WEBVTT - Why Do Some People Eat Dirt? 0:00:01.920 --> 0:00:06.600 Welcome to brain Stuff production of I Heart Radio, Hey 0:00:06.640 --> 0:00:10.160 brain Stuff Lauren Vogel Bomb. Here in gas stations and 0:00:10.200 --> 0:00:13.320 flea markets all around southeastern United States, you can find 0:00:13.360 --> 0:00:17.560 packets or boxes containing crumbles of white clay. In Kenya, 0:00:17.600 --> 0:00:19.880 you can buy reddish dirt on the street, formed into 0:00:19.960 --> 0:00:23.200 little pellets that look like baby carrots. In Uganda, you 0:00:23.239 --> 0:00:25.760 can buy Yankee Doodle brand dirt at the grocery store. 0:00:26.239 --> 0:00:29.040 A website called Earth's Clay Store sells clay from all 0:00:29.040 --> 0:00:30.960 over the world and ships them right to your home. 0:00:31.320 --> 0:00:32.919 But what are you supposed to do with it when 0:00:32.960 --> 0:00:37.080 it gets to you, Well, you eat it. You might 0:00:37.159 --> 0:00:39.360 have a vague sense that you've heard of people eating 0:00:39.400 --> 0:00:43.919 dirt before pregnant women. Maybe Pika is the overarching term 0:00:44.000 --> 0:00:47.000 for craving and eating things that are not food. In 0:00:47.040 --> 0:00:50.600 the sixth century CE, the physician Flavious Asius noticed people 0:00:50.640 --> 0:00:53.000 sticking non food items in their mouths the way that 0:00:53.080 --> 0:00:56.560 magpies pika in Latin pick up random objects in their beaks. 0:00:57.040 --> 0:01:00.400 He figured these people had entirely indiscriminate app types for 0:01:00.480 --> 0:01:03.680 just any old thing, and termed the behavior after the magpie. 0:01:04.600 --> 0:01:07.240 It turns out pika is kind of a misnomer because 0:01:07.280 --> 0:01:10.840 pike A cravings are actually very specific, though according to 0:01:10.880 --> 0:01:13.880 the Diagnostic and Statistical Manual of Mental Disorders, or d 0:01:14.040 --> 0:01:17.360 s M, it includes a range of behaviors. Some people 0:01:17.400 --> 0:01:21.319 crave paper clips, batteries, or coins. These potentially dangerous cravings 0:01:21.319 --> 0:01:24.040 are considered by the d s M to be actual disorders, 0:01:24.360 --> 0:01:27.119 but pika can also include cravings for raw starch that's 0:01:27.120 --> 0:01:33.319 am allophagy, ice that's patofgy, and dirt that's geophogy. Geofogy 0:01:33.319 --> 0:01:35.679 is one form of pikea found in almost every country 0:01:35.760 --> 0:01:39.600 in the world. We spoke with Sarah Young, assistant professor 0:01:39.640 --> 0:01:43.360 in the Department of Anthropology at Northwestern University. She said, 0:01:43.440 --> 0:01:45.319 I was surprised when I first saw it. I was 0:01:45.319 --> 0:01:48.560 studying pregnant women ethnography in Zanzibar, and I asked a 0:01:48.560 --> 0:01:51.400 woman what she ate when she's pregnant, and in Swahili, 0:01:51.520 --> 0:01:53.960 she said, every day, I take earth from this wall 0:01:54.040 --> 0:01:56.640 and eat it. I was just learning Swaheli and was 0:01:56.680 --> 0:01:58.520 pretty good at it, but I really didn't think I 0:01:58.520 --> 0:02:01.760 was understanding correctly. My research assistant was like, yeah, you 0:02:01.840 --> 0:02:06.120 heard right. Young ended up writing her PhD dissertation on 0:02:06.240 --> 0:02:09.680 geofogy and winning the Margaret Meat Award in for her 0:02:09.720 --> 0:02:14.120 book Craving Earth, which detailed her research about geofogy practices worldwide. 0:02:14.880 --> 0:02:18.519 In her research, Young tracked down medical literature, historical texts, 0:02:18.560 --> 0:02:22.359 research on animal behavior, soil science, in parasitology, and came 0:02:22.360 --> 0:02:25.080 to the conclusion that there are four possible explanations as 0:02:25.080 --> 0:02:28.880 to why people eat dirt. The most common and longest 0:02:28.960 --> 0:02:31.440 running take on geofhogy is that there's no good reason 0:02:31.480 --> 0:02:34.440 for it, that it's a pathology, it's an aberrant behavior 0:02:34.480 --> 0:02:39.440 of some unknown origin. Young explained the racism, sexism, and 0:02:39.560 --> 0:02:43.920 classism behind that simplistic take quote it's the women they know, 0:02:44.000 --> 0:02:46.919 not what they do explanation. It was basically white men 0:02:46.960 --> 0:02:49.320 writing about this for the past few hundred years, and 0:02:49.360 --> 0:02:52.320 it was dismissed as aberrant. We can refute this. There 0:02:52.320 --> 0:02:54.520 are so many species of animals that go to great 0:02:54.600 --> 0:02:57.600 risk to get clay and charcoal, like the colobus monkey 0:02:57.639 --> 0:03:01.840 that steals charcoal from villagers. But even so, we know 0:03:02.000 --> 0:03:05.720 very little about geophogy because for centuries scientists were stubbornly 0:03:05.880 --> 0:03:10.240 lacking curiosity about it. When scientists did start looking into it, 0:03:10.440 --> 0:03:12.799 the first hypothesis they came up with to explain why 0:03:12.880 --> 0:03:15.680 hundreds of thousands of people worldwide crave and eat dirt 0:03:16.040 --> 0:03:18.079 is that there must be something useful in the clay, 0:03:18.440 --> 0:03:22.720 micronutrients of some kind. Young said, the mother Nature's multi 0:03:22.800 --> 0:03:27.280 vitamin explanation is a really intuitive one, but unfortunately it 0:03:27.320 --> 0:03:30.560 doesn't really shake out for starters. Although the clay her 0:03:30.600 --> 0:03:33.520 study participants in Zanzibar were eating was tinged with red, 0:03:33.760 --> 0:03:37.640 indicating iron content, investigations into whether that iron could be 0:03:37.680 --> 0:03:41.200 absorbed and used by the body came up empty. Plus. 0:03:41.240 --> 0:03:44.840 According to Young, people generally prefer whiter clay. If you 0:03:44.880 --> 0:03:47.400 give a geophogist to the option of snacking on Georgia 0:03:47.400 --> 0:03:50.400 white kalin or the reddish clay found on Zanzibar, they'll 0:03:50.440 --> 0:03:53.960 almost always picked the white kalin, which does not contain iron. 0:03:55.360 --> 0:03:59.320 So we turned to another hypothesis. Could dirt provide protection 0:03:59.400 --> 0:04:03.000 from germs. The explanation that eating dirt is somehow an 0:04:03.000 --> 0:04:05.880 immune system boost might not make sense on the surface. 0:04:06.160 --> 0:04:08.440 After all, we're supposed to stay away from dirt, wash 0:04:08.520 --> 0:04:10.800 our hands, clean our clothes, take off our shoes when 0:04:10.840 --> 0:04:14.320 we enter the house. But clay face masks can draw 0:04:14.400 --> 0:04:17.040 germs and oils and dead cells from your skin, and 0:04:17.120 --> 0:04:20.680 they're made of dirt right. According to Young, eating clay 0:04:20.760 --> 0:04:23.800 might collect stuff inside of the gut, similar to how 0:04:23.839 --> 0:04:26.960 a mud mask collects stuff from your face. But why 0:04:26.960 --> 0:04:30.440 would somebody need an intestinal mud mask. The answer is 0:04:30.520 --> 0:04:35.680 protection from pathogens and harmful compounds. Many harmful microorganisms and 0:04:35.720 --> 0:04:38.280 compounds can enter your body via the things you eat. 0:04:38.839 --> 0:04:40.960 You digest the food and it's absorbed through the wall 0:04:41.000 --> 0:04:43.919 of your intestine and into your bloodstream, but lots of 0:04:43.960 --> 0:04:47.000 potentially harmful stuff can get to us in this way too. 0:04:47.480 --> 0:04:50.120 Clay may stimulate the mucus membranes on the surface of 0:04:50.160 --> 0:04:52.719 your guts to create more mucus, thus forming a sort 0:04:52.760 --> 0:04:56.920 of protective barrier against those pathogens and compounds. Young said, 0:04:57.240 --> 0:04:59.760 it can also bind with whatever harmful thing you're eating. 0:05:00.240 --> 0:05:03.320 For example, in the Andes, people eat wild potatoes which 0:05:03.320 --> 0:05:07.120 contain these toxic chemicals called glycoalkaloids, but after they dip 0:05:07.160 --> 0:05:11.159 the potatoes in clay, they become safe to eat. But 0:05:11.400 --> 0:05:14.480 while eating clay might protect from pathogens and harmful chemicals, 0:05:14.560 --> 0:05:17.560 which is especially important in pregnant women, there's something of 0:05:17.600 --> 0:05:20.599 a Goldilocks principle at play here. You want to shield 0:05:20.600 --> 0:05:23.000 yourself from the harmful stuff, but you also don't want 0:05:23.000 --> 0:05:26.360 to protect yourself from the nutrients you need. For example, 0:05:26.480 --> 0:05:28.800 if you eat a steak that's full of both bioavailable 0:05:28.839 --> 0:05:32.000 iron and pathogens, but you eat clay at the same time, 0:05:32.360 --> 0:05:34.880 the iron could also become bound by the clay and 0:05:34.920 --> 0:05:37.760 wouldn't be absorbed by your gut. Although the clay might 0:05:37.800 --> 0:05:40.760 be protecting you from pathogens to some extent, it's also 0:05:40.839 --> 0:05:45.120 preventing you from absorbing the nutrients. The fourth hypothesis for 0:05:45.120 --> 0:05:47.400 why people eat dirt clay is that it might help 0:05:47.440 --> 0:05:51.599 with nausea, vomiting, and diarrhea by coating stomach. After all, 0:05:51.680 --> 0:05:54.360 a number of anti diarreal treatments have kalin in them. 0:05:54.720 --> 0:05:59.120 Kalin puts the KAO in kaopectate. Though the reasons for 0:05:59.200 --> 0:06:02.480 geofogy are still rather mysterious, Young stresses that it's far 0:06:02.520 --> 0:06:05.320 more common than we realize, partially because of those old 0:06:05.320 --> 0:06:09.120 stigmas against it. Young said, people don't like to talk 0:06:09.160 --> 0:06:12.120 about it or admit it. When I'm doing ethnographic interviews, 0:06:12.160 --> 0:06:14.880 I always ask how much Earth do you eat? Instead 0:06:14.920 --> 0:06:17.400 of do you eat earth? Because so many people have 0:06:17.480 --> 0:06:19.479 sworn they don't eat it and later tell me that 0:06:19.520 --> 0:06:22.039 they do. But they lied because I didn't want you 0:06:22.080 --> 0:06:29.640 to think I was poor. Today's episode was written by 0:06:29.680 --> 0:06:32.559 Jesse and Shields and produced by Tyler Clang. Brain Stuff 0:06:32.560 --> 0:06:34.920 is a production of iHeart Radios How Stuff Works. For 0:06:35.040 --> 0:06:36.680 more on this and lots of other food for thought, 0:06:36.880 --> 0:06:39.560 visit our home planet, how stuff Works dot com, and 0:06:39.680 --> 0:06:42.039 for more podcasts for my heart Radio, visit the iHeart 0:06:42.120 --> 0:06:44.760 Radio app, Apple Podcasts, or wherever you listen to your 0:06:44.800 --> 0:06:45.440 favorite shows.