregnancy, in spite of the possible dangerous levels of arsenic and lead to the unborn child.<ref name="Callahan">{{cite journal | author=Callahan GN |title=Eating dirt |journal=Emerging Infect. Dis. |volume=9 |issue=8 |pages=1016–21 |year=2003 |pmid=12971372 |pmc=3020602 |doi=10.3201/eid0908.ad0908|doi-broken-date=2025-07-12 }}</ref><ref name=":4">{{Cite news | date=2008-09-18| title=Why Kenyan women crave stones| language=en-GB| url=https://news.bbc.co.uk/2/hi/7596067.stm| access-date=2019-03-16}}</ref> Another example of geophagia was reported in Mangaung, Free State Province in South Africa, where the practice was geochemically investigated.<ref name=":3" /> Calabash chalk is also eaten in west Africa.<ref>{{Cite journal |last1=Madziva |first1=Cathrine |last2=Chinouya |first2=Martha Judith |date=2020 |title=Clay Ingestion During Pregnancy Among Black African Women in a North London Borough: Understanding Cultural Meanings, Integrating Indigenous and Biomedical Knowledge Systems |journal=Frontiers in Sociology |volume=5 |article-number=20 |doi=10.3389/fsoc.2020.00020 |issn=2297-7775 |pmc=8022624 |pmid=33869429 |doi-access=free }}</ref>

[[File:Haitian Dirt Biscuits.jpg|thumb|right|upright=1|Haitian mud cookies being prepared]]

In Haiti, poor people are known to eat bonbon tè made from soil, salt, and vegetable shortening. These biscuits hold minimal nutritional value, but manage to keep the poor alive.<ref>{{cite news | url=http://www.huffingtonpost.com/2009/02/19/dirt-poor-haitians-eat-mu_n_168339.html |title=Dirt Poor Haitians Eat Mud Cookies To Survive |editor1=Schmidt, Benno |editor2=Ayer, Ara |date=22 March 2009 |newspaper=Huffington Post |access-date=9 August 2015}}</ref> However, long-term consumption of the biscuits is reported to cause stomach pains and malnutrition, and is not recommended by doctors.<ref>{{cite web | title= Poor Haitians Resort to Eating Dirt| url=http://news.nationalgeographic.com/news/2008/01/080130-AP-haiti-eatin.html| archive-url=https://web.archive.org/web/20100214194356/http://news.nationalgeographic.com/news/2008/01/080130-AP-haiti-eatin.html| archive-date=14 February 2010|author=Jonathan M. Katz | publisher=National Geographic| access-date=2015-03-21}}</ref>

Some Southern African American communities consume kaolin as a supplement and traditional medicine, particularly for pregnant women.<ref>{{Cite journal |last=Vermeer |first=DE |last2=Frate |first2=DA |date=1979-10-01 |title=Geophagia in rural Mississippi: environmental and cultural contexts and nutritional implications |url=https://www.sciencedirect.com/science/article/pii/S0002916523289777 |journal=The American Journal of Clinical Nutrition |volume=32 |issue=10 |pages=2129–2135 |doi=10.1093/ajcn/32.10.2129 |issn=0002-9165|url-access=subscription }}</ref> The practice was reportedly declining by 1984<ref>{{Cite news |last=Schmidt |first=William |date=February 13, 1984 |title=Southern Practice of Eating Dirt Shows Signs of Waninf |url=https://www.nytimes.com/1984/02/13/us/southern-practice-of-eating-dirt-shows-signs-of-waning.html |url-status=live |work=New York Times}}</ref> but has continued In some communities well into the 21st century.<ref>{{Cite web |last=Rude |first=Emelyn |date=2015-06-05 |title=The American South Is Still Eating White Dirt |url=https://www.vice.com/en/article/the-american-south-is-still-eating-white-dirt/ |access-date=2026-01-19 |website=VICE |language=en-US}}</ref>

In Central Java and East Java, Indonesia a food made of soil called ampo is eaten as a snack or light meal.<ref name=Indo>{{in lang|id}} Ampo, Camilan dari Tanah Liat. [http://www.indosiar.com/fokus/ampo-camilan-dari-tanah-liat_62015.html indosiar.com] {{webarchive |url=https://web.archive.org/web/20140831194318/http://www.indosiar.com/fokus/ampo-camilan-dari-tanah-liat_62015.html |date=August 31, 2014 }}</ref><ref name=H>Ampo, Snack Made By Soil. Do You Believe It? [http://ipku.tk/R hubpages.com]{{Dead link|date=May 2019 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref name=fla>Think twice before you say ew {{usurped|1=[https://web.archive.org/web/20100906203106/http://www.flavorboulevard.com/think-twice-before-you-say-ew/ 2013 Flavor Boulevard ]}}</ref> It consists of pure clay, without any mixture of ingredients.<ref name=Indo />

Bentonite clay is available worldwide as a digestive aid; kaolin is also widely used as a digestive aid and as the base for some medicines. Attapulgite, another type of clay, is an active ingredient in many anti-diarrheal medicines.<ref name="HenryKwong">{{cite journal | doi= 10.1080/713840222 | vauthors=Henry J, Kwong AM |pages=353–71 |title=Why is geophagy treated like dirt? | journal= Deviant Behavior |volume= 24 |issue= 4 |year= 2003|s2cid=144401343 }}</ref>

=== Impact on health === [[File:Ascaris infection in X-ray image- Pica, the practice of eating soil (South Africa) (16424840111).jpg|thumb|right|upright=1|Silica in the soil that has been eaten by a woman shows up as white on this plain X-ray]]

Clay minerals have been reported to have beneficial microbiological effects, such as protecting the stomach against toxins, parasites, and pathogens.<ref>{{cite journal |vauthors=Williams LB, Haydel SE |title=Evaluation of the medicinal use of clay minerals as antibacterial agents |journal= International Geology Review|volume=52 |issue=7/8 |pages=745–70 |year=2010 |pmid=20640226 |pmc=2904249 |doi=10.1080/00206811003679737 |bibcode=2010IGRv...52..745W }}</ref><ref name="Lallanilla">{{cite web |url=https://abcnews.go.com/Health/Diet/story?id=1167623&page=1&singlePage=true |title=Eating Dirt: It Might Be Good for You |editor=Lallanilla, Marc |date=3 October 2005 |work=ABC News |access-date=9 August 2015}}</ref> Humans are not able to synthesize vitamin B12 (cobalamin), so geophagia may be a behavioral adaptation to obtain it from bacteria in the soil.<ref>{{cite book |vauthors=Henry JM, Cring FD |date=2012 |chapter= Geophagy An Anthropological Perspective |veditors=Brevik EC, Burgess LC |title= Soils and Human Health |pages=179–198 |publisher= CRC Press |doi=10.1201/b13683-12 |isbn=978-1-4398-4454-0|s2cid=239518574 }}</ref> Mineral content in soils may vary by region, but many contain high levels of calcium, copper, magnesium, iron, and zinc; these minerals are critical for developing fetuses, which may explain cravings by pregnant women to chew metallic objects, soil, ice cravings. Pregnant women may also experience ice-chewing cravings or drives towards specifically cold food to trigger vasoconstricting, which increases brain oxygen levels by restricting neck veins; both cravings, soil and ice, may have familial and environmental links. Multigenerationally-impoverished villages and other homogenous, socioeconomically-closed genetic communities are more likely to have rewarded gene expression of soil or clay consumption, because such cravings increased the likelihood of survival through multiple pregnancies for both sexes.<ref name="Lallanilla"/><ref>{{cite web |url=https://www.sciencedaily.com/releases/2011/06/110602162820.htm |title=Eating dirt can be good for the belly, researchers find |editor=University of Chicago Press Journals |date=4 June 2011 |publisher=ScienceDaily |access-date=9 August 2015}}</ref>

There are obvious health risks in the consumption of soil that is contaminated by animal or human feces; in particular, helminth eggs, such as ''Ascaris'', which can stay viable in the soil for years, can lead to helminth infections.<ref name="obi">{{cite journal |vauthors=Bisi-Johnson MA, Obi CL, Ekosse GE |title= Microbiological and health related perspectives of geophagia: an overview |journal= African Journal of Biotechnology |volume=9 |issue= 36 |pages=5784–91|date= 2010 |url= http://www.ajol.info/index.php/ajb/article/download/92778/82208}}</ref><ref>{{cite book |doi=10.1016/B978-0-7020-5101-2.00056-X |chapter=Soil-transmitted Helminths (Geohelminths) |title=Manson's Tropical Infectious Diseases |year=2014 |last1=Brooker |first1=Simon J. |last2=Bundy |first2=Donald A.P. |pages=766–794.e4 |isbn=978-0-7020-5101-2 }}</ref> Tetanus poses a further risk.<ref name=obi /> Lead poisoning is also associated with soil ingestion,<ref>{{cite book |doi=10.1016/B978-0-444-52272-6.00158-6 |chapter=Human Health and the State of the Pedosphere |title=Encyclopedia of Environmental Health |year=2011 |last1=Cook |first1=A. |last2=Ljung |first2=K. |last3=Watkins |first3=R. |pages=108–115 |isbn=978-0-444-52272-6 }}</ref> as well as health risks associated with zinc exposure can be problematic among people who eat soils on a regular basis.<ref name=":3">{{Cite journal |last1=Ekosse |first1=Georges-Ivo E. |last2=Ngole-Jeme |first2=Veronica M. |last3=Diko |first3=Makia L. |date=2017-05-25 |title=Environmental Geochemistry of Geophagic Materials from Free State Province in South Africa |journal=Open Geosciences |volume=9 |issue=1 |page=9 |doi=10.1515/geo-2017-0009 |bibcode=2017OGeo....9....9E |doi-access=free}}</ref> Gestational geophagia (geophagia in pregnancy) has been associated with various homeostatic disruptions and oxidative damage in rats.<ref>{{cite journal |last1=Agomuo |first1=EN |last2=Amadi |first2=PU |last3=Adumekwe |first3=C |title=Gestational Geophagia Affects Nephrocardiac Integrity, ATP-Driven Proton Pumps, the Renin-Angiotensin-Aldosterone System, and F2-Isoprostane Status. |journal= Medical Sciences |date=22 January 2019 |volume=7 |issue=2 |doi=10.3390/medsci7020013 |pmid=30678242 |pmc=6409520 |page=13|doi-access=free }}</ref>

==See also== * Medicinal clay, a variety of clays chosen and used for medicinal purposes, including through consumption. *Lithophagy, ingestion of stones

==References== {{Reflist}}

==Further reading== *{{Cite journal|author=Cooper, D. W.|year=2000 |title=Clay Eating Parrots |journal=Parrots Magazine |volume= 36}} *{{Cite book | contribution = Geophagy | title = Encyclopedia of Food and Culture | editor-last = Katz | editor-first = Solomon H. | last = Wiley | first = Andrea S. | volume = 2 | pages = 120–121 | place = New York | publisher = Charles Scribner's Sons | year = 2003 }}

==External links== * [https://stacks.cdc.gov/view/cdc/14230 "Eating Dirt"] at the CDC

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{{DEFAULTSORT:Geophagia}} Category: Geophagia