More than eight million Chinese people have reduced IQ levels because of a shortage of iodine in their diets, according to a survey team from the China National Committee on Care for Children. Speaking last week Ji Xiaocheng, the senior member of the team, said that the potential for iodine deficiency in China was huge: about 400 million people—one in every three Chinese—live in regions where the natural iodine supply is far from sufficient.

Only recently has the Chinese government realised the cost of diseases caused by iodine deficiency. According …