[The full text of this article is available free at http://jcem.endojournals.org/cgi/rapidpdf/jc.2007-2530v1]
Background: Hypovitaminosis D [insufficient vitamin D] is prevalent in youth worldwide, but the safety of vitamin D at doses exceeding 200 IU/day is unknown in this age group.
We assessed the safety of high doses of vitamin D3 administered to apparently healthy school children.
Biochemical variables were monitored at 0, 2, 4, 6, 8 weeks, and 8 weeks off therapy in the short term study and at 0, 6 and 12 months in the long term study.
In both the short term and long term studies, mean serum calcium and 1,25-OHD levels did not change in any group.
In the short term study, mean 25-OHD concentrations increased from 44 (+/- 11) ng/ml to 54 (+/- 19) ng/ml in the treated groups (P=0.033).
In the long term study, mean 25-OHD levels increased from 15+/-8 to 19+/-7 ng/ml (p<0.0001) in subjects receiving 1400 IU/wk; and from 15+/-7 to 36+/-22ng/ml in the group receiving 14,000 IU/wk (p<0.0001).
No subject developed vitamin D intoxication.
Conclusion: Vitamin D3 at doses equivalent to 2,000 IU/day for one year is safe in adolescents and results in desirable vitamin D levels.
Source: The Journal of Clinical Endocrinology & Metabolism, April 29, 2008. [Epub ahead of print] PMID: 18445674, by Maalouf J, Nabulsi M, Vieth R, Kimball S, El-Rassi R, Mahfoud Z, El-Hajj Fuleihan G. Schools of Medicine and Health Sciences, American University of Beirut, Lebanon; Department of Nutritional Sciences, University of Toronto, Canada. [E-mail: Ghada E-Hajj Fuleihan, MD, MPH