Randomized controlled trial comparing the bioavailability of vitamin D 3 from fortified Cheddar cheese, fortified low‐fat cheese, and supplement

Objective: We compared the bioavailability of vitamin D3 from novel fortified hard cheeses and from vitamin D3 supplement. Methods: 60 adults were randomly given weekly servings of fortified Cheddar cheese (34 g), fortified low‐fat cheese (41 g), or vitamin D 3 supplement. These contained 28,000 IU vitamin D 3 , equivalent to 4,000 IU/d. 20 adults were also randomized to placebo. Bioavailability of vitamin D 3 was assessed by comparing the serum 25‐hydroxyvitamin D [25(OH)D] response over 8 weeks. Results: In the placebo group, initial 25(OH)D, 55.0 ± 25.3 nmol/L (mean ± SD), declined over the 8‐wk winter protocol, to 50.7 ± 24.2 nmol/L (paired t test, p=0.046). In the vitamin D 3 ‐treated groups, the mean increases in 25(OH)D from baseline to 8 wk were: 65.3 ± 24.1 nmol/L (Cheddar cheese), 69.4 ± 21.7 (low‐fat cheese), 59.3 ± 23.3 (supplement with food), and 59.3 ± 19.6 (supplement without food); these changes were significantly different from the placebo group (ANOVA, p<0.0001) but not from one another (ANOVA, p=0.62). Compared with baseline, serum parathyroid hormone decreased significantly with both the fortification (paired t test, p=0.003) and the supplementation (paired t test, p=0.012) strategies. Conclusions: Vitamin D 3 is equally bioavailable from fortified hard cheeses and from supplement. Therefore, hard cheese is a viable food for vitamin D fortification, and can help to enhance vitamin D status.