Speaker 1: Welcome to brain Stuff production of I Heart Radio, Hey
Speaker 1: brain Stuff Lauren Vogel Bomb. Here in gas stations and
Speaker 1: flea markets all around southeastern United States, you can find
Speaker 1: packets or boxes containing crumbles of white clay. In Kenya,
Speaker 1: you can buy reddish dirt on the street, formed into
Speaker 1: little pellets that look like baby carrots. In Uganda, you
Speaker 1: can buy Yankee Doodle brand dirt at the grocery store.
Speaker 1: A website called Earth's Clay Store sells clay from all
Speaker 1: over the world and ships them right to your home.
Speaker 1: But what are you supposed to do with it when
Speaker 1: it gets to you, Well, you eat it. You might
Speaker 1: have a vague sense that you've heard of people eating
Speaker 1: dirt before pregnant women. Maybe Pika is the overarching term
Speaker 1: for craving and eating things that are not food. In
Speaker 1: the sixth century CE, the physician Flavious Asius noticed people
Speaker 1: sticking non food items in their mouths the way that
Speaker 1: magpies pika in Latin pick up random objects in their beaks.
Speaker 1: He figured these people had entirely indiscriminate app types for
Speaker 1: just any old thing, and termed the behavior after the magpie.
Speaker 1: It turns out pika is kind of a misnomer because
Speaker 1: pike A cravings are actually very specific, though according to
Speaker 1: the Diagnostic and Statistical Manual of Mental Disorders, or d
Speaker 1: s M, it includes a range of behaviors. Some people
Speaker 1: crave paper clips, batteries, or coins. These potentially dangerous cravings
Speaker 1: are considered by the d s M to be actual disorders,
Speaker 1: but pika can also include cravings for raw starch that's
Speaker 1: am allophagy, ice that's patofgy, and dirt that's geophogy. Geofogy
Speaker 1: is one form of pikea found in almost every country
Speaker 1: in the world. We spoke with Sarah Young, assistant professor
Speaker 1: in the Department of Anthropology at Northwestern University. She said,
Speaker 1: I was surprised when I first saw it. I was
Speaker 1: studying pregnant women ethnography in Zanzibar, and I asked a
Speaker 1: woman what she ate when she's pregnant, and in Swahili,
Speaker 1: she said, every day, I take earth from this wall
Speaker 1: and eat it. I was just learning Swaheli and was
Speaker 1: pretty good at it, but I really didn't think I
Speaker 1: was understanding correctly. My research assistant was like, yeah, you
Speaker 1: heard right. Young ended up writing her PhD dissertation on
Speaker 1: geofogy and winning the Margaret Meat Award in for her
Speaker 1: book Craving Earth, which detailed her research about geofogy practices worldwide.
Speaker 1: In her research, Young tracked down medical literature, historical texts,
Speaker 1: research on animal behavior, soil science, in parasitology, and came
Speaker 1: to the conclusion that there are four possible explanations as
Speaker 1: to why people eat dirt. The most common and longest
Speaker 1: running take on geofhogy is that there's no good reason
Speaker 1: for it, that it's a pathology, it's an aberrant behavior
Speaker 1: of some unknown origin. Young explained the racism, sexism, and
Speaker 1: classism behind that simplistic take quote it's the women they know,
Speaker 1: not what they do explanation. It was basically white men
Speaker 1: writing about this for the past few hundred years, and
Speaker 1: it was dismissed as aberrant. We can refute this. There
Speaker 1: are so many species of animals that go to great
Speaker 1: risk to get clay and charcoal, like the colobus monkey
Speaker 1: that steals charcoal from villagers. But even so, we know
Speaker 1: very little about geophogy because for centuries scientists were stubbornly
Speaker 1: lacking curiosity about it. When scientists did start looking into it,
Speaker 1: the first hypothesis they came up with to explain why
Speaker 1: hundreds of thousands of people worldwide crave and eat dirt
Speaker 1: is that there must be something useful in the clay,
Speaker 1: micronutrients of some kind. Young said, the mother Nature's multi
Speaker 1: vitamin explanation is a really intuitive one, but unfortunately it
Speaker 1: doesn't really shake out for starters. Although the clay her
Speaker 1: study participants in Zanzibar were eating was tinged with red,
Speaker 1: indicating iron content, investigations into whether that iron could be
Speaker 1: absorbed and used by the body came up empty. Plus.
Speaker 1: According to Young, people generally prefer whiter clay. If you
Speaker 1: give a geophogist to the option of snacking on Georgia
Speaker 1: white kalin or the reddish clay found on Zanzibar, they'll
Speaker 1: almost always picked the white kalin, which does not contain iron.
Speaker 1: So we turned to another hypothesis. Could dirt provide protection
Speaker 1: from germs. The explanation that eating dirt is somehow an
Speaker 1: immune system boost might not make sense on the surface.
Speaker 1: After all, we're supposed to stay away from dirt, wash
Speaker 1: our hands, clean our clothes, take off our shoes when
Speaker 1: we enter the house. But clay face masks can draw
Speaker 1: germs and oils and dead cells from your skin, and
Speaker 1: they're made of dirt right. According to Young, eating clay
Speaker 1: might collect stuff inside of the gut, similar to how
Speaker 1: a mud mask collects stuff from your face. But why
Speaker 1: would somebody need an intestinal mud mask. The answer is
Speaker 1: protection from pathogens and harmful compounds. Many harmful microorganisms and
Speaker 1: compounds can enter your body via the things you eat.
Speaker 1: You digest the food and it's absorbed through the wall
Speaker 1: of your intestine and into your bloodstream, but lots of
Speaker 1: potentially harmful stuff can get to us in this way too.
Speaker 1: Clay may stimulate the mucus membranes on the surface of
Speaker 1: your guts to create more mucus, thus forming a sort
Speaker 1: of protective barrier against those pathogens and compounds. Young said,
Speaker 1: it can also bind with whatever harmful thing you're eating.
Speaker 1: For example, in the Andes, people eat wild potatoes which
Speaker 1: contain these toxic chemicals called glycoalkaloids, but after they dip
Speaker 1: the potatoes in clay, they become safe to eat. But
Speaker 1: while eating clay might protect from pathogens and harmful chemicals,
Speaker 1: which is especially important in pregnant women, there's something of
Speaker 1: a Goldilocks principle at play here. You want to shield
Speaker 1: yourself from the harmful stuff, but you also don't want
Speaker 1: to protect yourself from the nutrients you need. For example,
Speaker 1: if you eat a steak that's full of both bioavailable
Speaker 1: iron and pathogens, but you eat clay at the same time,
Speaker 1: the iron could also become bound by the clay and
Speaker 1: wouldn't be absorbed by your gut. Although the clay might
Speaker 1: be protecting you from pathogens to some extent, it's also
Speaker 1: preventing you from absorbing the nutrients. The fourth hypothesis for
Speaker 1: why people eat dirt clay is that it might help
Speaker 1: with nausea, vomiting, and diarrhea by coating stomach. After all,
Speaker 1: a number of anti diarreal treatments have kalin in them.
Speaker 1: Kalin puts the KAO in kaopectate. Though the reasons for
Speaker 1: geofogy are still rather mysterious, Young stresses that it's far
Speaker 1: more common than we realize, partially because of those old
Speaker 1: stigmas against it. Young said, people don't like to talk
Speaker 1: about it or admit it. When I'm doing ethnographic interviews,
Speaker 1: I always ask how much Earth do you eat? Instead
Speaker 1: of do you eat earth? Because so many people have
Speaker 1: sworn they don't eat it and later tell me that
Speaker 1: they do. But they lied because I didn't want you
Speaker 1: to think I was poor. Today's episode was written by
Speaker 1: Jesse and Shields and produced by Tyler Clang. Brain Stuff
Speaker 1: is a production of iHeart Radios How Stuff Works. For
Speaker 1: more on this and lots of other food for thought,
Speaker 1: visit our home planet, how stuff Works dot com, and
Speaker 1: for more podcasts for my heart Radio, visit the iHeart
Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your
Speaker 1: favorite shows.