There is growing evidence for the positive effects of vitamin D in reducing risk from disease and all cause mortality. This has increased our awareness of the need for evidence-based strategies to redress the high prevalence of low vitamin D status in the UK. We have just completed a 48-month FSA-funded study (known as the D-FINES study) in which we show that South Asian women were vitamin D deficient for the entire year and Caucasian women were below 50 nmol/l during the winter months (1). In a parallel study in Aberdeen, post-menopausal Caucasian Scottish women had a 10 nmol/l lower 25OHD status in comparison with post-menopausal Caucasian women living in Southern England (2). While food fortification is a sustainable solution for the prevention of vitamin D deficiency, the Food Industry needs to determine the most effective means of carriage, optimal concentration and chemical form of vitamin D if it is to maximise the effectiveness of fortification. The aim of this study was to undertake a meta-analysis of vitamin D2v. vitamin D3 RCTs in raising 25-hydroxyvitamin D status.
The literature search for the meta-analysis used the ISI Web of Knowledge using terms: ‘vitamin D2 and D3’ or ‘ergocalciferol and cholecalciferol’; ‘supplementation’ and ‘25 hydroxyvitamin D’. The Inclusion criteria was: (1) healthy adults, male or female; (2) study compared D2 and D3 in various vehicles; (3) outcome measure serum 25(OH)D; (4) intervention trials (one exception) nine studies included: eight intervention trials and one observational total subjects: n 919; age: 18–97 years; supplement dose: 1000–4000 IU/d for 14 d 3 months; or 50 000–300 000 IU bolus; oral and im. As shown below, six out of the eight RCT found the change in 25HOD status was greater in the vitamin D3 form in comparison with the vitamin D2 form.
The published studies were: Armas (2004) J Clin End Metab 89, 5387–5391: D2<D3; Biancuzzo (2010) Am J Clin Nutr 91, 1621–1626: No diff; Glendenning (2009) Bone 45, 870–875: D2<D3; Holick (2008) J Clin End Metab 93, 677–681: No diff; Leventis (2009) Scand J Rheumatol 38, 149–153: D2<D3; Romagnoli (2008) J Clin End Metab 93, 3015–3020: D2<D3; Tjellessen (1986) Bone Miner 1, 407–413: D2<D3; Trang (1998) Am J Clin Nutr 68, 854–8: D2<D3. All studies (except two) found 25OHD change higher with vitamin D3.
These results are further confirmed in the Forest Plots as shown in Fig. 1. Further analysis of the meta-analysis data is currently underway but these data suggest that vitamin D3 is a superior form of vitamin D for raising 25HOD status.