BrainStuff Classics: Why Do Some People Eat Dirt?

The craving for and practice of eating earth is more widespread than you might think. Learn why researchers think people engage in this form of pica (i.e., geophagy) in today's classic episode of BrainStuff, based on this article: https://people.howstuffworks.com/culture-traditions/cultural-traditions/why-do-people-eat-dirt.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff.
I'm Lauren vogelbaumb and this is a classic episode of
the podcast. In this one, we dig no pun intended
into the branch of paika called geophagy, that is, the
craving and eating of dirt. It's perhaps surprisingly widespread, though

(00:26):
still not well understood, partially because of sciences biases. Hey
brain Stuff, Lauren Vogel bomb. Here in gas stations and
flea markets all around the southeastern United States, you can
find packets or boxes containing crumbles of white clay. In Kenya,
you can buy reddish dirt on the street, formed into

(00:46):
little pellets that look like baby carrots. In Uganda, you
can buy Yankee Doodle brand dirt at the grocery store.
A website called Earth's Clay Store sells clay from all
over the world and ships them right to your home.
But what are you supposed to do with it when
it gets to you, Well, you eat it. You might
have a vague sense that you've heard of people eating
dirt before pregnant women. Maybe pica is the overarching term

(01:10):
for craving and eating things that are not food. In
the sixth century, ce, the physician Flavius Aecius noticed people
sticking non food items in their mouths the way that
magpies pica in Latin pick up random objects in their beaks.
He figured these people had entirely indiscriminate appetites for just
any old thing, and termed the behavior after the magpie.

(01:31):
It turns out pika is kind of a misnomer because
pika cravings are actually very specific, though according to the
Diagnostic and Statistical Manual of Mental Disorders, or DSM, it
includes a range of behaviors. Some people crave paper clips, batteries,
or coins. These potentially dangerous cravings are considered by the
DSM to be actual disorders, but pica can also include

(01:52):
cravings for a rawstarch that's amylophagy, ice that's pagophagy, and
dirt that's geophagy. Geophogy is one form of pika found
in almost every country in the world. We spoke with
Sarah Young, assistant professor in the Department of Anthropology at
Northwestern University. She said, I was surprised when I first
saw it. I was studying pregnant women ethnography in Zanzibar,

(02:14):
and I asked a woman what she ate when she's pregnant,
and in Swahili, she said, every day, I take earth
from this wall and eat it. I was just learning
Swahili and was pretty good at it, but I really
didn't think I was understanding correctly. My research assistant was like, yeah,
you heard right. Young ended up writing her PhD dissertation
on geopogy and winning the Margaret Meade Award in twenty

(02:35):
thirteen for her book Craving Earth, which detailed her research
about geofogy practices worldwide. In her research, Young tracked down
medical literature, historical texts, research on animal behavior, soil science,
and parasitology, and came to the conclusion that there are
four possible explanations as to why people eat dirt. The
most common and longest running take on geofogy is that

(02:57):
there's no good reason for it, that it's a pathology,
it's an aberrant behavior of some unknown origin. Young explained
the racism, sexism, and classism behind that simplistic take quote
it's the women they know, not what they do explanation.
It was basically white men writing about this for the
past few hundred years, and it was dismissed as aberrant

(03:17):
We can refute this. There are so many species of
animals that go to great risk to get clay in charcoal,
like the colobus monkey that steals charcoal from villagers. But
even so, we know very little about geophagy because for
centuries scientists were stubbornly lacking curiosity about it. When scientists
did start looking into it, the first hypothesis they came

(03:38):
up with to explain why hundreds of thousands of people
worldwide crave and eat dirt is that there must be
something useful in the clay, micronutrients of some kind. Young said,
the mother Nature's multivitamin explanation is a really intuitive one,
but unfortunately it doesn't really shake out for starters. Although
the clay her study participants in Zanzibar were eating was

(03:59):
tinged with red, indicating iron content, investigations into whether that
iron could be absorbed and used by the body came
up empty. Plus. According to Young, people generally prefer whiter clay.
If you give a geophogist to the option of snacking
on Georgia white calin or the reddish clay found on Zanzibar,
they'll almost always pick the white kalin, which does not

(04:19):
contain iron, So we turn to another hypothesis. Could dirt
provide protection from germs. The explanation that eating dirt is
somehow an immune system boost might not make sense on
the surface. After all, we're supposed to stay away from dirt,
wash our hands, clean our clothes, take off our shoes
when we enter the house. But clay face masks can

(04:40):
draw germs and oils and dead cells from your skin
and they're made of dirt, right. According to Young, eating
clay might collect stuff inside of the gut, similar to
how a mud mask collects stuff from your face. But
why would somebody need an intestinal mud mask. The answer
is protection from pathogens and harmful compounds. Many harmful microorganisms

(05:02):
and compounds can enter your body via the things you eat.
You digest the food and it's absorbed through the wall
of your intestine and into your bloodstream. But lots of
potentially harmful stuff can get to us in this way too.
Clay may stimulate the mucous membranes on the surface of
your guts to create more mucus, thus forming a sort
of protective barrier against those pathogens and compounds. Young said.

(05:23):
It can also bind with whatever harmful thing you're eating.
For example, in the Andes, people eat wild potatoes which
contain these toxic chemicals called glycoalkaloids, but after they dip
the potatoes in clay, they become safe to eat. But
while eating clay might protect from pathogens and harmful chemicals,
which is especially important in pregnant women. There's something of

(05:44):
a Goldilocks principle at play here. You want to shield
yourself from the harmful stuff, but you also don't want
to protect yourself from the nutrients you need. For example,
if you eat a steak that's full of both bioavailable
iron and pathogens, but you eat clay at the same time,
the iron could also become bound by the clay and
wouldn't be absorbed by your gut. Although the clay might

(06:04):
be protecting you from pathogens to some extent, it's also
preventing you from absorbing the nutrients. The fourth hypothesis for
why people eat dirt or clay is that it might
help with nausea, vomiting, and diarrhea by coding stomach. After all,
a number of anti diarrheal treatments have kalin in them.
Kalin puts the ko in chaopectate though the reasons for

(06:25):
geophogy are still rather mysterious, Young stresses that it's far
more common than we realize, partially because of those old
stigmas against it. Young said, people don't like to talk
about it or admit it. When I'm doing ethnographic interviews,
I always ask how much earth do you eat? Instead
of do you eat earth? Because so many people have
sworn they don't eat it and later tell me that

(06:45):
they do, but they lied because I didn't want you
to think I was poor. Today's episode is based on
the article why do people eat dirt? On how Stuff
Works Up, written by Jesselyn Shields. Brain Stuff is a
production of iHeartRadio in partnership with how Stuffworks dot Com
and is produced by Tyler clang But four more podcasts

(07:08):
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