Therefore, vitamin D 2 is equally as effective as vitamin D 3 in maintaining 25-hydroxyvitamin D status. The 1000 IU dose of vitamin D 2 or vitamin D 3 did not raise 25-hydroxyvitamin D levels in vitamin D-deficient subjects above 30 ng/ml.Ĭonclusion: A 1000 IU dose of vitamin D 2 daily was as effective as 1000 IU vitamin D 3 in maintaining serum 25-hydroxyvitamin D levels and did not negatively influence serum 25-hydroxyvitamin D 3 levels. The 25-hydroxyvitamin D 3 levels did not change in the group that received 1000 IU vitamin D 2 daily. The circulating levels of 25-hydroxyvitamin D (mean ± sd) increased to the same extent in the groups that received 1000 IU daily as vitamin D 2 (baseline 16.9 ± 10.5 ng/ml 11 wk 26.8 ± 9.6 ng/ml), vitamin D 3 (baseline 19.6 ± 11.1 ng/ml 11 wk 28.9 ± 11.0 ng/ml), or a combination of 500 IU vitamin D 2 and 500 IU vitamin D 3 (baseline 20.2 ± 10.4 ng/ml 11 wk 28.4 ± 7.7 ng/ml). Results: Sixty percent of the healthy adults were vitamin D deficient at the start of the study.
Subjects and Design: This was a randomized, placebo-controlled, double-blinded study of healthy adults ages 18–84 yr who received placebo, 1000 IU vitamin D 3, 1000 IU vitamin D 2, or 500 IU vitamin D 2 plus 500 IU vitamin D 3 daily for 11 wk at the end of the winter. Objective: Our objective was to determine whether vitamin D 2 was less effective than vitamin D 3 in maintaining serum 25-hydroxyvitamin D levels or increased the catabolism of 25-hydroxyvitamin D 3. Context: Two reports suggested that vitamin D 2 is less effective than vitamin D 3 in maintaining vitamin D status.