~~paper from 1972 that discusses the fact that those with a higher dietary intake of Iodine required more radioiodine for scanning purposes.~~
"Ingestion of bread rich in Iodine is of potential clinical importance, especially in the presence of recent data indicating that an increase in dietary Iodine may be a widespread phenomenon in the U.S.A. (Oddie et al., 1970). An iodine intake of as little as 300 ug daily has been shown to partially suppress 24-hour thyroidal iodine uptake tests. Severe suppression of uptake is achieved with 1,000 ug daily (Saxena
et al., 1963). Regular dietary iodine plus four slices of iodine-rich bread daily would readily achieve suppressive levels of iodine intake."
"Three hundred twenty-eight 24-hour I-131 thyroidal uptake determinations were performed from February 15 to May 14, 1968, in the Section of Nuclear Medicine.
In a recent study from Alabama, Pittman, Dailey and Beschi6 showed that the mean normal 24-hour thyroidal radioiodine uptake decreased in that area from 28.6 percent to 15.4 percent during the preceding decade, largely as a consequence
of the increasing iodine content of bread resulting from newer baking methods."