12 January - 20 June 2016

Are vitamin D2 and vitamin D3 as effective as each other at increasing vitamin D status?

It has always been suggested that vitamin D2 and vitamin D3 are equally as effective at increasing levels of vitamin D in the blood. A study published in the American Journal of Clinical Nutrition has investigated this thinking using a food fortification intervention model.

It has always been suggested that vitamin D2 and vitamin D3 are equally as effective at increasing levels of vitamin D in the blood.  A study published in the American Journal of Clinical Nutrition has investigated this thinking using a food fortification intervention model.  The 12-week double-blind, randomised, placebo controlled, parallel food fortification study, led by scientists from University of Surrey compared the efficacy of 15 µg vitamin D2 and vitamin D3 in increasing serum total 25(OH)D in South Asian and white European women during two winters in the UK. 

Tripkovic et al. recruited 335 healthy participants aged 20-64 years old and split them into 5 treatment groups: a placebo drink and biscuit group, juice supplemented with 15 µg vitamin D2 with placebo biscuit, placebo juice with biscuit supplemented with 15 µg vitamin D2, juice supplemented with 15 µg vitamin D3 with placebo biscuit and placebo juice with biscuit supplemented with 15 µg vitamin D3.  At baseline, at week 6 and at 12 weeks the participants attended a clinical investigation unit where the scientists took fasting blood samples and measured 25-hydroxyvitamin D3, calcium, albumin, and parathyroid hormone.  Also at baseline and at the end of the intervention period the participants were asked to complete a 4-day diary on dietary intake.  Using a dosimeter, the scientists measured the participants UV exposure for 7 days. 

Tripkovic et al. found that the placebo group experienced a 25% reduction in total 25(OH)D over the intervention period (from approx. 44.8 nmol/L to 33.5 nmol/L).  Both vitamin D2 fortification products were found to increase total 25(OH)D, when data was combined for the 2 ethnicity groups, by 33% for the group receiving the D2 fortified juice and placebo biscuit and by 34% for the placebo juice and fortified biscuit group.  However, the vitamin D3 products were found to increase total 25(OH)D, by 75% for those receiving the supplement juice and by 74% for those receiving the supplement biscuit.  Whilst the team did not find any significant changes between the two ethnic groups, they did report that “the South Asian women appeared to have a greater response to the vitamin D (both vitamin D2 and D3) than the white European women, likely due to their lower 25 (OH)D status at baseline.”   In the vitamin D2 group the South Asian women who took the vitamin D2 did not meet 50 nmol/L at the end of the trial whilst those in the vitamin D3 juice group met recommendations.   All white European who consumed either the vitamin D3 biscuit or D3 juice “achieved serum 25(OH)D concentrations >50 nmol/L at the end of intervention.”  In the vitamin D2 supplemented biscuit group 90% met these levels and in the vitamin D2 supplemented juice group 89% met these levels. 

The authors discuss their findings and suggest the differences in the efficacy of vitamin D2 and vitamin D3 could be “focused around the effect of vitamin D2 on 25(OH)D3 which indicates a possible mechanism that encompasses competitive binding affinity between vitamin D2 and D3 with the vitamin D-binding protein and hydroxylation enzymes.”  They also suggest that 25(OD)D2 has a “shorter half-life” compared to 25(OH)D3 suggesting “that the elimination or degradation of 25(OH)D is another mechanism that explains the differences in efficacy”.  The study concludes by reiterating its findings and noting that both forms of vitamin D are effective in fortified foods for raising total 25(OH)D.

RSSL provides vitamin analysis in a wide range of matrices including drinks, fortified foods, pre-mixes and multi-vitamin tablets, including the analysis for Vitamin D2 and Vitamin D3.  For more information please contact Customer Services on +44 (0) 118 918 4076 or email enquiries@rssl.com

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