A significant source of declining iodine levels in humans can also be traced to increased bromide found in food and medications. Most notably potassium iodate was used as a bread conditioner until the 1950s when it was substituted for potassium bromate. [0]
Excess bromide levels displace the iodide stored in the thyroid and is a contributing factor to the described increase of groiter. Bromide also has the added drawback of increased cancer risk and has now been banned in California [1] [2].
Yes, and there is anecdotal evidence of improved health and loss of gluten allergies when traveling to Europe for vacation! (Probably confounding factors but still worth considering)
Excess bromide levels displace the iodide stored in the thyroid and is a contributing factor to the described increase of groiter. Bromide also has the added drawback of increased cancer risk and has now been banned in California [1] [2].
[0] https://pmc.ncbi.nlm.nih.gov/articles/PMC3916868/
[1] https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml...
[2] https://web.archive.org/web/20131203041405/http://www.oehha....