Answer: Kosher salt does not contain any iodine, a critical mineral that supports hormone function and metabolism. But don’t fear—you’d have to live in a food desert to have an iodine-deficient diet. Coarse-grained sea salt, table salt, and seafood contain the nutrient. (A 6-ounce portion of salt-water fish supplies more than 4 times your daily need of 150 micrograms). Many commercial products made with salt (frozen bread dough, for example), eggs, and dairy products are other sources. Also plants can contain the mineral, thanks to iodine-rich soil, so eating a variety of vegetables can contribute to your intakes, too.