Salt
The amount of iodine and the specific iodine compound added to salt varies from country to country. In the United States, the Food and Drug Administration (FDA) recommends [21 CFR 101.9 (c)(8)(iv)] 150 micrograms of iodine per day for both men and women. US iodized salt contains 46–77 ppm (parts per million), whereas in the UK the iodine content of iodized salt is recommended to be 10–22 ppm.
Ethylenediamine dihydroiodide
EDDI is used as an additive in pet food and cattle feed with high bioavailability. Used to prevent iodine deficiency, this salt is one of the major uses of the element iodine. The United States Food and Drug Administration suggests a limit of intake to 50 mg/head/day. Although EDDI is generally recognized as safe (GRAS) only as a nutrient source of iodine, administration of EDDI also has preventative effects on foot rot in cattle.