Eating earth is surprisingly common. In some countries it is considered an eating disorder, in others it is strongly encouraged. The BBC Future columnist wondered why people want to literally have land?
Sheila grew up in Cameroon, where she first became addicted to kaolin. “I went to elementary school then,” she says. "I often had to buy it for my aunt, who used to eat kaolin." Sheila is currently studying in France.
According to Sheila, for many of her compatriots, this substance is still part of their daily diet. For some, it even develops into a kind of addiction.
Kaolin is not uncommon: it can be bought in almost any market in Cameroon. It is not a prohibited substance or a new drug. This is a local clay rock, land.
Earth-eating, or geophagy, has been common in Cameroon for many years. This phenomenon is detailed in documents from colonial times.
“They say that all [children] eat the earth,” writes the perplexed author of Notes on the Batanga Tribe. "Even the children of missionaries who are unfamiliar with hunger."
According to Sera Young, a geophagy expert at Cornell University (USA), this phenomenon has a very long history in many countries around the world. Young has been studying this behavior for nearly twenty years.
Together with her colleagues, she published a large-scale study that analyzed more than 500 documents from different eras.
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Scientists have concluded that geophagy is widespread throughout the world. Cases of eating land have been reported in Argentina, Iran and Namibia. In addition, the researchers were able to identify several important trends.
First, most of the time people eat land in the tropics. Secondly, the tendency to geophagy is manifested mainly in children (which is probably predictable) and pregnant women.
People eat inedible food more often than you think, and it happens near us.
Sera Young
However, the reason for the lower rates in some countries may be a lack of information due to cultural taboos.
"People eat inedibles more often than you think," Young says, "and it's happening right next to us."
As an example, she cites the story of a famous opera diva from New York, who, during pregnancy, greedily ate the earth, but kept it in a terrible secret.
Young herself became interested in geophagy, collecting material for her research in Tanzania. “I did a survey of local pregnant women about iron deficiency anemia,” she says.
“When I asked one of these women about what she likes to eat during pregnancy, she replied: 'Twice a day I eat earth from the walls of my hut.'
For Young, this came as a big surprise. “It went against everything I was taught,” she says.
Indeed, in Western medicine, geophagy has long been considered a pathology. It is considered a form of perverse eating behavior, along with deliberately eating glass or bleach.
However, in Cameroon, eating land is not associated with any taboos. The situation is the same in Kenya.
Young was surprised to find out that in Kenya you can buy packets of earth with a variety of nutritional supplements, including black pepper and cardamom.
The state of Georgia (USA) produces high quality white clay that can be bought on the Internet. The packages are marked that the product is not intended for human consumption, but everyone knows why they buy it.
The clay instantly absorbs all moisture and adheres to the palate like peanut butter
Young asks if there are African food stores near my home in South London. I answer that there is. “Just go to one of them and ask for clay for pregnant women. She will definitely be there."
Half an hour later I walked out of a store called Products from Africa with a briquette in my hands. I gave 99 pence (about 95 rubles) for it.
I carefully put a piece in my mouth. The clay instantly absorbs all moisture and adheres to the palate like peanut butter. For a second, I can taste smoked meat, but quickly realize that it's just clay, and nothing else.
I wondered why so many people have this addiction.
“Everyone has their own reason,” says Monique, another Cameroonian student. - Someone just wants to, but someone with the help of clay gets rid of nausea and pain in the stomach. Clay is believed to aid digestion."
Is that really true? Maybe geophagy is not a disease, but a method of treatment?
There are three explanations for people eating the earth, and Monique's answer echoes one of them.
Not all earth is the same. Kaolin belongs to a separate group of clay rocks that are most popular among food lovers.
Clay can contain nutrients that are absent in our usual food
Clay has good bonding properties, so Monique's pain relieving effects may be due to its ability to bind or block toxins and pathogens in the digestive system.
Experiments on rats and observation of monkeys have shown that animals can eat inedible substances when poisoned.
In some cuisines around the world, there is a tradition of mixing food with clay to remove toxins and make it more appetizing.
For example, when making acorn bread in California and Sardinia, crushed acorns are mixed with clay to neutralize tannin, which makes them unpleasant.
The second hypothesis is based more on intuition: the clay may contain nutrients that are absent in the food we are used to.
Anemia is often associated with geophagy, so eating iron-rich soil can be explained by an attempt to compensate for iron deficiency.
In addition, there is the assumption that geophagy is a reaction to severe hunger or micronutrient deficiencies, as a result of which something inedible may seem attractive.
It follows that this behavior is maladaptive, that is, eating the earth does not bring any benefit.
On the other hand, according to the first two hypotheses, there are adaptive reasons behind geophagy. This also explains the geographic prevalence of this phenomenon.
“We assumed this was the most common in the tropics, because there is the highest concentration of pathogens,” says Young.
In addition, children and pregnant women may have an increased need for nutrients, as they have weaker immunity.
The wishes of pregnant women are often given too much importance
On the other hand, the desires of pregnant women are often given too much importance.
“Women think they need to be pampered during pregnancy,” says Julia Horms, assistant professor of psychology at the University of Albany (USA).
“There are many myths associated with pregnancy: they say, you need to eat for two and give the fetus everything it needs. But they, as a rule, do not find scientific confirmation."
According to Horms, these desires are largely cultural and have little to do with biology.
If eating land is a cultural tradition, then Cameroonian women will crave it as much as Europeans and Americans crave chocolate or ice cream.
Not everything we want is good for us.
Nevertheless, the desire to eat the earth is found even in those cultures where this is not so important.
Experiments with animals show that this phenomenon can be at least partially explained by adaptive biological reasons.
When elephants, primates, cattle, parrots, and bats eat the land, it is considered normal and even beneficial.
But when it comes to humans, scientists equate this behavior with an eating disorder.
Undoubtedly, in some cases, geophagy is closely related to mental illness, but it is difficult to draw a clear line between illness and norm.
In 2000, the United States Toxic Substances and Disease Registry announced that consuming more than 500 milligrams of earth a day could be considered pathological.
But even the Agency's specialists admitted that this value is conditional.
"Many sources describe geophagy as a cultural phenomenon, and I am not inclined to consider it abnormal behavior," says Ranit Mishori, professor of family medicine and practitioner at Georgetown University Medical Center (USA).
"However, if it is combined with other clinical symptoms, I talk with the patient about how to quit this habit."
Geophagy can also become a habit, impulsive behavior that must be hidden from others.
Eating earth certainly has its downsides. The main concerns are soil borne diseases and clay toxicants.
In addition, there is a possibility that eating clay and earth does not correct micronutrient deficiencies, but rather causes them.
Geophagy can also become a habit, an impulsive behavior that must be hidden from others.
“When describing geophagy, it is sometimes appropriate to use the same terms as in the case of drug addiction,” says Young.
Of course, geophagy can simply be considered a disgusting childhood habit, a quirk of pregnant women, or an exotic addiction of people from distant countries.
But none of these explanations will be one hundred percent correct.
Moreover, such beliefs can lead to the fact that a person prone to geophagy may feel like an outcast because of their "unnatural" desires.
To fully understand this phenomenon and determine what consequences it leads to, it is necessary to test all these hypotheses in practice, taking into account biomedical and cultural factors.
“I'm not saying everyone should eat three tablespoons of earth a day,” Young says. "But that this practice can be harmful remains to be proven."