Bioavailability of vitamin D(2) and D(3) in healthy volunteers, a randomized placebo-controlled trial.
What this study found
Vitamin D3 was more effective than vitamin D2 at raising total 25(OH)D. In the vitamin D3 group, total 25(OH)D increased from 43.7 ± 23.3 to 89.2 ± 22.1 nmol/L and 25(OH)D3 increased from 41.5 ± 22.8 to 88.0 ± 22.1 nmol/L after 8 weeks. In the vitamin D2 group, total 25(OH)D increased from 37.6 ± 13.3 to 67.8 ± 20.1 nmol/L, but 25(OH)D3 fell from 36.4 ± 13.3 to 16.6 ± 6.3 nmol/L while 25(OH)D2 rose to 51.2 ± 18.5 nmol/L. Between-group differences were significant (ANOVA P = .001), no adverse effects were reported, and serum calcium remained within the normal range. These findings support…
- Study & population
- Randomized, placebo-controlled, parallel-group trial in healthy adult volunteers in Halle (Saale), Germany, conducted during winter (January to March 2012) when UVB exposure was minimal.
- Intervention
- Participants received one oral tablet daily for 8 weeks containing either vitamin D2 (ergocalciferol) 50 µg/d or vitamin D3 (cholecalciferol) 50 µg/d (2000 IU/d), versus placebo in the parent trial.
- Key limitation
- The trial was short (8 weeks), single-center, and conducted in healthy adults during one winter season, which limits generalizability.
View source
Open PDFOriginal abstract
BACKGROUND The bioequivalence of the different forms of vitamin D, ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3), has been questioned. Earlier studies have suggested that vitamin D2 is less biologically active than vitamin D3. OBJECTIVE AND DESIGN In a parallel study, we tested the effects of supplementation with 50-μg/d doses of vitamin D2 or D3 or a placebo over a period of 8 weeks on 25(OH)D2, 25(OH)D3, their sum 25(OH)D (primary outcome variables), and PTH in healthy volunteers applying a double-blind, randomized study design. The study was conducted during the winter of 2012 in Halle (Saale), Germany, at latitude 51°47N, when UVB irradiation is virtually absent. Blood samples for the determinations of vitamin D status and PTH were collected at baseline and after 4 and 8 weeks of supplementation. RESULTS In the placebo group (n = 19), 25(OH)D3 decreased from 39.4 ± 14.2 to 31.1 ± 12.4 nmol/L after 8 weeks (P < .01). In the vitamin D3 group (n = 42), the concentrations of 25(OH)D3 increased from 41.5 ± 22.8 nmol/L at baseline to 88.0 ± 22.1 nmol/L after 8 weeks (P < .01). In the group receiving vitamin D2 (n = 46), the 25(OH)D2 concentrations increased significantly, whereas the 25(OH)D3 concentration fell from 36.4 ± 13.3 nmol/L at baseline to 16.6 ± 6.3 nmol/L after 8 weeks (P < .01). The total 25(OH)D was not different between the groups at baseline but differed significantly between the groups after 4 and 8 weeks (P < .001). CONCLUSIONS Vitamin D3 increases the total 25(OH)D concentration more than vitamin D2. Vitamin D2 supplementation was associated with a decrease in 25(OH)D3, which can explain the different effect on total 25(OH)D.