Be sure your doctor prescribes vitamin D3 rather than vitamin D2:hyien wrote:Doc will be prescribing me some supps, not sure what yet.
I live in the tropics, kind of surprising I have a vit D deficiency.
Vitamin D2 is much less effective than vitamin D3 in humans. (2004)
Laura A. G. Armas, Bruce W Hollis, and Robert P Heaney
Full Text (5 pages): http://press.endocrine.org/doi/pdf/10.1210/jc.2004-0360
Vitamins D(2) and D(3) are generally considered to be equivalent in humans. Nevertheless, physicians commonly report equivocal responses to seemingly large doses of the only high-dose calciferol (vitamin D(2)) available in the U.S. market. The relative potencies of vitamins D(2) and D(3) were evaluated by administering single doses of 50,000 IU of the respective calciferols to 20 healthy male volunteers, following the time course of serum vitamin D and 25-hydroxyvitamin D (25OHD) over a period of 28 d and measuring the area under the curve of the rise in 25OHD above baseline. The two calciferols produced similar rises in serum concentration of the administered vitamin, indicating equivalent absorption. Both produced similar initial rises in serum 25OHD over the first 3 d, but 25OHD continued to rise in the D(3)-treated subjects, peaking at 14 d, whereas serum 25OHD fell rapidly in the D(2)-treated subjects and was not different from baseline at 14 d. Area under the curve (AUC) to d 28 was 60.2 ng.d/ml (150.5 nmol.d/liter) for vitamin D(2) and 204.7 (511.8) for vitamin D(3) (P < 0.002). Calculated AUC(infinity) indicated an even greater differential, with the relative potencies for D(3):D(2) being 9.5:1. Vitamin D(2) potency is less than one third that of vitamin D(3). Physicians resorting to use of vitamin D(2) should be aware of its markedly lower potency and shorter duration of action relative to vitamin D(3).
Vitamin D3 Is More Potent than Vitamin D2 in Humans (2010)
JCEM (Journal of Clinical Endocrinology & Metabolism)
"Conclusion:D3 is approximately 87% more potent in raising and maintaining serum 25(OH)D concentrations and produces 2- to 3-fold greater storage of vitamin D than does equimolar D2. For neither was there evidence of sequestration in fat, as had been postulated for doses in this range. Given its greater potency and lower cost, D3 should be the preferred treatment option when correcting vitamin D deficiency."
The case against ergocalciferol (vitamin D2) as a vitamin supplement (2006)
Lisa Houghton and Reinhold Vieth