In 1917, David Marine, an American pathologist, re-started the virtually abandoned practice of adding iodine to the diet to prevent goiter. During 1916 to 1920 he administered 3 grains of NaI, taken daily in drinking water for two 10 day periods, spring and autumn to approximately 5000 schoolgirls in Akron, OH. Those who refused became the “control” group. The efficacy was an astonishing 100 % (Arch Int Med 1920; 25:661). None in the iodide group, but nearly ½ in the control group, had goiter. Of those with goiter at the beginning more than 2/3 became normal on later exam. Similar findings were obtained in West Virginia and Michigan leading to recommend that all table salt be standardized to 0.01 % iodide.

Over the next few years, he and colleagues published a series of papers reporting a significantly decreased frequency of goiter in children treated with iodine (0.2%), compared to children who did not receive iodine supplementation (>25%).

In the U.S., iodized salt first became available on grocery shelves in Michigan on May 1, 1924, spurred largely by the series of reports by Cowie, Marine, and others in the preceding few years