`EAT DIRT' AS GOOD AS `BON APPETIT'.

Byline: Alison Motluk The New York Times

Eating soil can be good for you. This is the verdict of scientists in Canada who have analyzed soils eaten by people in China, Zimbabwe and the United States. The samples they looked at contained exactly the nutrients needed to provide the benefits that soil-eaters report.

People have a long history of eating earth: Romans made medicinal tablets from soil and goats' blood; Germans in the last century substituted fine clay for butter on their bread; and in some African countries, clay is still sold as a digestive remedy. Health professionals nowadays consider the habit to be a symptom of mental illness.

Susan Aufreiter of the University of Toronto and William Mahaney of York University, also in Toronto, wondered if there was any evidence to support ``geophagy'' - eating earth for medicinal reasons.

They used a technique called instrumental neutron activation analysis to get a precise chemical breakdown for each of three soil samples.

The first sample, a fine, light yellowish soil from China's Hunan province, was used as ``famine food'' as recently as the 1950s. The second was a soft clay from Stokes County in North Carolina, said to be good for general health. The third sample, a red soil from termite mounds, was collected in Zimbabwe, where it is eaten to soothe upset stomachs.

The Chinese soil turned out to be rich in iron, calcium, vanadium, magnesium, manganese and potassium - all of which would be in short supply in times of famine. The North Carolina soil was rich in iron and iodine, important for the health of both children and women of childbearing age, and often missing from the diets of the poor.

``It's an insult to say `eat dirt,' '' Aufreiter says. ``But poor blacks in the South did, and they were right.'' In the soil from Zimbabwe, the researchers found kaolinite, the principal ingredient in the commercial diarrhea treatment, Kaopectate.

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Photo: People have a long history of eating earth: Romans made medicinal tablets from soil and goats' blood; Germans in the last century substituted fine clay for butter on their bread; and in some African countries, clay is still sold as a digestive remedy.