Eating dirt or clay could be good for the stomach, researchers at New York's Cornell University have claimed.
The scientists claim that eating dirt, or geophagy, is a common practice in many cultures throughout the world, after analysing more than 480 different examples.
The researchers, writing in the Quarterly Review of Biology, claim that the most likely explanation is that dirt and clay could act as a shield against plant toxins or ingested parasites. It may also be a way of providing key nutrients, such as zinc, calcium or iron, they claim.
The news might come as a relief to parents who see their children putting dirt into their mouths.
Dr Sera Young, who led the research said: "We hope this paper stimulates more research.
"More importantly, we hope readers agree it is time to stop regarding geophagy as a bizarre, non-adaptive gustatory mistake.
"With these data, it is clear that geophagy is a widespread behaviour in humans that occurs during both vulnerable life stages and when facing ecological conditions that require protection."
Posted by Robert Mair on 7.6.11 Comment on this article by sending it to: firstname.lastname@example.org