It’s been hypothesized that iodized salt is responsible for a large part of the Flynn Effect, the gradual increase in IQ around the world over the last hundred years or so.
Interesting article on the Flynn Effect - http://www.bbc.com/future/story/20160929-our-iqs-have-never-been-higher-but-it-hasnt-made-us-smart
I didn’t realize how important iodine is to human health. We have better nutrition today than we did even during WWI. The social and economic impact was surprising and I think everyone should read through this, it was eye opening to say the least.