what is an iu in vitamins?
IU. The IU is an International Unit, usually used to measure fat soluble vitamins including Vitamin A, D and E. The conversion of IU to mg varies depending on the nutrient. VITAMIN A. One milligram of beta carotene = 1667IU of Vitamin A activity. 15mg of beta carotene = 25,000IU of Vitamin A activity.