Abstract
OBJECTIVES: The absorption of conventional cholecalciferol may be impaired in patients with inflammatory bowel disease (IBD). The bioavailability and optimal dosing of buccally absorbable nanoemulsion vitamin D in this population remain unclear. This study aimed to compare the effects of buccal nanoemulsion and conventional oral vitamin D supplementation on serum 25-hydroxyvitamin D (25OHD) levels in patients with IBD. METHODS: This was an open-label randomized trial. Patients with IBD were assigned to receive cholecalciferol in an oil emulsion at a dose of 14 000 IU weekly (GTTS) and orally absorbed cholecalciferol at dose 4000 IU twice a week (SPRAY) for 12-16 weeks during the winter months. Plasma 25OHD levels were measured at baseline and after the supplementation period. RESULTS: A total of 120 patients were analyzed. Among 75 subjects with CD and 45 with UC, 27% had active disease, and 24% of the Crohn's disease patients had undergone ileocecal resection. The initial mean 25OHD level was 65.9 ± 21.0 nmol/l in the SPRAY group and 59.1 ± 27.7 nmol/l in the GTTS group. A similar increase of 9.3 ± 26.8 nmol/l (GTTS) and 9.2 ± 27.7 nmol/l (SPRAY) in 25OHD levels occurred in both groups, with similar variations. The proportion of subjects with normal and sub-normal levels following the substitution was comparable. The change in 25OHD level correlated negatively only with the baseline 25OHD level (p < 0.02) among all monitored variables. CONCLUSION: In IBD patients, the sufficient supplementation dose of the orally absorbable cholecalciferol is half that of the conventional oil emulsion (1143 IU/day vs. 2000 IU/day). Variable intestinal absorption is not a factor explaining inter-individual differences in 25OHD levels using a conventional vitamin D emulsion.