Bromine and fluoride and chlorine are everywhere-and salt has been demonized.
My endocrinologist says very few people are iodine deficient nowadays but if you cook everything from scratch and don’t use iodized salt, don’t eat fish or seaweed and are continually exposed to things that cancel out iodine it stands to reason that you might need a little iodine.
I looked up iodine a while ago and cranberries (depending on where grown) have a huge amount of iodine, also some seaweeds. I started using kelp daily and canned about 25 jars of home made cranberry sauce. :-D
I think that bromine and flouride and chlorine can be avoided by choices made.
your endo is completely wrong and in fact most of us are very deficient in iodine. glad you get it.