It may be regarded as a strange phenomenon in the developed world, but tucking into a generous helping of mud pie is perhaps the most natural way to protect the stomach against toxins, parasites and pathogens, a new study suggests.

After sifting through 480 reports compiled by missionaries, plantation doctors, explorers and anthropologists from around the world, researchers at Cornell University concluded that human geophagy -- the act of eating dirt -- is most likely driven by the belief that earth and clay absorb dangerous toxins and act as a shield against pathogens.