when did they start putting iodine in salt
Iodised salt In the U.S. in the early 20th century, goitre was especially prevalent in the region around the Great Lakes and the Pacific Northwest.[24] David Murray Cowie, a professor of paediatrics at the University of Michigan, led the U.S. to adopt the Swiss practice of adding sodium iodide or potassium iodide to table and cooking salt. On May 1, 1924, iodised salt was sold commercially in Michigan.[25] By the fall of 1924, Morton Salt Company began distributing iodised salt nationally. There was a gradual increase in average intelligence of 1 standard deviation, 15 points, in iodine-deficient areas and 3.5 points nationally.[26]