A 250 μg/week dose of vitamin D was as effective as a 50 μg/d dose in healthy adults, but a regimen of four weekly followed by monthly doses of 1250 μg raised the risk of hypercalciuria.
Br J Nutr. 2013 Nov;110(10):1866-72. doi: 10.1017/S000711451300113X. Epub 2013 Apr 18.
Sara R. Zwart a1, Howard Parsons a2, Michael Kimlin a3, Sheila M. Innis a2, James P. Locke a4 and Scott M. Smith a4 scott.m.smith at nasa.gov
a1 Division of Space Life Sciences, Universities Space Research Association, Houston, TX, USA
a2 Division of GI/Nutrition, Department of Paediatrics, British Columbia Children's Hospital, Vancouver, BC, Canada
a3 Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
a4 Human Health and Performance Directorate, National Aeronautics and Space Administration Lyndon B. Johnson Space Center, Mail Code SK3, 2101 NASA Parkway, Houston, TX 77058, USA
The risk of vitamin D insufficiency is increased in persons having limited sunlight exposure and dietary vitamin D. Supplementation compliance might be improved with larger doses taken less often, but this may increase the potential for side effects. The objective of the present study was to determine whether a weekly or weekly/monthly regimen of vitamin D supplementation is as effective as daily supplementation without increasing the risk of side effects.
Participants were forty-eight healthy adults who were randomly assigned for 3 months to placebo or one of three supplementation regimens: 50 μg/d (2000 IU/d, analysed dose 70 μg/d), 250 μg/week (10 000 IU/week, analysed dose 331 μg/week) or 1250 μg/week (50 000 IU/week, analysed dose 1544 μg/week) for 4 weeks and then 1250 μg/ month for 2 months.
Daily and weekly doses were equally effective at increasing serum 25-hydroxyvitamin D, which was significantly greater than baseline in all the supplemented groups after 30 d of treatment. Subjects in the 1250 μg treatment group, who had a BMI >26 kg/m2, had a steady increase in urinary Ca in the first 3 weeks of supplementation, and, overall, the relative risk of hypercalciuria was higher in the 1250 μg group than in the placebo group (P=0·01).
Although vitamin D supplementation remains a controversial issue, these data document that supplementing with ≤ 250 mg/week (≤ 10 000 IU/week) can improve or maintain vitamin D status in healthy populations without the risk of hypercalciuria, but 24 h urinary Ca excretion should be evaluated in healthy persons receiving vitamin D3 supplementation in weekly single doses of 1250 μg (50 000 IU).
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