A novel vitamin D bioavailability test was employed by Boston Medical Center researchers investigating vitamin D deficiency in Crohn’s patients. Their findings are published online ahead of print in the Journal of Inflammatory Bowel Diseases, the official journal of the Crohn’s and Colitis Foundation of America.
Researchers tested the ability of normal adults and those with inactive Crohn’s disease to absorb vitamin D2; they also looked at the effect of disease location and prior surgery on D2 bioavailability.
The study included 10 normal subjects (50 percent female) and 37 patients with inactive Crohn’s (51 percent female) who had not recently received vitamin D2. After a baseline vitamin D bioavailability test was performed in all subjects, they were each given a single 50,000 IU oral dose of vitamin D2 in a capsule formulation and had their blood drawn 12 hours later to determine serum vitamin D2, which reflected their vitamin D2 absorption capacity.
Results showed 42 percent of Crohn’s patients were vitamin D-deficient(25-hydroxyvitamin D ≤20 ng/mL], while 29 percent were D-insufficient (25(OH)D between 21 and 29 ng/mL). Vitamin D2 levels rose significantly (0.7 ± 0.7 ng/mL (mean ± SEM) to 49.8 ± 3.0 ng/mL ) from baseline 12 hours after supplementation. In the same time frame, , D2 levels increased 0 ng/mL to 34.8 ± 2.8 ng/mL in Crohn’s patients.
Researchers also found a wide variability of vitamin D2 bioavailability in CD patients, who had an average 30-percent decrease in ability to absorb D2 (P=0.01). Analysis of variance (ANOVA) revealed no statistical difference of vitamin D2 bioavailability between patients in the Crohn’s subgroup stratified by the location of disease, the type of surgery, and receiving or not receiving surgery.
The researchers noted more than 70 percent of the patients with quiescent CD were vitamin D-deficient or insufficient. They concluded, “The ability to absorb vitamin D2 in CD patients is unpredictable and the only way to determine this is to perform a vitamin D bioavailability test. Use of this test may guide clinicians in administering the appropriate therapeutic dose of vitamin D for treating vitamin D deficiency in patients with Crohn’s disease.”
January 11, 2011