Iodine in biology
The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for iodine in 2000. For people age 14 and up, the iodine RDA is 150 μg/day; the RDA for pregnant women is 220 μg/day and the RDA during lactation is 290 μg/day. For children 1–8 years, the RDA is 90 μg/day; for children 8–13 years, 130 μg/day. As a safety consideration, the IOM sets tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient. The UL for iodine for adults is 1,100 μg/day. This UL was assessed by analyzing the effect of supplementation on thyroid-stimulating hormone. Collectively, the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes (DRIs).
Vanadium
Deficiencies in vanadium result in reduced growth in rats. The U.S. Institute of Medicine has not confirmed that vanadium is an essential nutrient for humans, so neither a Recommended Dietary Intake nor an Adequate Intake have been established. Dietary intake is estimated at 6 to 18 µg/day, with less than 5% absorbed. The Tolerable Upper Intake Level (UL) of dietary vanadium, beyond which adverse effects may occur, is set at 1.8 mg/day.