Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
21 Jul

Eating Earth: Exploring the Mysterious World of Geophagy

clayA few weeks ago I got into an unusual conversation with a guy in a coffee shop. We were both passing through town – he for personal travel and me for business. We struck up a conversation waiting in line and ended up chatting for the remainder of our respective stops there. We talked about what we did, where we were headed, etc. When I mentioned the blog and the PB philosophy behind it, his face lit up. He loved the idea and had embraced similar principles several years prior. His latest experiment, the health effects of which he raved about, was adding dirt to his diet. I listened with interest and asked questions.

You all know I’m big on dirt, and more specifically, on probiotic supplementation. And while I’ve touched on the health benefits of dirt, the immune building properties of dirt consumption in children, and the connection between dirt and clinical depression in youngsters, I’ve never met anyone who made a personal habit of dirt ingestion. I’d heard of the practice in traditional societies, but it had always been one of those concepts I’d thought about in passing and tabled for another time. The idea has been on my mind ever since that exchange.

On the one hand, how more fundamental can it get than ingesting earth – the very source of sustenance (in one way or another)? There’s minerals, probiotics, and all manner of goodies to be had. On the other hand – lest we forget the more savage side of ecology – there are the less hospitable microbes, the more insidious creepy crawlies – (roundworm, anyone?). Though my conversation partner that day explained with pride and assurance that he obtained his dietary dirt from only the most trusted, meticulous, and local purveyor, I wondered if I could get past the Fear Factor element. He seemed so taken by its effects – the weight loss, the improved digestion, the higher energy. With some careful caveats, could it be worth eating dirt?

In truth, humans have been eating earth for as long as we’ve been around – and not just because Grok didn’t have a salad spinner. Geophagy has been observed throughout the world – everywhere from sub-Saharan Africa to Europe, Asia to Australia. In the U.S., geophagy has figured into the culture of various indigenous cultures and to the past (and present) of the South, where experts believe native Africans who were brought as slaves introduced the practice.

It’s not just one of collective humanity’s hobby horses either. Scientists have studied geophagy in a host of other mammals as well, including elephants, wolves, and primates. Surely, this common a practice must have some kind of adaptive element?

A recent article from Lapham’s Quarterly traced the unusual, circuitous, and sometimes unsettling practice of geophagy in human history. (Those of you who count among your passions both history and food will appreciate the publication’s summer issue.) From a scientific angle, our understanding of geophagy has involved its crucial distinction from pica, the consumption of all varieties of non-edibles like coins, hair, soap, etc. Our view has also been colored by the interplay of cultures, the character of terrain and its vegetation, and the division between scientific and traditional approaches to health.

The article traces at length the career of Alexander Humboldt, an 18th and 19th century explorer, who first noted geophagy in the native population of a South American mission he visited. The indigenous Otomacs, Humboldt noted, ate a “‘prodigious quantity’” of “‘soft, unctuous clay” (which they called poya) that they obtained from particular areas of a nearby river bank. In fact, they not only ate it but meticulously collected it for routine seasonal storage. Humboldt was both floored and disgusted. Nonetheless, he was apparently hooked from then on. In the proceeding decades, he continued to study geophagy as it was observed around the world. His research “normalized” geophagy to the extent that people learned to associate it less with abnormal psychology and more with long-standing tradition across the globe, even in regions as “civilized” as Sweden and Finland.

Fast forward a couple centuries, and we’re still digging for the physiological roots of geophagy – the why. The who is pretty clear. Experts have noted that children and pregnant/child-bearing aged women are the most likely to practice geophagy, but it’s not limited to these demographics. As for the what, geophagy related earth is generally clay rather than soil. Where? How? Those who practice geophagy as their ancestors did in the same regions are as particular as the Otomacs were in harvesting said clay. Tribal/community wisdom passed down through the generations directs them to very specific sites. Usually, the clay is gathered by digging down a number of several inches – where microbial presence is substantially diminished compared to surface soil. Sometimes it is eaten as is. Other times it is mixed with water and used as a dip for food.

But why? Theories have abounded in scientific corners. Many experts traced the phenomenon to mineral supplementation. In other words, animals and humans ate earth to benefit from the nutrition of it – particularly minerals like calcium and iron. Numerous studies exist attempting to correlate anemia and earth eating. Some show that those who eat earth tend to be more iron deficient, but the earth routinely eaten by some of these groups is actually high in iron.  More questions arise from there. Is something in the earth they eat interfering with iron absorption? Were they already deficient before they started eating earth? Which came first: the chicken or the egg? Moreover, when anemic, geophagy-practicing children in one study were given iron supplementation, they still ate the clay. Is it culture then? Habit? Is it something else biological – or all of the above?

When scientists sampled earth from geophagic sites frequented by animals, they found that the earth contained only modest mineral content. In another study, however, scientists carefully compared earth samples taken directly from where the animals ate (“interior” earth) with those taken at the surface/other spots at the site. The samples taken where the animals had eaten actually showed more mineral content. (Now that’s a discerning palate!)

Just a few weeks ago, a meta-analysis on geophagy research was published that goes a long way in honing in on the sense behind the practice. Sera Young from Cornell University and her fellow researchers analyzed more than 300 recorded observations of animal geophagy and nearly 500 of human geophagy instances. The records related to particular practices, soil content, etc. pointed to a rationale that’s been gaining momentum in the past two decades.

Instead of hunger of mineral supplementation, Young and her team found the most compelling support for geophagy as digestive protection and support. Those who engage in geophagy the most often (children and pregnant women), the researchers noted, are the most “vulnerable” to “dietary chemicals, parasites, and pathogens.” The clays routinely eaten in geophagic practice showed little overall mineral content. They did, however, have one thing in common – clay content.

The clay itself, Young and others researchers have noted, is key. Certain kinds of clay has the power to ease stomach distress. Anyone who’s taken Kaopectate (pre-2003 in the U.S. and any year elsewhere) knows this. It acts as a natural binder to relieve diarrhea and can curb acidity. Bothered by nausea (as many pregnant women are)? Plagued by pathogen-induced diarrhea? It’s little wonder people traditionally sought out clay. It offers inherent medicinal properties.

But that’s not all. Specific clay varieties can actually enhance a person’s or animal’s nutritional potential. The types of geophagic clay ingested by animals and people disable toxic anti-nutrients found in regionally available plants. The knowledge that has been handed down – or instinct that was selected for – allowed people and animals to increase the variety of their diets and likely take advantage of alternative food sources when traditional foods were scarcer during inclement weather, pest infestation, etc. Young’s examination showed that both humans and animals benefitted from geophagy’s ability to counter natural plant toxins. The analysis affirms research done by others who have observed the effect of clay varieties on various natural toxins, including the glycoalkaloids of wild potatoes (PDF) or tannins in acorns.

Experts warn, however, that there’s an increasing danger to this traditional practice. For better and for worse, few if any of us across the globe live in Grok’s world anymore. Agricultural and industrial pollutants have found their way into corners more remote than we could possibly imagine. Even soil in less industrialized countries is bearing the chemical stamp of modernity. One recent study analyzed samples of African soil that was sold for geophagic purposes in various parts of Africa, Europe, and the U.S. Of particular concern to the researchers were the microbe and lead levels. Small levels of mercury and cadmium were also present.

Nonetheless, geophagy continues – in many traditional societies and in more “modern” regions where an increasing number of people are exploring geophagy’s protective and therapeutic effects. I’ve heard that some are using particular clay varieties to treat systemic cases of Candida or Crohn’s. I find the potential of traditionally eaten clays like kaolin, bentonite, and attapulgite – especially for these kinds of applications – compelling. As for obtaining pristine stores or supplements of these varieties, I’m not so won over.

Perhaps some of you in the Primal community practice or know folks who practice geophagy. Maybe you have sources – like the gentleman I met – who you know and trust. Maybe you have personal access to these kinds of clays and have the local resources to get your source thoroughly tested. That would be the way to do it, I’d say.

For the rest of us, there’s this. While it’s clear that geophagy played a role in our species’ evolution, we’re fortunate to have access to good sanitation and an infinite variety of foods that don’t require special formulations to aid digestion. I think there’s value in understanding how our ancestors lived and learned to thrive in their environments. There’s also value, however, in embracing the options we have today.

Thanks for reading, everyone. Let me know what you think. I’ll look forward to reading your thoughts.

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You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. God made dirt and dirt don’t hurt!

    Matthew Muller wrote on July 22nd, 2011
  2. I used to eat small dirt clumps as a child. Never got sick from it. but it wasn’t clay. It was topsoil. The area had been forest in the past and was cleared for house building. But an area of about a thousand square yards was never developed and a field of wild flowers and weeds grew there. Me and some neighborhood kids would pull some weeds, smooth the dirt, draw a ring and play marbles. We would also eat some of the small clumps of dirt. That time period was from about 1950 to about 56. When I read about all the stuff in refined carbs and modern food, those little dirtballs as we called them, start to look appealing. Great post!

    Michael Neibel wrote on July 22nd, 2011
  3. It’s an interesting idea, but I don’t think I’ll be sprinkling dirt on my lentil soup tomorrow. The pollutants, etc. seem like a difficult hurdle to overcome. But maybe there’s a future for dirt farmers. :)

    Todd wrote on July 22nd, 2011
  4. You mentioned it, but it should be stressed, that “clay” is not “dirt”. Clay beds were laid down sometimes millions of years ago … like salt deposits. If they are in the mountains, they are unlikely to be contaminated by anything. And historically, they were often “baked” which would get rid of parasites. Some clays are way better than others, which is why certain deposits were popular, with both natives and with animals, such as parrots, that eat the clay to neutralize toxic berries.

    There is a lot of research on clay use for animals. Clay helps prevent birth defects caused by mycotoxins, and normalizes gut flora for sick cows. But more important, it was pretty much part of everyone’s lives back when … we lived on dirt floors, drank water that was sitting on clay usually. I think the clay DOES interfere with absorptions of some things, but they are the things we don’t get along with, usually. Iron is a weird one, because although we need it, we usually have too much of it unless we have parasites (giving iron supplements to the Maasai makes them more prone to illness).

    Anyway, I’ve been taking clay on and off for years, and it’s only done good things. It might cause constipation if you aren’t getting enough fiber (it makes the food digest more thoroughly, so there is less bulk). It has saved many a family member from cases of “food poisoning”. In one case, someone I know was at a retreat where everyone who ate the chicken got very ill. She took her clay, got better in half an hour or so, then dosed everyone else who would take it. They all got better too. It might seem weird, but IT WORKS and it’s cheap.

    HeatherT wrote on July 22nd, 2011
  5. Sure, Mark. You eat the dirt and I’ll eat the bacon. Deal.

    Allie wrote on July 22nd, 2011
  6. Growing up we played all day out in the woods, rode our horses and every time we ate something our hands had dirt on them ad we didn’t care, we ate the dirt to, also my dad was a survival instructor in Wash State back in the 70′s& they were taught to eat stuff from the dirt w/out rinsing in off, so I learned that to..Ok, so now I do rinse stuff & wash my hands more, but my mother always told me the reason I don’t have any allergies,don’t have asima & no real health issues is due to eating dirt”not intentional”… So to make a long story short, when I see someone with a baby, I say ” Let them eat dirt” build up that little immune system…

    Shannon wrote on July 22nd, 2011
  7. Just now reading “Life on the Mississippi” and Twain talks about the old timers, which would have been early 1800′s, not letting sediment settle in drinking water from the river but stirring it up. Touting benefits much as described. I had not taken it as literal truth,but I suppose it was.

    Peter wrote on July 22nd, 2011
  8. I buy bentonite clay from Mountain Rose Herbs. If you drink it, mix about a teaspoon in a small glass of water, let it sit a few minutes, and drink it, trying to drink the clay itself after it settles, although that’s not necessary because it the water becomes like a colloidal solution, full of trace minerals. But swallowing the clay is beneficial to the digestion. Follow that with anothe glass of water to help it through your body.
    You can also use the clay in a bath. Add some hot water, mix about a cup of clay, mix thoroughly to help it dissolve, then add tepid or warm water and soak. This will draw impurities out of your body. Masks work the same way.

    Vicki wrote on July 25th, 2011
  9. I for one love it when my mom cooks collards for me, because they’re always gritty from where they’re not washed off.

    And I also used to eat my own mud pies when I was a kid.

    Vicki wrote on July 26th, 2011
  10. Alex Grace mentioned stone soup from when things were hard “in the old country”, people used to boil up stones for soup… ah, they had stone soup in the U.S. too.

    Dolly Parton told Johnny Carson about how her mother would send her out into the fields when she was very young and poor to pick out a stone for the soup.

    clark wrote on July 26th, 2011
  11. I was practicing geophagy but I had know idea there was a name for it! I took bentonite clay for a long time to treat really bad candida when I was a child. I also went off sugar, yeast and wheat at the time. I wish I’d known about Primal back then and I would have cut out all grains! But the clay mixed with caproil and psyllium seed husks really did clean out the system, but I think there must be a less damaging way to do it!

    Robin wrote on August 7th, 2011
  12. The astronauts ate clay when they went to space because it was the most absorbed source of calcium available.

    http://www.youtube.com/watch?v=3o7zn7e5Ep4

    Stephen wrote on December 19th, 2011
  13. Hi folks, i had an interesting past when in my childhood I have ingested dirt in forms of bricks, cement, chalk, slate pencil, fuller’s earth, plater of paris , wall putty , wall plaster and mud.

    Have given it all up after i turned 15 and almost lost my 4 teeth due to erosion.

    I still sometimes have cravings for all of these but have turned more sensible ass to not to ingest such things which harm you later in life.

    I feel healthier and have developed a strong liking for fruits and veggies ever since I decided not to have dirt.

    Good luck to all…

    Shoren wrote on March 26th, 2012
  14. I eat a yes cup size of clay a day when available, and am always anaemic

    julia wrote on April 27th, 2012
  15. I want to stop but I cant

    julia wrote on April 27th, 2012
  16. African Elephants eat lots of dirt! Scientists tagged several elephants with trackers and studied their migrational patterns for a year. The elephants had gatherings at specific sites. When the researchers visited these sites, they found barren patches of land. Elephants “mine” the earth for the rich mineral content.

    the happy girlfriend wrote on August 27th, 2012
  17. wanda wrote on October 20th, 2012
  18. If anyone wants to buy White Dirt From GA
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    Lesliecinga wrote on December 21st, 2012
  19. what is the environmental effect of geophagy? many women especially pregnant eat soil in zambia. infact it is sold in markets

    maybin yamba wrote on May 8th, 2013

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