What’s the difference between plain salt and iodize salt

See if this helps!

https://en.m.wikipedia.org/wiki/Iodised_salt

https://www.epicurious.com/archive/blogs/editor/2009/09/sea-salt-or-table-salt-which-is-healthier.html

http://www.differencebetween.net/object/comparisons-of-food-items/difference-between-salt-and-iodized-salt/

Iodized salt has iodine added which in small quantities is good for us. It prevents goiters which was a problem before iodine was added to salt. You cannot taste the iodine, and since it is good for you, buy the iodized salt for every day use.

Basically , you need a bit of iodine to make your brain work better. It’s not in many food stuffs, but lots of people do use salt, so it’s added to table salt.

https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/sea-salt/faq-20058512

Iodized salt has iodine added to it. People used to have goiters in their necks due to lack of iodine in the early 1930's and on up to late 1900's. They added iodine (very minimal amount) to salt to help and it did. You seldom see anyone get a goiter in their neck now due to lack of iodine. Eating seafoods will also provide the iodine you need. Not everyone lives close to the ocean though so this was the answer to a health need.