Donald Brown, ND

Dr. Brown reports he is a retained consultant for Nature’s Way.

Source: Oliveri B, et al. Vitamin D3 seems more appropriate than D2 to sustain adequate levels of 25OHD: A pharmacokinetic approach. Eur J Clin Nutr 2015;doi:10.1038/ejcn.2015.16. [Epub ahead of print].

Summary Points

  • Compared to vitamin D2, daily supplementation with vitamin D3 appears to sustain serum 25(OH)D levels even after discontinuation of supplementation in healthy adults.

± 2.0 mcg/day; 3.4 ± 2.0 mcg/d in the D3 group; and 4.3 ± 2.0 mcg/d in the D2 group). Fifteen subjects presented with 25(OH)D levels < 20 ng/mL and another 15 with levels 20-30 ng/dL. Only three subjects had 25(OH)D levels 30 ng/dL. After the loading dose of 100,000 IU, the 25(OH)D levels of both vitamin D groups had a rapid and similar rise that persisted to day 7 (D2, 36.6 ± 11.0 ng/mL; D3, 41.0 ± 4.9 ng/mL). The geometric mean of Cmax was analyzed during the course of the study and the area under the curve (AUC) was for days 7 to 77 (based on the equivalent 25(OH)D levels in the vitamin D groups after the loading dose). The D3 AUC was 28.6% higher than the D2 AUC and both vitamin D groups were statistically significantly higher than placebo (P < 0.04 for D3 and P < 0.01 for D2). At day 77 (after 56 days of no supplementation), 25(OH)D levels in the D2 group were significantly lower compared to the D3 group (23.6 ng/mL vs 33.4 ng/mL, P < 0.04) and closer to those for the placebo group (22.5 ng/mL). Taking into account the presence of vitamin D independent of the loading dose, it was estimated that the elimination half-lives were 33 days of D2 and 82 days for D3. There were no reported treatment-related adverse events and no subject had hypercalciuria or hypercalcemia.

1 Finally, the results support the conclusions of a 2012 meta-analysis that showed a higher response to D3 compared to D2 in terms of increase and maintenance of 25(OH)D levels.2

  1. Am J Clin Nutr 2003;77:204-210.
  2. Am J Clin Nutr 2012;95:1357-1364.