Iodized salt is so commonplace in the U.S. today that you may never have given the additive a second thought. But new research finds that humble iodine has played a substantial role in cognitive improvements seen across the American population in the 20th century.
Iodine is a critical micronutrient in the human diet—that is, something our bodies can’t synthesize that we have to rely on food to obtain
—and it’s been added to salt (in the form of potassium
iodide) since 1924. Originally, iodization was adopted to reduce the
incidence of goiter, an enlargement of the thyroid gland. But research
since then has found that iodine also plays a crucial role in brain
development, especially during gestation.
today is the leading cause of
preventable mental retardation in the world. It’s estimated that nearly
one-third of the world’s population has a diet with too little iodine in
it, and the problem isn’t limited to developing countries—perhaps one-fifth of those cases are in Europe (pdf), where iodized salt is still not the norm.
For the rest of the story: http://blogs.discovermagazine.com/crux/2013/07/23/how-adding-iodine-to-salt-boosted-americans-iq/#.UfGoJ6x0Zdg