In 1924 they started putting iodine in table salt. Within ten years, the neck swelling that ran through the Midwest for generations was basically gone. It worked.
For the next fifty years your bread carried it too. Bakers used an iodine-based dough conditioner — a couple of slices covered your whole day without you knowing.
Then in the 1980s the bakers quietly switched to a bromine-based one instead. It was cheaper. Bromine is another one of iodine’s cousins — and just like fluoride, it pushes iodine out.
Around the same time everyone moved to sea salt, kosher salt and pink Himalayan salt. They cost more, so people assumed they were better. Almost none of them have any iodine at all. Nobody puts that on the box.
Add it up and government testing shows Americans lost half their iodine between the 1970s and the 1990s. Nothing was ever banned. Nothing was ever announced. It was just swapped out while you weren’t looking.