Geophagy
Encyclopedia
Geophagy is the practice of eating earthy or soil-like substances such as clay
, and chalk
. It exists in animals in the wild and also in humans, most often in rural or preindustrial societies among children and pregnant
women. Human geophagy may be related to pica
, a classified eating disorder in the DSM-IV characterized by abnormal cravings for nonfood items.
, the famous Greek philosopher and physician, was the first to record the use of clay by sick or injured animals back in the second century AD. This type of geophagy has been documented in "many species of mammals, birds, reptiles, butterflies and isopods, especially among herbivores."
Geophagy is well documented in birds. Notably, many species of South American parrots have been observed at clay licks, whilst Sulphur-crested Cockatoo
s have been observed ingesting clays in Papua New Guinea
(Discover, 1998) as well as in Glenbrook in Blue Mountains of Australia
(Parrots Magazine, 2000). Analysis of most soils consumed by wild birds show that they prefer soils with high clay content, often with the smectite and bentonite
clay families being well represented. In vitro and in vivo tests of these soils indicate that they release biologically important quantities of minerals like calcium and sodium, as well as absorbing substantial quantities of small charged compounds such as alkaloids. Because the clays release minerals and absorb other cations as part of the same process of cation exchange, it remains challenging to determine which function is the more important motivator in any given instance of avian geophagy. Separate from soil ingestion, pet birds are often provided with grit which is retained in their gizzard
s to aid in grinding the food they eat.
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).
(a form of geophagy) has been documented in historical sources beginning with Ancient Mesopotamia and Egypt. (Also see under medicinal clay
.)
Geophagy was practised by Native Americans
in California and Peru who would eat earth with acorn
s and potato
es to neutralize potentially harmful alkaloid
s. Clay was used in the production of acorn bread in California and Sardinia, Italy.
women, it is practiced by members of all races, social classes, ages, and sexes. In some parts of the world, geophagia is a culturally sanctioned practice. In many parts of the developing world, earth intended for consumption is available for purchase.
In parts of Africa
, rural areas of the United States, and villages in India, clay consumption is correlated with pregnancy and some women eat clay to eliminate nausea
, possibly because the clay coats the gastrointestinal tract
and may absorb dangerous toxins. The clay may also provide critical calcium
for fetal development
(Vermeer).
In Haiti
, the poorest economy in the Western Hemisphere
, geophagy is widespread. The clay mud is worked into what looks like pancakes or cookies, called "bon bon de terres" (Earthy bon bon
s), that are dried in the sun and sold throughout the poorer areas. Small amounts of other ingredients, vegetable shortening, salt
and sometimes sugar
, are also added to the mix. The cookies have little or no nutritional value
and are associated with various health problems.
While in the US and Europe the practice has often been stigmatized, this is not necessarily so in other parts of the world.
Most non-Western societies consider geophagy to be an adaptive, beneficial, and nutritional approach to promote health.
There is a trend in recent scientific research to study geophagy not as a pathology, but rather as an adaptive behaviour that supplements the diet with essential nutrients or treats a disorder such as diarrhea.
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 a clay, is an active ingredient in many anti-diarrheal medicines.
Edible clay is still available for sale in the American rural South. Clays like activated attapulgite and diosmectite have been used in the active ingredient in over-the-counter antidiarrheal medications. The US version of Kaopectate
, for example, contained kaolinite
clay until a reformulation in 2003.
The Western view of dirt as impure and contaminated may also explain negative connotation and repulsion with geophagy. Geophagy also has a stigma of being an eating habit of African slaves and poor African-Americans. The Victorian
ethic is also amongst the reasons that geophagy became stigmatized in American culture. An ability to control appetite coupled with eating seldom was the appropriate measure of behaviour in a "civilized" Victorian culture, so acting upon a craving for dirt was considered uncivilized because it was seen as having a lack of self-control.
, in that theory, which is a place where diseases are made and spread. Eating the miasma would be viewed as unclean and unhealthy, if not suicidal.
Furthermore, one overarching theme of Western culture is a distancing from the natural world and progress toward technology and efficiency. This movement would render geophagy unacceptable to Westerners. Evidence for this comes from the English language, with phrases like "dirt cheap" and "dirty dog". In non-western cultures, soil is thought of as being a provider for the Earth to grow, and therefore it has nutrients which can be absorbed. It came from a/the god(s) and nourishes the crops which feed the culture. In these cultures, the acceptance is not only seen by secluded tribes, but it is also accepted into the market and into families.
The persistence of geophagy within a family or community can also partially be explained by a simple mother/daughter sharing mechanism. A crucial and sometimes hazardous part of rural communities is the act of giving birth. Without advanced medical knowledge, local customs become key to a healthy outcome. Geophagy enters the picture when daughters would "follow the diet of a woman that they knew had been successful at giving birth".The maternal chain can therefore act as an important vector in the continuance of this act. The practice, in truth, is important because it does provide much needed minerals to the human body. Indeed, Western cultures have continued the practice of geophagy, but only under the guise of vitamins and minerals.
: a Potent Weed Killer is Killing People), it is recommended that a paraquat poisoning victim promptly swallow dirt, even at the risk of salmonella, because paraquat is deactivated upon contact with soil. Otherwise, a sufficiently lethal dose would cause damage to the liver, kidneys, and especially the lungs, usually causing death by asphyxiation by causing severe fibrosis. Lung transplants in two victims merely delayed their deaths because chemical levels still in their bodies subsequently damaged the transplanted lungs, too.
There is also evidence that supports the usefulness of the flora
found in soil. Some have even suggested that it is useful, if not vital, in the establishment of healthy bacteria within the digestive tract, addressing the problems presented by Crohn's Disease
and Leaky Gut Syndrome
. Highly adsorbent families of clays have been demonstrated to cause the lining of the vertebrate gut to change both on a cellular and acellular level, potentially protecting the gut from chemical insults as well as alleviating ailments such as esophagitis, gastritis, and colitis.
Chimpanzee
s 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. Simulated mastication and digestion reveals that the clay helps to release active antimalarial components from the leaves. The same type of soil is used by local healers to treat diarrhea, presumably by the same mechanism as over-the-counter antidiarrheal preparations.
; in particular, parasite eggs, such as roundworm, that can stay dormant for years, can present a problem. Tetanus poses a further risk. Nevertheless, these risks are generally well understood by most tribal populations that engage in geophagy, hence 'clean' earth from below the surface level is sought out. Children's predilection to engage in geophagy makes them more susceptible to worm infestations. Other dangers associated with geophagia include damage to tooth enamel, the ingestion of a variety of bacteria
, various forms of soil contamination, and intestinal obstruction.
In the traditional societies, there is a widespread practice to heat-treat (bake) the earth before consumption, and this tends to mitigate the risks to some extent.
There is a psychological hypothesis, which is centered around the craving ideas, reported by clay eaters. The researchers attention was directed mainly towards the pregnant and postpartum women and their emotional state. Geophagy was attributed to feelings of misery, homesickness, depression, and alienation.
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
, and chalk
Chalk
Chalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates shed from micro-organisms called coccolithophores....
. It exists in animals in the wild and also in humans, most often in rural or preindustrial societies among children and pregnant
Pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
women. Human geophagy may be related to pica
Pica (disorder)
Pica is characterized by an appetite for substances largely non-nutritive . For these actions to be considered pica, they must persist for more than one month at an age where eating such objects is considered developmentally inappropriate...
, a classified eating disorder in the DSM-IV characterized by abnormal cravings for nonfood items.
Animal geophagy
Geophagy is extremely widespread in the animal kingdom. GalenGalen
Aelius Galenus or Claudius Galenus , better known as Galen of Pergamon , was a prominent Roman physician, surgeon and philosopher...
, the famous Greek philosopher and physician, was the first to record the use of clay by sick or injured animals back in the second century AD. This type of geophagy has been documented in "many species of mammals, birds, reptiles, butterflies and isopods, especially among herbivores."
Geophagy is well documented in birds. Notably, many species of South American parrots have been observed at clay licks, whilst Sulphur-crested Cockatoo
Sulphur-crested Cockatoo
The Sulphur-crested Cockatoo, Cacatua galerita, is a relatively large white cockatoo found in wooded habitats in Australia and New Guinea. They can be locally very numerous, leading to them sometimes being considered pests...
s have been observed ingesting clays in Papua New Guinea
Papua New Guinea
Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...
(Discover, 1998) as well as in Glenbrook in Blue Mountains of Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
(Parrots Magazine, 2000). Analysis of most soils consumed by wild birds show that they prefer soils with high clay content, often with the smectite and bentonite
Bentonite
Bentonite is an absorbent aluminium phyllosilicate, essentially impure clay consisting mostly of montmorillonite. There are different types of bentonite, each named after the respective dominant element, such as potassium , sodium , calcium , and aluminum . Experts debate a number of nomenclatorial...
clay families being well represented. In vitro and in vivo tests of these soils indicate that they release biologically important quantities of minerals like calcium and sodium, as well as absorbing substantial quantities of small charged compounds such as alkaloids. Because the clays release minerals and absorb other cations as part of the same process of cation exchange, it remains challenging to determine which function is the more important motivator in any given instance of avian geophagy. Separate from soil ingestion, pet birds are often provided with grit which is retained in their gizzard
Gizzard
The gizzard, also referred to as the ventriculus, gastric mill, and gigerium, is an organ found in the digestive tract of some animals, including birds, reptiles, earthworms and some fish. This specialized stomach constructed of thick, muscular walls is used for grinding up food; often rocks are...
s to aid in grinding the food they eat.
Human geophagy
Considerable evidence exists to indicate that humans practised geophagy from the earliest times.In human prehistory
"The oldest evidence of geophagy practised by humans comes from the prehistoric site at Kalambo FallsKalambo Falls
Kalambo Falls on the Kalambo River is a 772ft single drop waterfall on the border of Zambia and Tanzania at the southeast end of Lake Tanganyika. The falls are some of the tallest uninterrupted falls in Africa...
on the border between Zambia
Zambia
Zambia , officially the Republic of Zambia, is a landlocked country in Southern Africa. The neighbouring countries are the Democratic Republic of the Congo to the north, Tanzania to the north-east, Malawi to the east, Mozambique, Zimbabwe, Botswana and Namibia to the south, and Angola to the west....
and Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...
(Root-Bernstein & Root-Bernstein, 2000)." Here, a calcium-rich white clay was found alongside the bones of Homo habilis
Homo habilis
Homo habilis is a species of the genus Homo, which lived from approximately at the beginning of the Pleistocene period. The discovery and description of this species is credited to both Mary and Louis Leakey, who found fossils in Tanzania, East Africa, between 1962 and 1964. Homo habilis Homo...
(the immediate predecessor of Homo sapiens).
Anthropological and historical evidence
Geophagy is nearly universal around the world in the tribal and traditional rural societies (although apparently it has not been documented in Japan and Korea). Also, the eating of clayClay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
(a form of geophagy) has been documented in historical sources beginning with Ancient Mesopotamia and Egypt. (Also see under medicinal clay
Medicinal clay
The use of medicinal clay in folk medicine goes back to prehistoric times. The indigenous peoples around the world still use clay widely, which is related to geophagy. The first recorded use of medicinal clay goes back to ancient Mesopotamia...
.)
Geophagy was practised by Native Americans
Indigenous peoples of the Americas
The indigenous peoples of the Americas are the pre-Columbian inhabitants of North and South America, their descendants and other ethnic groups who are identified with those peoples. Indigenous peoples are known in Canada as Aboriginal peoples, and in the United States as Native Americans...
in California and Peru who would eat earth with acorn
Acorn
The acorn, or oak nut, is the nut of the oaks and their close relatives . It usually contains a single seed , enclosed in a tough, leathery shell, and borne in a cup-shaped cupule. Acorns vary from 1–6 cm long and 0.8–4 cm broad...
s and potato
Potato
The potato is a starchy, tuberous crop from the perennial Solanum tuberosum of the Solanaceae family . The word potato may refer to the plant itself as well as the edible tuber. In the region of the Andes, there are some other closely related cultivated potato species...
es to neutralize potentially harmful alkaloid
Alkaloid
Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...
s. Clay was used in the production of acorn bread in California and Sardinia, Italy.
Current practice
While geophagy is most often seen in tribal and rural societies among children and pregnantPregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
women, it is practiced by members of all races, social classes, ages, and sexes. In some parts of the world, geophagia is a culturally sanctioned practice. In many parts of the developing world, earth intended for consumption is available for purchase.
In parts of Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, rural areas of the United States, and villages in India, clay consumption is correlated with pregnancy and some women eat clay to eliminate nausea
Nausea
Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...
, possibly because the clay coats the gastrointestinal tract
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
and may absorb dangerous toxins. The clay may also provide critical calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
for fetal development
Fetal development
Prenatal or antenatal development is the process in which a human embryo or fetus gestates during pregnancy, from fertilization until birth. Often, the terms fetal development, foetal development, or embryology are used in a similar sense.After fertilization the embryogenesis starts...
(Vermeer).
In Haiti
Haiti
Haiti , officially the Republic of Haiti , is a Caribbean country. It occupies the western, smaller portion of the island of Hispaniola, in the Greater Antillean archipelago, which it shares with the Dominican Republic. Ayiti was the indigenous Taíno or Amerindian name for the island...
, the poorest economy in the Western Hemisphere
Western Hemisphere
The Western Hemisphere or western hemisphere is mainly used as a geographical term for the half of the Earth that lies west of the Prime Meridian and east of the Antimeridian , the other half being called the Eastern Hemisphere.In this sense, the western hemisphere consists of the western portions...
, geophagy is widespread. The clay mud is worked into what looks like pancakes or cookies, called "bon bon de terres" (Earthy bon bon
Bon Bon
Bonbon refers to any of several types of sweets, especially small candies enrobed in chocolateBon Bon may also refer to:* Bon Bon Reserve, South Australia* Bon-Bon , by Edgar Allan Poe* Bon-Bon Blanco* Bonbon, Grand'Anse...
s), that are dried in the sun and sold throughout the poorer areas. Small amounts of other ingredients, vegetable shortening, salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
and sometimes sugar
Sugar
Sugar is a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose, characterized by a sweet flavor.Sucrose in its refined form primarily comes from sugar cane and sugar beet...
, are also added to the mix. The cookies have little or no nutritional value
Nutrition
Nutrition is the provision, to cells and organisms, of the materials necessary to support life. Many common health problems can be prevented or alleviated with a healthy diet....
and are associated with various health problems.
While in the US and Europe the practice has often been stigmatized, this is not necessarily so in other parts of the world.
Most non-Western societies consider geophagy to be an adaptive, beneficial, and nutritional approach to promote health.
There is a trend in recent scientific research to study geophagy not as a pathology, but rather as an adaptive behaviour that supplements the diet with essential nutrients or treats a disorder such as diarrhea.
Bentonite clay
Bentonite
Bentonite is an absorbent aluminium phyllosilicate, essentially impure clay consisting mostly of montmorillonite. There are different types of bentonite, each named after the respective dominant element, such as potassium , sodium , calcium , and aluminum . Experts debate a number of nomenclatorial...
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 a clay, is an active ingredient in many anti-diarrheal medicines.
Geophagy in the United States
According to "Dixie's Forgotten People: the South's Poor Whites", by J. Wayne Flynt, geophagy was quite common among poor whites in the South-eastern United States. In the 19th and early 20th centuries, this was often ridiculed in popular literature. The literature also states that "Many men believed that eating clay increased sexual prowess, and some females claimed that eating clay helped pregnant women to have an easy delivery." Geophagy being a common practice among southerners may have been caused by the high prevalence of hookworm disease, in which the desire to consume soil is a symptom. Geophagy was common among slaves who were nicknamed "clay-eaters" because they had been known to consume clay, as well as spices, ash, chalk, grass, plaster, paint, and starch. The author cites a recent survey by Obstetrics-Gynecology Clinic at Duke Medical Center in North Carolina, according to which one quarter of patients were clay-eaters.Edible clay is still available for sale in the American rural South. Clays like activated attapulgite and diosmectite have been used in the active ingredient in over-the-counter antidiarrheal medications. The US version of Kaopectate
Kaopectate
Kaopectate, known medically as bismuth subsalicylate, is an orally taken medication from Chattem, Inc. for the treatment of mild diarrhea. It is also sometimes used to treat indigestion, nausea and stomach ulcers...
, for example, contained kaolinite
Kaolinite
Kaolinite is a clay mineral, part of the group of industrial minerals, with the chemical composition Al2Si2O54. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra...
clay until a reformulation in 2003.
The Western view of dirt as impure and contaminated may also explain negative connotation and repulsion with geophagy. Geophagy also has a stigma of being an eating habit of African slaves and poor African-Americans. The Victorian
Victorian era
The Victorian era of British history was the period of Queen Victoria's reign from 20 June 1837 until her death on 22 January 1901. It was a long period of peace, prosperity, refined sensibilities and national self-confidence...
ethic is also amongst the reasons that geophagy became stigmatized in American culture. An ability to control appetite coupled with eating seldom was the appropriate measure of behaviour in a "civilized" Victorian culture, so acting upon a craving for dirt was considered uncivilized because it was seen as having a lack of self-control.
Future
In the past, women who wanted to become pregnant followed the eating patterns of successful mothers instead of changing their diet according to medical studies and recommendations. As a result, geophagy has continued to pass from generation to generation. Cooked, baked, and processed dirt and clay are sold in health food stores and rural flea markets in the South. Researchers have noticed that geophagy is not as prevalent as it once was as rural Americans assimilate into urban culture. In order for geophagy to remain a part of American culture, more effective marketing strategies need to be implemented that fit into modern American culture.Cultural explanations
The cultural meaning of dirt may be another factor that contribute to making geophagy an unacceptable practice in some cultures. Western cultures view dirt as being filthy, especially after the rise of germ theory. Dirt is similar to miasmaMiasma theory of disease
The miasma theory held that diseases such as cholera, chlamydia or the Black Death were caused by a miasma , a noxious form of "bad air"....
, in that theory, which is a place where diseases are made and spread. Eating the miasma would be viewed as unclean and unhealthy, if not suicidal.
Furthermore, one overarching theme of Western culture is a distancing from the natural world and progress toward technology and efficiency. This movement would render geophagy unacceptable to Westerners. Evidence for this comes from the English language, with phrases like "dirt cheap" and "dirty dog". In non-western cultures, soil is thought of as being a provider for the Earth to grow, and therefore it has nutrients which can be absorbed. It came from a/the god(s) and nourishes the crops which feed the culture. In these cultures, the acceptance is not only seen by secluded tribes, but it is also accepted into the market and into families.
The persistence of geophagy within a family or community can also partially be explained by a simple mother/daughter sharing mechanism. A crucial and sometimes hazardous part of rural communities is the act of giving birth. Without advanced medical knowledge, local customs become key to a healthy outcome. Geophagy enters the picture when daughters would "follow the diet of a woman that they knew had been successful at giving birth".The maternal chain can therefore act as an important vector in the continuance of this act. The practice, in truth, is important because it does provide much needed minerals to the human body. Indeed, Western cultures have continued the practice of geophagy, but only under the guise of vitamins and minerals.
Health benefits
In a Science Digest article (ParaquatParaquat
Paraquat is the trade name for N,N′-dimethyl-4,4′-bipyridinium dichloride, one of the most widely used herbicides in the world. Paraquat, a viologen, is quick-acting and non-selective, killing green plant tissue on contact. It is also toxic to human beings and animals...
: a Potent Weed Killer is Killing People), it is recommended that a paraquat poisoning victim promptly swallow dirt, even at the risk of salmonella, because paraquat is deactivated upon contact with soil. Otherwise, a sufficiently lethal dose would cause damage to the liver, kidneys, and especially the lungs, usually causing death by asphyxiation by causing severe fibrosis. Lung transplants in two victims merely delayed their deaths because chemical levels still in their bodies subsequently damaged the transplanted lungs, too.
There is also evidence that supports the usefulness of the flora
Flora
Flora is the plant life occurring in a particular region or time, generally the naturally occurring or indigenous—native plant life. The corresponding term for animals is fauna.-Etymology:...
found in soil. Some have even suggested that it is useful, if not vital, in the establishment of healthy bacteria within the digestive tract, addressing the problems presented by Crohn's Disease
Crohn's disease
Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
and Leaky Gut Syndrome
Leaky gut
Leaky gut is a name used to describe intestinal or bowel hyperpermeability. Tight junctions represent the major barrier within the pathway between intestinal epithelial cells that line the digestion tract...
. Highly adsorbent families of clays have been demonstrated to cause the lining of the vertebrate gut to change both on a cellular and acellular level, potentially protecting the gut from chemical insults as well as alleviating ailments such as esophagitis, gastritis, and colitis.
Chimpanzee
Chimpanzee
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...
s in Kibale National Park
Kibale National Park
Kibale National Park is a national park in South Uganda protecting moist evergreen rain forest. It is 766 km^2 in size and is located between 1100 and 1600 meters in elevation. Despite encompassing primarily moist evergreen forest, it contains a diverse array of landscapes . Kibale is one of the...
, Uganda
Uganda
Uganda , officially the Republic of Uganda, is a landlocked country in East Africa. Uganda is also known as the "Pearl of Africa". It is bordered on the east by Kenya, on the north by South Sudan, on the west by the Democratic Republic of the Congo, on the southwest by Rwanda, and on the south by...
, have been observed to consume soil rich in kaolinite
Kaolinite
Kaolinite is a clay mineral, part of the group of industrial minerals, with the chemical composition Al2Si2O54. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra...
clay shortly before or after consuming plants including Trichilia rubescens, which possesses antimalarial properties in the laboratory. Simulated mastication and digestion reveals that the clay helps to release active antimalarial components from the leaves. The same type of soil is used by local healers to treat diarrhea, presumably by the same mechanism as over-the-counter antidiarrheal preparations.
Health risks
There are obvious risks in the consumption of earth that is contaminated by animal or human fecesFeces
Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...
; in particular, parasite eggs, such as roundworm, that can stay dormant for years, can present a problem. Tetanus poses a further risk. Nevertheless, these risks are generally well understood by most tribal populations that engage in geophagy, hence 'clean' earth from below the surface level is sought out. Children's predilection to engage in geophagy makes them more susceptible to worm infestations. Other dangers associated with geophagia include damage to tooth enamel, the ingestion of a variety of bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, various forms of soil contamination, and intestinal obstruction.
In the traditional societies, there is a widespread practice to heat-treat (bake) the earth before consumption, and this tends to mitigate the risks to some extent.
There is a psychological hypothesis, which is centered around the craving ideas, reported by clay eaters. The researchers attention was directed mainly towards the pregnant and postpartum women and their emotional state. Geophagy was attributed to feelings of misery, homesickness, depression, and alienation.