Upper Intake Level for Vitamin D Seen as Too Low

No events of hypercalcemia and no change in urinary calcium levels have occurred. The investigators have received funding to extend the study.

With the results of his study and after a review of the literature, Dr. Vieth concluded that about 1 mg/day or 40,000 IU/day of vitamin D₃ might be the threshold at which toxicity begins.

But the actual UL for vitamin D should be about 10,000 IU/day, or 250 mcg/day, Dr. Vieth suggested. This is not an RDA, but it is a level not likely to cause harm in most individuals.