It was my supposition years ago that the reason that iodine fortification of foodstuffs was reduced/eliminated in the eighties was due to the fact that doctors were having a difficult time reading radioactive thyroid scans because people's thyroids were saturated with iodine.
Unfortunately the curezone search function is not working at the moment. When I am able to locate a link to the original post on the 70s study that details that difficulty with radioactive scans I will do so, and update this post.
From Google News Archive: The Toledo Blade, 02/28/1981
A close-up of the portion that deals with radioactive iodine thyroid scans:
And this article, from The Lakeland Ledger, 11/21/85. Please note the headline:
EXCESSIVE IODINE IN OUR DIETS RAISES QUESTIONS ON ITS HEATH EFFECT
and from the last paragraph:
To date, there have been NO PROBLEMS associated with the increased iodine in our food supply.
I just don't know what to say about this. How on earth did reports that radioactive iodine uptake was limited because people were saturated turn into a recommendation by the United States Food and Nutrition Board that "adventitious sources of iodine in the American Food System" be replaced by compounds containing little or no iodine? When there were NO PROBLEMS associated with the "excess" iodine?
More information on recommendation of food and nutrition Board: