Listen to this PodcastMore 60-Second Science
There’s a habit that’s had scientists puzzled: the practice of geophagy—eating dirt. People around the world munch on dirt, and not just when they’re hungry enough to eat anything. So is there any nutritional or health benefit? A meta-analysis published in the Quarterly Review of Biology may offer a clue. [Sera Young et al., "Why on Earth?: Evaluating Hypotheses about the Physiological Functions of Human Geophagy," in press]
Researchers collected more than 480 reports from missionaries, plantation doctors, explorers and anthropologists. These included who was eating dirt and under what circumstances. Seems that dirt doesn’t offer much in the way of nutrition—but it may protect against toxins, pathogens and parasites.
Dirt is most commonly eaten by women in early stages of pregnancy and preadolescent children. Both are particularly at risk from parasites and pathogens. Also, people tend to eat dirt when they’re suffering from gastrointestinal distress. The distress probably doesn’t come from the dirt, which is usually clay found deep in the ground and that doesn’t house pathogens. Plus people often boil the clay before eating.
Scientists say more research is needed to confirm the hypothesis that dirt has health benefits. But they hope this offers evidence that eating dirt isn't, well, as bizarre as it may seem.—Cynthia Graber
[The above text is an exact transcript of this podcast.]
See what we're tweeting about
4 Comments
Add CommentAs a kid I was very dirty and always making a mess. I credit my early years of dirtiness to my never getting sick and having no allergies. Millions of years of dirty evolution can't be completely wasted.
Reply | Report Abuse | Link to thisMost bacteria live in soil. It is therefore not surprising that earthworms that eat such a wide range of bacteria are themselves made up of an extremely rich range of proteins in their bodies. Perhaps when we eat soil we are increasing our range and equilibrium of gut bacteria. Perhaps we should also farm earthworms instead of vertebrates to eliminate starvation and under-nourishment in the world.
Reply | Report Abuse | Link to this"the dirt, which is usually clay found deep in the ground and that doesn’t house pathogens."
Reply | Report Abuse | Link to thisThat is a significant piece of information. Clay has properties that allow it to absorb materials. A mixture of clay and charcoal will both dilute and absorb and carry away many toxins on the way through the digestive system.
According to Wikipedia, a clay compound was used as anti-diarrhea in Kaopectate :
Reply | Report Abuse | Link to this«Kaolinite is a clay mineral. Rocks that are rich in kaolinite are known as china clay, white clay, or kaolin. A folk medicine use is to soothe an upset stomach, similar to the way parrots (and later, humans) in South America originally used it». «Kaolin is, or has been, used as the active substance in liquid anti-diarrhea medicines such as Kaomagma and Kaopectate. Such medicines were changed away from aluminium substances due to a scare over Alzheimer's disease, but have since changed back to compounds containing aluminium as they are more effective»
in «Kaolinite» http://en.wikipedia.org/wiki/Kaolinite#Medicinal_and_culinary_uses