New measurement technique lowers estimated vitamin D recommended daily allowance

(The Endocrine Society) After re-measurement of vitamin D by improved technology, the Recommended Dietary Allowance (RDA) for vitamin D intake drops from 800 to 400 International Units (IU) per day, new research reports. The results of the study will be presented Sunday, April 2, at ENDO 2017, the annual scientific meeting of the Endocrine Society, in Orlando, Fla.