In the early 20th century, Switzerland was plagued by high rates of goitre and cretinism, with these conditions affecting a significant portion of the population. The cause of these conditions was a lack of iodine in the diet, leading to thyroid dysfunction. A young doctor named Heinrich Hunziker proposed a solution: adding iodine to table salt. Despite opposition and skepticism from the medical community, Hunziker’s theory proved to be true. In 1922, iodized salt was introduced in Switzerland, leading to a rapid decline in goitre and cretinism cases. This simple and effective solution was a breakthrough in the field of public health.
https://www.lrb.co.uk/the-paper/v45/n23/jonah-goodman/a-national-evil