Vitamin D₂ vs. vitamin D₃: They are not one and the same

Abstract

Abstract Conflicting evidence has led to uncertainty as to whether vitamin D 2 and vitamin D 3 are equally efficacious in improving vitamin D status, despite historically being considered equipotent. A systematic review and meta‐analysis completed in 2012 indicated that D 3 was more effective at raising vitamin D levels {using total 25‐hydroxyvitamin D [25(OH)D] as a marker of status} but the meta‐analysis identified high levels of heterogeneity between studies and a lack of statistically powered sample sizes to provide a conclusive answer. Thus, to meet the need for robust data, our research team conducted the largest (to date) randomised, controlled trial comparing the two forms of vitamin D. The D 2 –D 3 Study was conducted in 335 healthy South Asian ( n = 90) and White European women ( n = 245). The study was designed to compare the respective efficacy of vitamin D 2 with vitamin D 3 at raising total 25(OH)D when added to a juice or a biscuit, at a relatively low dose of 15 μg/day for 12 weeks. Overall, the results showed that those who consumed vitamin D 3 showed an average increase in vitamin D status of 74%–75%, whereas an average increase of 33%–34% in vitamin D status was found in those who consumed vitamin D 2 . Therefore, this study emphatically shows that vitamin D 3 is more than twice as effective as vitamin D 2 at raising total 25(OH)D concentrations, when given in a low dose that is both physiologically relevant and in line with public health guidance.