Boston University School of Medicine researchers have reported that 25-hydroxyvitamin D3 is an effective treatment for vitamin D deficiency for patients with obesity and malabsorption issues. The outcomes from their small randomised clinical trial were outlined in the paper, ‘A pilot-randomized, double-blind crossover trial to evaluate the pharmacokinetics of orally administered 25-hydroxyvitamin D3 and vitamin D3 in healthy adults with differing BMI and in adults with intestinal malabsorption’, The American Journal of Clinical Nutrition.
"This vitamin D metabolite is better absorbed in patients with fat malabsorption syndromes and since it is not as fat soluble, it does not gets diluted in the body fat and is effective in raising and maintaining blood levels of 25-hydroxyvitamin D in obese people," explained corresponding author Dr Michael F Holick, professor of medicine, physiology and biophysics and molecular medicine at Boston University School of Medicine.
In the trial, healthy adults, adults with a fat malabsorption syndrome and adults with obesity were compared to evaluate if a more water-soluble form of vitamin D3 known as 25-hydroxyvitamin D3 was more effective than the same dose of vitamin D3 in improving their vitamin D status.
The randomised, double-blind crossover trial was performed in six malabsorptive patients and ten healthy participants who were given 900 µg of either vitamin D3 or 25(OH)D3 orally followed by a pharmacokinetic study (PKS). After ≥28 d from the first dosing, each participant returned to receive the other form of vitamin D and undergo another PKS. For each PKS, serum vitamin D3 and 25(OH)D3 were measured at baseline and at two, four, six, eight and 12 hours and days one, two, three, seven and 14. Pharmacokinetic parameters were calculated.
Data were expressed as means ± SEMs. The PKS of 900 µg vitamin D3 revealed that malabsorptive patients had 64% lower AUC than healthy participants (1177 ± 425 vs. 3258 ± 496 ng · h/mL; p<0.05). AUCs of 900 µg 25(OH)D3 were not significantly different between the two groups (p=0.540). The ten healthy participants were ranked by BMI and categorized into higher/lower BMI groups (5/group). The PKS of 900 µg vitamin D3 showed that the higher BMI group had 53% lower AUC than the lower BMI group (2089 ± 490 vs. 4427 ± 313 ng · h/mL; p<0.05), whereas AUCs of 900 µg 25(OH)D3 were not significantly different between the two groups (p=0.500).
Compared to healthy adults only about 36 percent of orally ingested vitamin D3 was found in the blood of patients with fat malabsorption syndromes including patients who had gastric bypass surgery. When the same adults ingested 25-hydroxyvitamin D3 the patients with fat malabsorption syndromes were able to absorb it as well as the healthy adults thereby raising their vitamin D status to the same degree. A similar observation was made in the obese subjects compared to the healthy controls.
"Therefore using 25-hydroxyvitamin D3 could be a novel approach for treating vitamin D deficiency in patients with fat malabsorption syndromes and obese adults," added Holick.
This trial was registered at clinicaltrials.gov as NCT03401541.