This is a 6-month cross-over trial of vitamin D supplementation in 38 healthy men and women aged 18 years and older. The primary aim is to compare the change in serum 25(OH)D concentration following vitamin D supplementation with chewable tablets versus pills. Secondary aims are to evaluate satisfaction and adherence to the vitamin D chewable tablet supplement. Questionnaires on physical activity, sunlight exposure and dairy product consumption will be administered to adjust for confounding factors. A questionnaire will be administered to assess satisfaction and pill count to evaluate adherence to treatment. This research intends to test the hypothesis that the vitamin D chewable tablet supplement is as effective as a traditional vitamin D pill supplement to increase serum 25(OH)D concentrations.

Inclusion Criteria:

• Caucasian men and women;
• Aged 18 years and older;
• Having a serum 25(OH)D concentration of 75 nmol/L or less.

Exclusion Criteria:

• Regular consumption of a supplement containing > 400 IU/d of vitamin D over the last 2 months;
• Intestinal malabsorption;
• Cirrhosis;
• Renal insufficiency (creatinine clearance <60 ml/min);
• Hypercalcemia;
• Pregnancy;
• Breastfeeding;
• Inability to provide informed consent.