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.
Vitamin K
The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for vitamin K in 1998. The IOM does not distinguish between K and K – both are counted as vitamin K. At that time, sufficient information was not available to establish EARs and RDAs for vitamin K. In instances such as these, the board sets Adequate Intakes (AIs), with the understanding that at some later date, AIs will be replaced by more exact information. The current AIs for adult women and men ages 19 and up are 90 and 120 μg/day, respectively. AI for pregnancy is 90 μg/day. AI for lactation is 90 μg/day. For infants up to 12 months, the AI is 2.0-2.5 μg/day; for children ages 1–18 years the AI increases with age from 30 to 75 μg/day. As for safety, the IOM sets tolerable upper intake levels (known as ULs) for vitamins and minerals when evidence is sufficient. Vitamin K has no UL, as human data for adverse effects from high doses are inadequate. Collectively, the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes.