If you interested please read the Institute of Medicine's 2010 report on vitamin D and calcium intake.
Click here for on-line access to the report
The committee of scientists, convened by the National Academies' Institute of Medicine, doubled the upper level of vitamin D that people that people between the ages of 9 and 50 can safely take in any given day from 2,000 to 4,000 IU.
Please click here to read a commentary in Science News