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[BELLS CHIMING] SPEAKER 1: This is a production of Cornell University.
[MUSIC PLAYING]
SPEAKER 2: Welcome to Mann Library's Chats in the Stacks book talk series. In today's talk, originally presented at Mann on November 3, 2011, nutritional scientist Sera Young presents her new book, Craving Earth, on the subject of pica-- the urge to eat clay, starch, ice, and chalk that has been a phenomenon among humans, particularly women, for a very long time. Merging history with intimate case studies, Dr. Young's book offers a rich source of information, helpful to a broad variety of researchers and health practitioners, about a nutritional issue that is still only poorly understood.
[MUSIC PLAYING]
SERA YOUNG: I'd like to start out this talk by saying how fun and gratifying it is to come back to the place that made this book and so much of this research possible. This place meaning Cornell generally. It's a wonderfully multidisciplinary institution. Whoops. And then more specifically, the division of Nutritional Sciences where I received a lot of support. Then most specifically, this library right here. The library systems in particular here just made it happen-- from interlibrary loan, Mann Library, Olin Library. Thank you.
So I'm going to start out by just reading two pages of the book to take you to the moment to when I knew pica was waiting for me. And by the way, you can say "pie-kah" or "pee-kah". It's kind of "to-may-to" "to-mah-to". Europeans tend to say "pee-kah". Americans mispronounce everything so they say "pie-kah". Either way.
"'Every day, twice a day, I take a chunk of earth from this wall and, well, I eat it.' Had I understood Mama Sharifa correctly? We were sitting on a woven palm mat in the only shade in her sun-baked yard on a tiny island called Pemba."
Just to put this in context, so Pemba's in Tanzania, which is in East Africa. And Zanzibar is an archipelago-- it's a group of islands-- but Pemba is the sort of rural backcountry island to a much more touristy and more developed main island called sometimes Zanzibar, sometimes Unguja.
"There were three of us-- Mama Sharifa, Biubwa-- my research assistant-- and me. Our backs were against the dirt wall of her outdoor kitchen, our legs stretched out in front of us discussing the things she eats during pregnancy. With raised eyebrows I look to Biubwa to confirm that I had indeed understood her Swahili. Biubwa nodded. 'Yes, she's saying she eats earth.' 'But why?' I asked.
Mama Sharifa bent at the waist as much as her pregnant belly would allow her to and idly slapped at a fly on her ankle. Then she looked away from us. 'I just eat it, that's all.' Her pink and orange kanga, a light cotton cloth frequently worn as a head covering in East Africa, shifted over her shoulder and obscured her face, and I feared that she would say no more on the matter. But after a long pause her arm reached out from under her kanga.
She turned towards us, plucked a chunk of earth from the highest part of the wall, and displayed it in her open palm." So she was going like this. "I looked from the chunk of her earth in her hand to her face and then back to her hand. I smiled at her and repeated my question. 'But why, Mama?' She was giggling by then out of what I've come to recognize is a combination of embarrassment and sheer inability to answer this question.
She brushed at some dust on her long skirt then stared off into the distance again. And then she locked eyes with me. 'I don't know. I really don't know. I just do it.' She offered the earth to me and I took it. First I smelled it, then I touched it to the tip of my tongue, then I nibbled it into it.
It tasted bland, sort of like old air, but after I swallowed my tongue felt different-- dried out, as if from the astringency of tea that had been brewed for too long. A few grains of sand remained in my mouth long after we had moved on to other topics but for the rest of that research period in Pemba, and for the many that have since followed, I learned as much about earth eating as I could.
I asked pregnant women about their motivations. I quizzed fellow passengers on the public buses. I asked the old men drinking Arabic coffee at dusk. I probed nurses in the antenatal clinics.
What other non-food items do people crave? Did all pregnant women have these cravings? Was it only pregnant women? Did anyone know why they did it? Where did the idea to get these things come from? Is it some sort of religious phenomenon? Which earth is the stuff for eating?
However, my pestering raised only more questions than answers. During another interview that summer the responsibility for understanding pica was unexpectedly shifted to me. I asked Mama Khadija, the second wife of a traditional healer, if she knew why people eat earth." And this is-- you can think of her as my first PhD mentor.
So I asked her why she ate earth. "'I don't know.' 'Do you have any ideas about why some people eat it?' 'No." 'Are you sure?' 'Yes.' 'Not even one?' This time she didn't reply but she just looked at me smiling slightly, shaking her head as one does with an incorrigible child--" like, what are you asking me, basically. [LAUGHS]
"I sheepishly apologized for asking so many questions, but then she said something that changed the trajectory of my academic pursuits. She pointed at my clipboard, and my recorder, and said, 'since you're the researcher, why don't you find out and tell us?' And with that, dear reader, our adventure begins." And what an adventure it has been.
Some of the excitement has been in the field. Any place that I go I ask people about this, but also some of the people in this room have asked people about it-- somebody sitting-- Rebecca Heidkamp got samples for me from Haiti. I mean, the adventures happen outside of Cornell but they also happen here in the libraries. I can't tell you how many thrilling moments I've had of finding the one paragraph in this one volume from 1793 with only two copies of it-- one of which is at the rare manuscript library here. So there's adventures all around.
And I can tell you, I have a lot of references on pica now-- more than 3,000-- and there's all different types of information. So there are individual case studies, like this was from The Lancet in 1884. And one of the fun things about looking at this literature are the titles. Like, we don't make titles like this anymore-- A Remarkable Case of a Juvenile Earth Eater. There are also epidemiological studies, like this is a modern study done in 2005 among pregnant and lactating women in Western Kenya.
And then there are also anthropological reports. And I had to read you this because, like I said, they don't make titles like this anymore. Among Primitive Peoples in Borneo, A Description of the Lives, Habits, and Customs of the Piratical Headhunters-- I didn't know pirate could become an adjective-- of North Borneo, with an Account of Interesting Objects of Prehistoric Antiquity Discovered in the Island. So there's interesting anecdotal culture-level descriptions.
Then there's also a bunch of animal behavior literature like these Amazonian parrots eating earth. So the work that I've done-- I'm not going to talk to you about all the data I've collected. There's been lab stuff, there's been literature, meta-analyses. There's been epidemiological studies. I can assure you, it has yielded all the sort of academic findings that should come from a PhD and that should come from a rigorous study.
But one thing that happened in the course of writing these papers is there was a lot of information that I came across that didn't really belong in an annual review of nutrition paper. I mean, it was fun, and anecdotal, and it's really interesting in a very living kind of behavior. So it just left me with the need to put it all into this book. So I wanted to translate this data and weave into it the sort of more personal anecdotes. And that's what you're going to be hearing today.
If you wanted me to talk really about the data, I'm so happy to do that. But I thought I would keep it light and fun. And so it's going to be a simple talk-- what, who, and why? And I'll start with what.
So what is pica? This is actually Pica pica-- that's the name that Linnaeus gave to this bird. The phenomenon of non-food cravings was given the name pica in the sixth century AD by Aetius of Amida, but the phenomena was written about much earlier than that. So Hippocrates-- who I'm sure you all have heard of-- 400 BC, he wrote, "if a pregnant woman wants to eat earth or charcoal, and eats it, the infant will show signs of these things on its head."
So that's the oldest written evidence, but in fact there's archaeological evidence suggesting that Homo habilis-- so our ancestor from 2 million years ago-- engaged in geophagy. During the question and answer session-- I'm leaving lots of room for it-- you can ask me how we figured out that. But just in case you think it's something that's very old, I'd like to show you a thoroughly modern lady who is also engaging in earth eating.
So you can see, she has beautiful, glittery fingernails, and an exotic front tooth emblem, and she's enjoying white clay. And if any of you get a hankering for it, I do not receive a kickback from this, but there is a website on which you can have earth ordered and delivered discreetly to your house. Yes, I have done that.
And it goes on to say you're not supposed to eat it, it's for-- what do they say? It's something so they don't get sued, but in fact, this is what the purpose is.
So just to say a little bit about the definition of pica because that's been one of the most difficult things with studying it. I define it as a craving and subsequent consumption of items not considered to be food. So accidentally swallowing an eraser-- oops, I was just chewing on my pencil. That's not pica. You're not craving it. But one of the things that really strikes me about pica is how strong the desire is that people have for these non-food substances.
So I'm going to read you just a couple of quotes-- one from a long time ago and one from-- there's a chat room dedicated to talking about these non-food cravings. It's called Cornstarch. It's a Yahoo chat room. So the first one is from India in 1906. "The uncontrollable craving for this earth is like the opium or alcohol habit, and the ravenous symptoms and anxiety in the faces and actions of the eaters are similar to those found in the devotees of one or other of those vices."
OK, so fast forward 105 years and this is a comment from the Yahoo chat room. "I had been two days clean and went over to a friend's house. I had told this friend that I did start cornstarch and was getting off of it. They wanted me to finish the box-- it only had a little in it-- just to see how I do this.
I finished off the starch-- it wasn't much-- and have been craving that taste ever since. I even drove miles out of my way to go to the store they were talking about. It wasn't there." And then in all caps, "man, I want that taste again." So I mean, use it, get off it. The language is of strong cravings.
So there are different types of pica and geophagy is one of them. Also to be pronounced as "gee-off-a-gee". Canadians tend to pronounce it that way. And then there's amylophagy. Amylo comes from starch-- so to eat starch. You can find on YouTube right now videos of women eating starch who are pregnant, just talking about how much they love it.
And I think this next picture is particularly interesting. There's a physician in New York City who was working in Harlem in the '60s-- his name is Gerald Deas-- and he sort of did a one-man campaign to change the labels of Argo Corn Starch. So in the '60s it was sold in the grocery store aisles with like cookies, chips, and corn starch.
People were using it as a snack, especially Black women-- not only when pregnant but especially when pregnant. And it was sold in big chunks because-- this predates me. I only know about spray starch-- but the way you used to starch clothes is to dissolve these chunks in water, dip your clothes in them, let them dry, and then iron them. So it used to be gloss laundry starch sold in chunks.
Women so enjoyed the biting into, the texture, the crunch of that-- and Deas was noticing this-- that he wrote to the company and suggested that "not recommended for food use" appear on the label. That didn't really work. So a few years later, he said to the company, you need to not sell it in chunks. And you can see they responded, now powdered. Mixes more easily. So Argo cornstarch, no longer sold as chunks because of pica.
And then there's pagophagy and that's eating lots of ice. And a lot of people say, oh, I love eating the ice that's in my Coke. At the end of it is, is that pica? No. There are women who go out and buy party bag sizes of ice and eat one of those a day. They've gone through like six pairs of dentures. I mean, people are loving ice. They will organize their whole day around.
Especially-- and I haven't tasted it yet-- Sonic ice. We don't have Sonics here, do we? In New York? But this-- what's that?
AUDIENCE: It's a different texture and shape.
SERA YOUNG: Yeah, exactly, and people love it. This is a screenshot from the Facebook Sonic Ice page last night. 218,000 fans. I mean, if you go to icechewing.com, you can read all of these-- I love ice. Where do you get yours? I love this one. People buy the ice maker that Sonic uses and it's like $1,900. They have to have their whole plumbing redone in their kitchen because they just have this very strong attraction to this food.
But just to clarify, there's non-food cravings and then there's the consumption of these things. Let me make sense of this. In New Mexico, for example, there is a church that's really special because in it it has this grotto-- this place where you can take earth from that has amazing healing properties.
So women and men go and take some bites of this earth and are able to-- this is next to the hole-- to leave their crutches behind, their cancer goes into remission, their sons come back safe from the war, their lovers return. I mean, it's miraculous earth. And that is not craved earth. That is earth that's eaten for religious or sort of spiritual beliefs.
In Bethlehem this is called the Milk Grotto, and according to the legend, Mary stopped off to breastfeed little baby Jesus when they were fleeing from King Herod, who was apparently getting rid of all the under-twos in the kingdom because of a long story behind that, and she spilled a drop of her breast milk, going ahead and turning this whole grotto-- it's called white. But the Earth from this grotto can improve breast milk production, increase fertility, in couples that are infertile fertile.
So that is geophagy-- eating earth from Chimayo in New Mexico or from the Milk Grotto is eating earth but it is not pica. Is that all clear? OK, that's what. But how about who? And in a way I can tell you everywhere-- not everybody, but everywhere.
So one of the things I did was make a database of all the cultural reports of geophagy in the world and what emerged is that it's almost in every country there's been reports of it. And you can think of there's a lot of bias of some countries being studied more than another but almost everywhere it's been reported. So that's where.
But then who? And I can tell you that pica, and especially earth eating, and pregnancy go hand in hand. In so many places husbands are saying-- or I shouldn't say husbands-- baby daddies are saying, I could tell she was pregnant because she was eating earth. Or I knew I was pregnant when I looked at that clay and my mouth started watering. I mean, it's almost a one-to-one relationship.
And we don't have great data on prevalence in every country, but there have been some studies of prevalence, and there are long academic appendices in this book, and you can see it's randomly. Yenza Province, western Kenya, 45% of pregnant women were eating earth. Here's one from Camden, New Jersey. This particular study is fascinating because the interviews were done when women were in active labor.
Now, I mean, I read that before I had gone through active labor and I was like, well, that's sort of a precise time-- no recall bias. But now I'm thinking, what was the IRB thinking? Active labor. Anyway, so 53% of those women were strongly craving ice in their pregnancy. But it's not just humans who do it.
There are caves created in areas of Kenya from elephants digging out particular earth with their tusks. And this is a picture-- in black and white unfortunately-- but this is of a Zanzibari red colobus monkey, and what he has in his mouth isn't clay but it's actually charcoal. So there's an area where charcoal-- and charcoal is manufactured in developing countries-- at least in Tanzania-- where this is like the area where it's made and then you sell it in town.
These monkeys are stealing charcoal from here, and eating it, and fighting over it. When I was describing pica, I talked about the three kinds of major types of pica, but didn't say all of these other substances that people are craving. Like when they can't find clay they'll eat paper, or chalk-- chalkboard chalk-- or charcoal, or ashes, dust, plaster. A lot of it is dry, powdery, absorptive things.
And this is hot off the press. This is some baboons who were recently photographed-- this is like last year. And this woman, bless her, observed like 3,000 hours or something of monkey hours to see who is eating this clay and when. And this is the first time that we know how the different-- like, we would say, oh, elephants eat it or they don't eat it. Or red colobus monkeys eat it or not.
This is the first time we know by life stage who was eating this stuff and I can tell you it's those pregnant baboons who are hitting the clay harder than anyone else. So good job, Paula. And then along the Amazon-- a lot of clay-rich areas are important tourist sites for birdwatchers because parrots, to their great risk-- I mean, they have to come down closer to predators. But there's some benefit to them eating this clay, where they're descending and eating in mass.
So I've talked about what and I've talked about who, but how about why? So there are four explanations. The first one in a way is my favorite because it's so fun to think about. So for a long time geophagy in particular-- but pica in general-- has really just been dismissed. There's no good-- meaning adaptive-- reason. Like no health benefits, no benefits.
There are some other explanations that are more physiological and one of them is hunger. We'll eat this because they don't have anything else to eat. Another is because they have a micronutrient deficiency. So this stuff is acting like a micronutrient, like a supplement. Or to protect against toxins and pathogens. And that's a little bit more complicated to explain but I'll get into it.
So no good or adaptive reason. There's a lot of the people who are eating this are sort of easily dismissed. So women in general-- those women-- what to think-- and then pregnant women especially. I mean, who knows what's going through their mind? So it's easy to say, they're not in their right mind.
There's a whole chapter-- and I think that's one of the more interesting chapters in this book-- talking about some of the other populations who are really commonly engaging in pica and one of those is slaves. African slaves brought either to North America or South America. You can't see it very well here-- this is an etching of a scene in a fancy person's parlor in Brazil, but if you look closely, this person is wearing a mask-- it's a slave who's fanning-- and I'll just read one paragraph describing this practice.
"As curative means, neither promises nor threats-- even when put in execution-- nor yet the confinement of the legs and hands in stocks and manacles exert the least influence. And their preventative"-- over stopping people from eating earth-- "and their preventative effect is temporary, as their employment. So great is the depravity of the appetite and so strongly are the unfortunate sufferers under this complaint subjected to its irresistible dominion.
A metallic mask or mouthpiece secured by a lock is the principal means of security for providing against their indulging in dirt eating if left for a moment to themselves. Nor does this effect a cure or save the life of the patient." It was a horrible abuse meted out onto slaves who were caught eating this stuff and it seemed even not to work. And the idea that the slave owners themselves were thinking that slaves were trying to kill themselves by doing this.
So we have lots of populations with not a lot of political clout in, say, the 1800s when this was really being studied. So it was easy to dismiss. I think we just finished a review for the quarterly review of biology of animal species.
I think we have recorded 284 species of animals who are actively eating earth purposively. So humans might be messed up and do things for weird purposes, but when you look at the other species they can't all be as messed up as humans so there's some adaptive value.
So hunger is another explanation. People are eating this because they don't have anything else to eat. This is just a little bit of data from the study we did in Pemba where we asked people under what circumstances you were you eating earth? And this was actually amylophagy-- uncooked rice in that case. People talked about eating it before food, or with food, or any time, but no one ever ate this stuff because they were hungry.
And there's been in the news, like two or three years ago, that in Haiti people were so hungry they were eating clay. This is a picture of clay disks. Oh, by the way, I should be passing these around. This is a smattering of earth snacks. You're welcome to touch and taste if you'd like.
People were eating this stuff. And as it turns out, they were eating this stuff. They were hungry but the typical use for this clay-- it was called pregnancy clays-- and it was used especially during pregnancy. The micronutrient deficiency question is a really good one because so often pica is associated with especially anemia.
Now I'm delighted to have both Dennis Miller and Gretchen Seim and Cedric-- I thought I saw him here-- in the audience, who is working on some of the cell models to test the bioavailability of this stuff-- of iron in earth samples. I can tell you that what we're seeing right now is some variable iron content. Some samples seem to be kind of high.
And if you look at, for example, this picture on the cover, there's red flecks in the earth, which is a good clue that in fact maybe there's some iron in it. But iron is tightly regulated by the human body, such that bioavailability-- how much we can actually absorb-- is pretty low. More interestingly and more tellingly, a lot of these samples are high in clay.
When you think about clay, like a clay mask-- I'm so beautiful because I use a clay mask to absorb all those impurities in my skin-- clay is really good at filtering like wine and beer, it's good at making babies' diapers more absorptive as a starch. You should be seeing a sort of trend of these substances that people are craving are also absorptive. So there's a lot of clay in these samples.
Which leads to the final functional hypothesis for why people are engaging in geophagy or pica generally, that's that it protects against toxins and pathogens. So Kaopectate-- the kao in Kaopectate comes from kaolin, which is a type of clay. And so the original formulation of this medicine had clay in it and it was a great anti-diarrheal and anti-nausea.
Because of some issues with lead in the clay that was being used, kaolin is no longer in Kaopectate in the United States. It is actually in Canada so if anyone is in Canada and wants to buy me some Kaopectate, I would love that. But right now we can't get kaolin in our American Kaopectate.
And here's a schematic of what we think is happening with these clay-rich substances that people are eating is that it's swallowed, but then what happens is that it binds with the mucin layers in our gut and makes a kind of barrier against harmful pathogens-- like bacteria-- and toxins-- like harmful chemicals in plants.
So when you put this information together what it seems is that this need for protections from pathogens and toxins-- so no one needs more protection than pregnant women, for example-- they need this protection so they are engaging in pica, but this highly absorbent material like clay, starch, charcoal, is binding some of the iron in the diet and therefore causing anemia.
So that's where we are right now. I would like to ask you to please be on the lookout for any pica references. These are two references that I did not find myself, that sleuths in the world sent to me. There is geophagy in The Grapes of Wrath. And then in the New York Times in 2005 there was a story about geophagy in Kyrgyzstan. And so I love receiving pica anecdotes. So by all means, please send them on.
And I would also like to say thank you to many, many people who made this research and this book possible, including the librarians here, the faculty in nutrition and food science, all the people in Pemba who worked very hard, all the people who gave me money to do my research.
And then these two guys who-- one of them did a lot of the programming for some of the data used in this work. And the other one, who gave me the opportunity to see if I would have pica when I was pregnant. [LAUGHS] So thank you very much.
[APPLAUSE]
[BELLS CHIMING]
SPEAKER 1: This has been a production of Cornell University, on the web at cornell.edu.
[BELLS CHIMING]
The urge to eat clay, starch, ice and chalk has been a phenomenon among humans, particularly women, for a very long time. Nutritional scientist Sera Young discussed her new book, "Craving Earth: Understanding Pica--the Urge to Eat Clay, Starch, Ice, and Chalk," November 3, 2011 as part of Mann Library's Chats in the Stacks series.
Dr. Young's research seeks to understand why some people engage in this curious behavior and to shed light on the properties possessed by non-food substances associated with pica.
