‘A pile of dirt makes me drool’: why some people crave and eat inedible things
Mary (not her real name), a 20-year-old from Ireland, has just quit her habit of eating fire starters. “For most of my adolescence I went through a box of individually wrapped copies every six months,” she says, “but during exam season I went through a box every three weeks. I let the fire starters dry in the box after opening them, because that's what I preferred.”
Mary has pica syndrome (pronounced pike-a), often classified as an eating disorder involving the consumption of non-food items. But even within this state, her version is unusual, leaving her feeling isolated. “I've never heard of anyone else experiencing anything like this,” she says. “Internet searches have led to the poisoning of phone numbers of hotlines or pregnancy forums, as expectant mothers often crave the smell of fire starters. But someone else has to eat them like I used to.”
Pica is the Latin name for the common magpie, which used to have a reputation for flying away with strange things in its beak. The syndrome is probably most common in young children, and then it started nine years ago for Mary, as a means of self-soothing. “I chewed the rubbers of pencils, ate paper and candle wax. These are all common in the pica community,” she says. She always loved the smell of gasoline and would get out of the car to smell it when her parents stopped for gas. That's also why she volunteered to light the fire on winter evenings. When she was 11, after “a very stressful event,” she recalls, “I gave in to the smell of the fire starters I had been sniffing and tasted them.”
It's difficult to say how widespread pica is because it is under-researched and under-reported. Additionally, says Dr. Melinda Karth, a researcher in psychological sciences and eating disorders at Purdue University in Indiana, “there are variations in pica definitions across studies, and a reluctance among adults to admit that they eat 'abnormal things'.” a German study with 2,403 adult participants, published in Epidemiology and Psychiatric Sciences in 2022, found that about 5% reported at least one episode of pica behavior, while 1% said it was recurrent.
“Rates of pica tend to be higher in people with intellectual disability or brain injury compared to people with normal brain function,” says Karth. Pica appears to be most common in young people, but “this may be because adults are reluctant to seek treatment.” When it comes to children, the UK Health Security Agency (UKHSA) says pica is often linked to autism.
Of the things people with pica syndrome eat, Karth says, “pencil points, chalk, plaster of paris, dirt, and ice seem to be the most common,” but what triggers the craving is as mysterious as its prevalence. “It's important to remember that, as with all eating disorders, no two cases are the same, so when people have pica they don't necessarily show the same symptoms.”
Fear can play a role. Some people with pica exhibit obsessive-compulsive behavior, and Karth says, “even though obsessive-compulsivity is no longer considered an anxiety disorder, it is still related to anxiety.” And the impulsiveness or compulsivity that can accompany anxiety plays a major role in other eating disorders, such as binge eating or bulimia nervosa. An important difference from most other eating disorders is that pica is generally “not associated with body dissatisfaction.”
What we do know is that in the rare cases when people seek treatment for pica, selective serotonin reuptake inhibitors (SSRI drugs) that are also prescribed for depression and obsessive compulsive disorder (OCD) “have proven helpful.” With OCD, says Karth, “there is a decrease in serotonin in the brain, which may contribute to the compulsive behavior and impulsivity. So it is possible that pica is also linked to low levels of serotonin in the brain.”
Mineral deficiencies have long been suggested as another possible cause. While some people crave things that are clearly dangerous, like batteries and coins, says Sera L Young, an associate professor of anthropology and global health at Northwestern University in Illinois, “the craving for soil and raw cornstarch appears to have a physiological function that I It would be difficult to call it an eating disorder.” Online pica discussions usually fall into this range, sharing the benefits of different clays, chalks, earths, and even a cornstarch-based baby powder.
“Clay has been used for medicinal treatments for thousands of years,” says Young, “and hundreds of species eat it. When you see Peruvian parrots risking their lives by descending from the canopy to feed on clay licks, or when you see chimpanzees digging for this particular type of clay, you can say, “There's something in this.”
It is thought that birds eat it to help metabolize the toxins in their diet. “Dry powdery substances like clay can bind to the mucin layer of your intestines,” says Young, “creating a barrier to the passage of toxins and pathogens. They can also bind themselves with toxins and pathogens. You can think of it as a mud mask for your intestines.” The problem is that they can also absorb iron, and pica is often linked to anemia, which is what got Young into studying the condition in the first place.
She did fieldwork on anemia during pregnancy off the coast of Tanzania. “Women said, 'When we were pregnant, we started eating dirt.' I thought, 'What?'” She still remembers the moment when, as she sat outside, the women urged her to taste the sunlit earth. “It was very tempting; it dried out your tongue the way the tannins in tea do. But more than just liking it, I was just intrigued.”
Earth eating – known as geophagy – is far from unique to Tanzania. “Many women in high-income countries are also actively looking for the Earth,” says Young. “It is most commonly associated with pregnancy and micronutrient deficiencies, especially in anemia.” That is problematic as it can make the anemia worse. But anyone who loves the earthy taste of new potatoes, or the smell outside when it rains, might have a little insight into the primary appeal of the substance behind the smell. It is probably geosmin, a protein produced by microbes on Earth. Humans are very sensitive to its smell, detecting it at a concentration of 0.1 parts per billion. If you mixed a teaspoon of it into 200 Olympic swimming pools, you would still being able to smell it.
Diane (not her real name), a 26-year-old American, started longing for Earth when she was 22. “It started after I tried a small piece of dried out clay that my younger sister had from pottery school,” she says. say. “I loved the taste of earth – I could taste what felt like the smell of rain on my tongue. I started looking for more.”
People who practice geophagy often talk about their habit as true connoisseurs. Diane ordered herself some so-called “edible clay,” “such as Georgia white clay or kaolin white clay. I usually ordered a pound or two and that lasted for months as I took small bites here and there to satisfy my cravings. For the most part it worked for me, although I didn't really like it as the earthy taste was subtle and the clay stuck to my teeth, which was nothing like the dirt and mud I ate as a child.
When Diane was 24, she found a store on Etsy that sold “exactly the kind of dirt I wanted. It was the excavated dirt instead of the excavated deep clay. I loved it. Almost too much. I ordered 10 pounds every two months for over a year.” Eventually they raised prices, “so I started buying cheap topsoil to sift and eat myself.”
Whether this practice is harmful, Young says, is the million-dollar question. “I think so many things are about dose-response. Sometimes we find lead in the clay, sometimes it is radioactive, sometimes it contains other substances that are not good. While eating a little bit may seem helpful (for some people), eating a lot can go terribly wrong.” When the UKHSA looked at cases of lead poisoning in children last year, it found that 76% of those affected had pica; the exposure consisted mainly of paint or soil.
In Young's research, the behavior often disappears after pregnancy. “I remember very clearly a woman from a longitudinal study in Zanzibar. She said she ate these things, and then I came back a year later and another year later, and she didn't. I said, 'What made you eat this stuff?' And she pointed to her two-year-old sitting on the carpet. She said, 'As soon as he left me, my desire disappeared too.'”
In addition to an air of connoisseurship, people with pica tend to share the language of addiction. Both Mary and Diane say they had to go “cold turkey” to give it up. Diane accomplished this when she was 25. 'I went from eating a few pounds a month to tasting a patch of soil less than once a month. I haven't relapsed yet, but it is very difficult. Just seeing a pile of dirt or an untouched piece of dirt makes me feel hungry. I watch videos of people digging clay or hiking, and seeing the dirt makes me drool. I would really like it to stop.” She suspects she will have to manage hunger for the rest of her life, although blood tests show she is not anemic or lacking important minerals in her diet. “I just love the taste of after rain and I crave it all the time.”
Not that she ever talked to a doctor about her pica. “I decided to turn myself around because I didn't want a time to come where I would have to go to a doctor and then be judged by loved ones again. I don't want to give in to this. It's bad for me and I want to get better.”
Mary says that other than her pica, she doesn't have an addictive personality. “I smoked, but I didn't find it addictive. I drink very small amounts. I have no experience with illegal drugs and could easily not consume my morning coffee,” she says. She hasn't told a doctor either, partly because she's sure her pica will be to blame for her anemia. “It's absolutely possible to eat a balanced diet as a vegetarian,” she says, “but I wasn't getting enough iron or protein in my diet.”
Her abstinence began in August. “I never thought I could do this,” she says. “At first I felt very sick and had overwhelming cravings.” Now she's left with nagging concerns about carcinogens, long-term health effects and relapse. Although she is happy with her progress, she says: “I still find it difficult to walk past the supermarket shelves stocking fire starters, and I would not trust myself to be in an open box for any length of time.”