1 00:00:01,920 --> 00:00:06,600 Speaker 1: Welcome to brain Stuff production of I Heart Radio, Hey 2 00:00:06,640 --> 00:00:10,160 Speaker 1: brain Stuff Lauren Vogel Bomb. Here in gas stations and 3 00:00:10,200 --> 00:00:13,320 Speaker 1: flea markets all around southeastern United States, you can find 4 00:00:13,360 --> 00:00:17,560 Speaker 1: packets or boxes containing crumbles of white clay. In Kenya, 5 00:00:17,600 --> 00:00:19,880 Speaker 1: you can buy reddish dirt on the street, formed into 6 00:00:19,960 --> 00:00:23,200 Speaker 1: little pellets that look like baby carrots. In Uganda, you 7 00:00:23,239 --> 00:00:25,760 Speaker 1: can buy Yankee Doodle brand dirt at the grocery store. 8 00:00:26,239 --> 00:00:29,040 Speaker 1: A website called Earth's Clay Store sells clay from all 9 00:00:29,040 --> 00:00:30,960 Speaker 1: over the world and ships them right to your home. 10 00:00:31,320 --> 00:00:32,919 Speaker 1: But what are you supposed to do with it when 11 00:00:32,960 --> 00:00:37,080 Speaker 1: it gets to you, Well, you eat it. You might 12 00:00:37,159 --> 00:00:39,360 Speaker 1: have a vague sense that you've heard of people eating 13 00:00:39,400 --> 00:00:43,919 Speaker 1: dirt before pregnant women. Maybe Pika is the overarching term 14 00:00:44,000 --> 00:00:47,000 Speaker 1: for craving and eating things that are not food. In 15 00:00:47,040 --> 00:00:50,600 Speaker 1: the sixth century CE, the physician Flavious Asius noticed people 16 00:00:50,640 --> 00:00:53,000 Speaker 1: sticking non food items in their mouths the way that 17 00:00:53,080 --> 00:00:56,560 Speaker 1: magpies pika in Latin pick up random objects in their beaks. 18 00:00:57,040 --> 00:01:00,400 Speaker 1: He figured these people had entirely indiscriminate app types for 19 00:01:00,480 --> 00:01:03,680 Speaker 1: just any old thing, and termed the behavior after the magpie. 20 00:01:04,600 --> 00:01:07,240 Speaker 1: It turns out pika is kind of a misnomer because 21 00:01:07,280 --> 00:01:10,840 Speaker 1: pike A cravings are actually very specific, though according to 22 00:01:10,880 --> 00:01:13,880 Speaker 1: the Diagnostic and Statistical Manual of Mental Disorders, or d 23 00:01:14,040 --> 00:01:17,360 Speaker 1: s M, it includes a range of behaviors. Some people 24 00:01:17,400 --> 00:01:21,319 Speaker 1: crave paper clips, batteries, or coins. These potentially dangerous cravings 25 00:01:21,319 --> 00:01:24,040 Speaker 1: are considered by the d s M to be actual disorders, 26 00:01:24,360 --> 00:01:27,119 Speaker 1: but pika can also include cravings for raw starch that's 27 00:01:27,120 --> 00:01:33,319 Speaker 1: am allophagy, ice that's patofgy, and dirt that's geophogy. Geofogy 28 00:01:33,319 --> 00:01:35,679 Speaker 1: is one form of pikea found in almost every country 29 00:01:35,760 --> 00:01:39,600 Speaker 1: in the world. We spoke with Sarah Young, assistant professor 30 00:01:39,640 --> 00:01:43,360 Speaker 1: in the Department of Anthropology at Northwestern University. She said, 31 00:01:43,440 --> 00:01:45,319 Speaker 1: I was surprised when I first saw it. I was 32 00:01:45,319 --> 00:01:48,560 Speaker 1: studying pregnant women ethnography in Zanzibar, and I asked a 33 00:01:48,560 --> 00:01:51,400 Speaker 1: woman what she ate when she's pregnant, and in Swahili, 34 00:01:51,520 --> 00:01:53,960 Speaker 1: she said, every day, I take earth from this wall 35 00:01:54,040 --> 00:01:56,640 Speaker 1: and eat it. I was just learning Swaheli and was 36 00:01:56,680 --> 00:01:58,520 Speaker 1: pretty good at it, but I really didn't think I 37 00:01:58,520 --> 00:02:01,760 Speaker 1: was understanding correctly. My research assistant was like, yeah, you 38 00:02:01,840 --> 00:02:06,120 Speaker 1: heard right. Young ended up writing her PhD dissertation on 39 00:02:06,240 --> 00:02:09,680 Speaker 1: geofogy and winning the Margaret Meat Award in for her 40 00:02:09,720 --> 00:02:14,120 Speaker 1: book Craving Earth, which detailed her research about geofogy practices worldwide. 41 00:02:14,880 --> 00:02:18,519 Speaker 1: In her research, Young tracked down medical literature, historical texts, 42 00:02:18,560 --> 00:02:22,359 Speaker 1: research on animal behavior, soil science, in parasitology, and came 43 00:02:22,360 --> 00:02:25,080 Speaker 1: to the conclusion that there are four possible explanations as 44 00:02:25,080 --> 00:02:28,880 Speaker 1: to why people eat dirt. The most common and longest 45 00:02:28,960 --> 00:02:31,440 Speaker 1: running take on geofhogy is that there's no good reason 46 00:02:31,480 --> 00:02:34,440 Speaker 1: for it, that it's a pathology, it's an aberrant behavior 47 00:02:34,480 --> 00:02:39,440 Speaker 1: of some unknown origin. Young explained the racism, sexism, and 48 00:02:39,560 --> 00:02:43,920 Speaker 1: classism behind that simplistic take quote it's the women they know, 49 00:02:44,000 --> 00:02:46,919 Speaker 1: not what they do explanation. It was basically white men 50 00:02:46,960 --> 00:02:49,320 Speaker 1: writing about this for the past few hundred years, and 51 00:02:49,360 --> 00:02:52,320 Speaker 1: it was dismissed as aberrant. We can refute this. There 52 00:02:52,320 --> 00:02:54,520 Speaker 1: are so many species of animals that go to great 53 00:02:54,600 --> 00:02:57,600 Speaker 1: risk to get clay and charcoal, like the colobus monkey 54 00:02:57,639 --> 00:03:01,840 Speaker 1: that steals charcoal from villagers. But even so, we know 55 00:03:02,000 --> 00:03:05,720 Speaker 1: very little about geophogy because for centuries scientists were stubbornly 56 00:03:05,880 --> 00:03:10,240 Speaker 1: lacking curiosity about it. When scientists did start looking into it, 57 00:03:10,440 --> 00:03:12,799 Speaker 1: the first hypothesis they came up with to explain why 58 00:03:12,880 --> 00:03:15,680 Speaker 1: hundreds of thousands of people worldwide crave and eat dirt 59 00:03:16,040 --> 00:03:18,079 Speaker 1: is that there must be something useful in the clay, 60 00:03:18,440 --> 00:03:22,720 Speaker 1: micronutrients of some kind. Young said, the mother Nature's multi 61 00:03:22,800 --> 00:03:27,280 Speaker 1: vitamin explanation is a really intuitive one, but unfortunately it 62 00:03:27,320 --> 00:03:30,560 Speaker 1: doesn't really shake out for starters. Although the clay her 63 00:03:30,600 --> 00:03:33,520 Speaker 1: study participants in Zanzibar were eating was tinged with red, 64 00:03:33,760 --> 00:03:37,640 Speaker 1: indicating iron content, investigations into whether that iron could be 65 00:03:37,680 --> 00:03:41,200 Speaker 1: absorbed and used by the body came up empty. Plus. 66 00:03:41,240 --> 00:03:44,840 Speaker 1: According to Young, people generally prefer whiter clay. If you 67 00:03:44,880 --> 00:03:47,400 Speaker 1: give a geophogist to the option of snacking on Georgia 68 00:03:47,400 --> 00:03:50,400 Speaker 1: white kalin or the reddish clay found on Zanzibar, they'll 69 00:03:50,440 --> 00:03:53,960 Speaker 1: almost always picked the white kalin, which does not contain iron. 70 00:03:55,360 --> 00:03:59,320 Speaker 1: So we turned to another hypothesis. Could dirt provide protection 71 00:03:59,400 --> 00:04:03,000 Speaker 1: from germs. The explanation that eating dirt is somehow an 72 00:04:03,000 --> 00:04:05,880 Speaker 1: immune system boost might not make sense on the surface. 73 00:04:06,160 --> 00:04:08,440 Speaker 1: After all, we're supposed to stay away from dirt, wash 74 00:04:08,520 --> 00:04:10,800 Speaker 1: our hands, clean our clothes, take off our shoes when 75 00:04:10,840 --> 00:04:14,320 Speaker 1: we enter the house. But clay face masks can draw 76 00:04:14,400 --> 00:04:17,040 Speaker 1: germs and oils and dead cells from your skin, and 77 00:04:17,120 --> 00:04:20,680 Speaker 1: they're made of dirt right. According to Young, eating clay 78 00:04:20,760 --> 00:04:23,800 Speaker 1: might collect stuff inside of the gut, similar to how 79 00:04:23,839 --> 00:04:26,960 Speaker 1: a mud mask collects stuff from your face. But why 80 00:04:26,960 --> 00:04:30,440 Speaker 1: would somebody need an intestinal mud mask. The answer is 81 00:04:30,520 --> 00:04:35,680 Speaker 1: protection from pathogens and harmful compounds. Many harmful microorganisms and 82 00:04:35,720 --> 00:04:38,280 Speaker 1: compounds can enter your body via the things you eat. 83 00:04:38,839 --> 00:04:40,960 Speaker 1: You digest the food and it's absorbed through the wall 84 00:04:41,000 --> 00:04:43,919 Speaker 1: of your intestine and into your bloodstream, but lots of 85 00:04:43,960 --> 00:04:47,000 Speaker 1: potentially harmful stuff can get to us in this way too. 86 00:04:47,480 --> 00:04:50,120 Speaker 1: Clay may stimulate the mucus membranes on the surface of 87 00:04:50,160 --> 00:04:52,719 Speaker 1: your guts to create more mucus, thus forming a sort 88 00:04:52,760 --> 00:04:56,920 Speaker 1: of protective barrier against those pathogens and compounds. Young said, 89 00:04:57,240 --> 00:04:59,760 Speaker 1: it can also bind with whatever harmful thing you're eating. 90 00:05:00,240 --> 00:05:03,320 Speaker 1: For example, in the Andes, people eat wild potatoes which 91 00:05:03,320 --> 00:05:07,120 Speaker 1: contain these toxic chemicals called glycoalkaloids, but after they dip 92 00:05:07,160 --> 00:05:11,159 Speaker 1: the potatoes in clay, they become safe to eat. But 93 00:05:11,400 --> 00:05:14,480 Speaker 1: while eating clay might protect from pathogens and harmful chemicals, 94 00:05:14,560 --> 00:05:17,560 Speaker 1: which is especially important in pregnant women, there's something of 95 00:05:17,600 --> 00:05:20,599 Speaker 1: a Goldilocks principle at play here. You want to shield 96 00:05:20,600 --> 00:05:23,000 Speaker 1: yourself from the harmful stuff, but you also don't want 97 00:05:23,000 --> 00:05:26,360 Speaker 1: to protect yourself from the nutrients you need. For example, 98 00:05:26,480 --> 00:05:28,800 Speaker 1: if you eat a steak that's full of both bioavailable 99 00:05:28,839 --> 00:05:32,000 Speaker 1: iron and pathogens, but you eat clay at the same time, 100 00:05:32,360 --> 00:05:34,880 Speaker 1: the iron could also become bound by the clay and 101 00:05:34,920 --> 00:05:37,760 Speaker 1: wouldn't be absorbed by your gut. Although the clay might 102 00:05:37,800 --> 00:05:40,760 Speaker 1: be protecting you from pathogens to some extent, it's also 103 00:05:40,839 --> 00:05:45,120 Speaker 1: preventing you from absorbing the nutrients. The fourth hypothesis for 104 00:05:45,120 --> 00:05:47,400 Speaker 1: why people eat dirt clay is that it might help 105 00:05:47,440 --> 00:05:51,599 Speaker 1: with nausea, vomiting, and diarrhea by coating stomach. After all, 106 00:05:51,680 --> 00:05:54,360 Speaker 1: a number of anti diarreal treatments have kalin in them. 107 00:05:54,720 --> 00:05:59,120 Speaker 1: Kalin puts the KAO in kaopectate. Though the reasons for 108 00:05:59,200 --> 00:06:02,480 Speaker 1: geofogy are still rather mysterious, Young stresses that it's far 109 00:06:02,520 --> 00:06:05,320 Speaker 1: more common than we realize, partially because of those old 110 00:06:05,320 --> 00:06:09,120 Speaker 1: stigmas against it. Young said, people don't like to talk 111 00:06:09,160 --> 00:06:12,120 Speaker 1: about it or admit it. When I'm doing ethnographic interviews, 112 00:06:12,160 --> 00:06:14,880 Speaker 1: I always ask how much Earth do you eat? Instead 113 00:06:14,920 --> 00:06:17,400 Speaker 1: of do you eat earth? Because so many people have 114 00:06:17,480 --> 00:06:19,479 Speaker 1: sworn they don't eat it and later tell me that 115 00:06:19,520 --> 00:06:22,039 Speaker 1: they do. But they lied because I didn't want you 116 00:06:22,080 --> 00:06:29,640 Speaker 1: to think I was poor. Today's episode was written by 117 00:06:29,680 --> 00:06:32,559 Speaker 1: Jesse and Shields and produced by Tyler Clang. Brain Stuff 118 00:06:32,560 --> 00:06:34,920 Speaker 1: is a production of iHeart Radios How Stuff Works. For 119 00:06:35,040 --> 00:06:36,680 Speaker 1: more on this and lots of other food for thought, 120 00:06:36,880 --> 00:06:39,560 Speaker 1: visit our home planet, how stuff Works dot com, and 121 00:06:39,680 --> 00:06:42,039 Speaker 1: for more podcasts for my heart Radio, visit the iHeart 122 00:06:42,120 --> 00:06:44,760 Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your 123 00:06:44,800 --> 00:06:45,440 Speaker 1: favorite shows.