The U.K. Food Standards Agency is advising pregnant women not to eat clay, sometimes known as ‘sikor’ or ‘shikor mati’, because it may contain high levels of toxic chemicals that could harm their babies.

Clay or earth is sometimes consumed in Asia and Africa, particularly by pregnant women who believe that eating it is beneficial during pregnancy. It is not known how common clay consumption is in the UK, but recent research carried out by De Montfort University found products imported from Bangladesh on sale in shops in Birmingham, Leicester and Luton.

Tests carried out on samples of this baked clay found high levels of lead and arsenic. Exposure to arsenic can be associated with an increased risk of lung, skin and bladder cancer. Exposure to lead by pregnant women, infants or children poses a risk to the development of the brain, which can affect intellectual performance.