Vitamin D2 is as effective as vitamin D3 in maintaining circulating concentrations of 25-hydroxyvitamin D

Abstract

Context: Two reports suggested that vitamin D2 is less effective than vitamin D3 in maintaining vitamin D status.

Objective: Our objective was to determine whether vitamin D2 was less effective than vitamin D3 in maintaining serum 25-hydroxyvitamin D levels or increased the catabolism of 25-hydroxyvitamin D3.

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 D3, 1000 IU vitamin D2, or 500 IU vitamin D2 plus 500 IU vitamin D3 daily for 11 wk at the end of the winter.

Results: Sixty percent of the healthy adults were vitamin D deficient at the start of the study. The circulating levels of 25-hydroxyvitamin D (mean+/-sd) increased to the same extent in the groups that received 1000 IU daily as vitamin D2 (baseline 16.9+/-10.5 ng/ml; 11 wk 26.8+/-9.6 ng/ml), vitamin D3 (baseline 19.6+/-11.1 ng/ml; 11 wk 28.9+/-11.0 ng/ml), or a combination of 500 IU vitamin D2 and 500 IU vitamin D3 (baseline 20.2+/-10.4 ng/ml; 11 wk 28.4+/-7.7 ng/ml). The 25-hydroxyvitamin D3 levels did not change in the group that received 1000 IU vitamin D2 daily. The 1000 IU dose of vitamin D2 or vitamin D3 did not raise 25-hydroxyvitamin D levels in vitamin D-deficient subjects above 30 ng/ml.

Conclusion: A 1000 IU dose of vitamin D2 daily was as effective as 1000 IU vitamin D3 in maintaining serum 25-hydroxyvitamin D levels and did not negatively influence serum 25-hydroxyvitamin D3 levels. Therefore, vitamin D2 is equally as effective as vitamin D3 in maintaining 25-hydroxyvitamin D status.

Figure 1

Mean (± sem) serum 25(OH)D levels after oral administration of vitamin D₂ and/or vitamin D₃. Healthy adults recruited at the end of the winter received placebo (•; n = 14), 1000 IU vitamin D₃ (D₃, ▪; n = 20), 1000 IU vitamin D₂ (D₂, ▴; n = 16), or 500 IU vitamin D₂ and 500 IU vitamin D₃ [D₂ and D₃, ♦; n = 18) daily for 11 wk. The total 25(OH)D levels are demonstrated over time. *, P = 0.027 comparing 25(OH)D over time between vitamin D₃ and placebo; **, P = 0.041 comparing 25(OH)D over time between 500 IU vitamin D₃ plus 500 IU vitamin D₂ and placebo; ***, P = 0.023 comparing 25(OH)D over time between vitamin D₂ and placebo.

Figure 2

Effect of vitamin D₂ or vitamin D₃ on serum 25(OH)D₂ and 25(OH)D₃ levels. Serum levels of 25(OH)D₂ (▪) and serum 25(OH)D₃ (♦) were measured in healthy subjects receiving 1000 IU vitamin D₂ (A), 1000 IU vitamin D₃ (B), or 500 IU vitamin D₂ plus 500 IU vitamin D₃ (C) daily for 11 wk. Results are presented as means ± sem over time. *, P < 0.0001 comparing 25(OH)D₂ between baseline and 11 wk (A); *, P < 0.0001 comparing 25(OH)D₃ between baseline and 11 wk (B); *, P = 0.0014 comparing between 25(OH)D₃ and placebo group (C); **, P = 0.0031 comparing 25(OH)D₂ and placebo group (C). Note serum 25(OH)D₂ levels less than 4 ng/ml were obtained by subtracting the total 25(OH)D₃ from the total 25(OH)D levels.