Vitamin D-2 is as effective as vitamin D-3 in maintaining circulating concentrations of 25-hydroxyvitamin D
ABSTRACT Two reports suggested that vitamin D2 is less effective than vitamin D3 in maintaining vitamin D status.
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.
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.
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.
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.
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ABSTRACT: The electrochemical behavior of vitamins D-2 and D-3 were examined by performing cyclic voltammetry (CV), rotating disk electrode voltammetry, controlled potential electrolysis and chemical oxidation in aprotic organic solvents. Both vitamins were electrochemically oxidized in dichloromethane and acetonitrile (E-p(ox) similar to +0.8 vs. (Fc/Fc(+))/V, where E-p(ox) is the anodic peak potential and Fc = ferrocene) via a one-electron chemically irreversible process on the short voltammetric time scale (<= seconds). Varying the scan rate (0.1 V s(-1) to 20 V s(-1)) and temperature (233 K to 293 K) did not strongly affect the voltammetric response recorded on platinum and glassy carbon electrode surfaces with the oxidation process remaining chemically irreversible over the range of scan rates and temperatures tested, indicating that the initially formed cation radical was not long-lived. Repetitive CV experiments indicated that the oxidized product partially adsorbed onto the electrode surface, resulting in diminishing peak currents with multiple scans. Bulk controlled potential electrolysis of the vitamin D compounds performed by alternating several cycles of oxidative electrolysis and reductive pulsed stripping proved to be effective in stripping the adsorbed species off the electrode surfaces. Longer time scale bulk electrolysis experiments led to the detection of a new oxidation peak appearing at less positive potentials as the electrolysis progressed, suggesting that the compounds underwent oxidation on long time scales (minutes to hours) via a two electron process. The vitamins were most likely initially oxidized via one-electron (E-step) to form a cation radical, which reacts homogeneously in two chemical steps (C-steps) where one chemical step is fast (< 1 s) and one is relatively slow (> 1 s). On the electrolysis timescale, the oxidized product then undergoes a second electron transfer (E) at less positive potentials, so the overall mechanism is an ECCE process. Chemical oxidation of vitamin D-3 with 2 mol equiv of the one-electron oxidant, NO+SbF6- in acetonitrile/dichloromethane 1:4 ratio (v/v) resulted in the complete oxidation of the starting material in an overall two-electron process, with NMR analysis of the reaction mixture indicating that the triene moiety is absent from the products.Electrochimica Acta 08/2014; 138:400-409. DOI:10.1016/j.electacta.2014.06.133 · 4.09 Impact Factor
Journal of Medical Biochemistry 01/2013; 32(1):1-58. DOI:10.2478/v10011-012-0025-y · 1.08 Impact Factor
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ABSTRACT: A single-run high performance liquid chromatography (HPLC) with diode array detector (DAD) based method was developed for the separation, identification and comprehensive quantification of degradation products of ergosterol formed in oyster mushroom (Pleurotus ostreatus) after UV-B exposure. After 60 min, 10 substances involved in the photoprocess were separated, identified by their characteristic DAD spectrum and distinguished by their molecular weight, in cases where spectra were identical: vitamin D-2, previtamin D-2, tachysterol(2), lumisterol(2) and ergosterol, and, in minor quantity, their structural analogues of the 22,23-dihydroergocalciferol (vitamin D-4) series. Sample preparation protocol affected the total yields and the ratios of previtamin and vitamin D-2/D-4. Hot alkaline hydrolysis resulted in the best digestion of the mushroom matrix and accordingly gave the highest vitamin D yield (D-2: 141.32 mu g g(-1) dry matter, DM; D-4: 22.72 mu g g(-1) DM). Limit of detection for vitamin D-2/4 was 0.02 mu g g(-1) dry matter (DM) and was estimated for previtamin D-2/4 (0.06 mu g g(-1) DM), tachysterol(2/4) (0.02 mu g g(-1) DM) and lumisterol(2/4) (0.06 mu g g(-1) DM). Recovery of spiked vitamin D-2 was 97 +/- 0.7%. The study provides an analytical tool to assess the process of vitamin D generation after UV-B treatment for the production of oyster mushrooms with a balanced nutritional profile of vitamin D compounds.Journal of Food Composition and Analysis 09/2013; 31(2):266-274. DOI:10.1016/j.jfca.2013.05.017 · 2.26 Impact Factor