scientists in Canada after analysing soils eaten by people in China, Zimbabwe and the us have concluded that eating soils have their own advantages. Susan Aufreiter of the University of Toronto and William Mahaney of York University, also in Toronto, used a technique called instrumental neutron activation analysis to get a precise chemical breakdown of the soil samples.

The first sample, a fine, light yellowish soil from China's Hunan province, was used as "famine food' in the 1950s. This soil is rich in iron, calcium, magnesium, manganese and potassium