Chromium is widely distributed throughout the food supply. A number of studies have shown chromium stimulates insulin action in the body. Daily requirements for chromium could not be established because not enough information exists to determine a relationship between a particular dose of the nutrient and insulin response, according to the report. Based on current estimated consumption by the general population, an intake of 35 mg for men and 25 mg for women was recommended. Some forms of chromium are known to be toxic, but those are not present naturally in foods or contained in currently available dietary supplements.
Copper is necessary for proper development of connective tissue, nerve coverings, and skin pigment.
The new RDA is 900 mcg a day for both men and women. No more than 10 mg a day should be consumed, as too much causes liver damage. Based on research into how much iodine the thyroid needs to properly regulate enzyme and metabolic processes, an RDA of 150 mg a day was established for both men and women. Most food sources have little iodine, but iodized salt is a dietary source. To avoid over-absorption of iodine by the thyroid, adults should not consume more than 1.1 mg daily.