Researchers compared the bioavailability of vitamin D2 and vitamin D3 from orange juice with that from vitamin D2 and vitamin D3 supplements. A secondary aim was to determine which form of vitamin D is more bioavailable in orange juice.

 

This randomized, placebo-controlled, double-blind study was conducted in healthy adults aged 18–84 (15–20/group) who received 1000 IU vitamin D3, 1000 IU vitamin D2 or placebo in orange juice or capsule for 11 weeks at the end of winter.

 

According to results, 64% of subjects began the study deficient in vitamin D (i.e., 25-hydroxyvitamin D [25(OH)D]) concentrations <20 ng/mL). Analysis of the area under the curve showed no significant difference in serum 25(OH)D between subjects who consumed vitamin D–fortified orange juice and those who consumed vitamin D supplements. No significant difference in serum 25(OH)D3 was observed between subjects who consumed vitamin D3–fortified orange juice and vitamin D3 capsules. Similarly, no significant difference in serum 25(OH)D2 was observed between subjects who consumed vitamin D2–fortified orange juice and vitamin D2 capsules. No significant overall difference in parathyroid hormone concentrations was observed between the groups.