By comparing the serum concentrations of the predominant circulating form of vitamin D – 25-hydroxyvitamin D (25(OH)D) – investigators were able to determine the optimal serum level needed to lower an individual’s risk of developing type 1 diabetes.
Based mainly on results of this study, Garland estimates that the level of 25(OH)D needed to prevent half the cases of type 1 diabetes is 50 ng/ml. A consensus of all available data indicates no known risk associated with this dosage.
“While there are a few conditions that influence vitamin D metabolism, for most people, 4000 IU per day of vitamin D3 will be needed to achieve the effective levels,” Garland suggested. He urges interested patients to ask their health care provider to measure their serum 25(OH)D before increasing vitamin D3 intake.
“This beneficial effect is present at these intakes only for vitamin D3,” cautioned Garland. “Reliance should not be placed on different forms of vitamin D and mega doses should be avoided, as most of the benefits for prevention of disease are for doses less than 10,000 IU/day.”
The study has been published in the December issue of Diabetologia.