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.
Nascent iodine (dietary supplement)
The diatomic form of elemental iodine I2, has no electrical charge. Monoatomic iodine also has no electrical charge, but is unstable and highly reactive (free radical, labeled as an I with a dot, I* ). It can be produced by exposing I2 to ultraviolet light. Electric and magnetic fields won't do it, as is sometimes incorrectly suggested.I should mention a few points about Edgar Cayce's atomidine. This famous visionary wrote several articles about the best form of iodine supplement (18). Some claim that this was iodine trichloride, but that cannot be true as this compound is toxic by ingestion and damaging to mucous membranes. It decomposes to ICl and poisonous gas Cl2 at 77 degrees C and also in water at room temperature (19). Most likely Cayce's atomidine was simply a 1% iodine solution (I2) in 95% ethanol. I am surprised that there are educated people, even medical doctors who claim that "elemental monoatomic iodine" preparations (Atomidine, Nascent Iodine etc.) are the best forms of iodine supplements. May be it has something to do with efficient marketing? Elemental Iodine (I2) is soluble in glycerin. Replacement of ethanol with glycerol indeed makes these supplements more consumption-friendly, so they are sold by some vendors as superior products to Cayce's ethanol-formulated one. Personally, I think glycerol-based I2 supplements are inferior to iodides; however, they are excellent antiseptics.The best and safest form of iodine supplementation for a healthy adult is iodide. Iodides are naturally produced in larger quantities by various seaweeds.