expert opinion

Vitamin D deficiency is rampant in Europe

April 1, 2016

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Kevin Cashman, Professor of Food and Health, School of Food & Nutritional Sciences, University College Cork, Ireland

Professor Kevin Cashman of the School of Food & Nutritional Sciences, University College Cork, Ireland, whose main area of research interests concerns the public health implications of vitamin D intake, including population distributions of serum 25(OH)D and related metabolites, dietary requirements for vitamin D in different population subgroups, food-based solutions for increasing vitamin D intake and status, and the role of vitamin D in health outcomes, has over 130 publications.

Professor Cashman is the joint coordinator (together with Dr. Mairead Kiely) of a major European Commission-funded project entitled “Food-based solutions for optimal vitamin D nutrition and health through the life cycle” (ODIN), which is a 31-partner collaborative project aimed at tackling vitamin D deficiency in Europe (2013–2017).

A new paper issued by the ODIN project collaborators (1) provides evidence that there is a pandemic of vitamin D deficiency in Europe. The Vitamin D Standardization Program (VDSP) was applied retrospectively to 14 European studies and added to the data of four newer studies that had used the VDSP protocol from the start, providing a total cohort of 55,844 European individuals. Using the very strict definition of vitamin D deficiency as a serum concentration of less than 30 nmol/L 25(OH)D, an annual average of 13% of Europeans were deficient. This value rose to 17.7% in the winter months and fell to 8.3% in the summer. However, when the more usual definition of deficiency of less than 50 nmol/L was applied, the average annual level of prevalence rose to an astounding 40.4%!

It was also found that dark-skinned ethnic subgroups had much higher levels of vitamin D deficiency than their white-skinned counterparts. The prevalence of serum 25(OH)D levels of less than 30 nmol/L was between 3 and 71 fold higher in the dark-skinned subgroups. Curiously, even accounting for ethnicity, the prevalence of vitamin D deficiency in mid-latitude European countries such as the UK, Ireland and the Netherlands was found to be higher than the sun-deprived northern latitude countries such as Norway, Iceland or Finland. The authors concluded their paper with the comment that “vitamin D deficiency is evident throughout the European population at prevalence rates that are a matter of concern and require action both from a public health and clinical perspective”.

Professor Cashman has found that despite new, revised intake recommendations advice in Europe, it seems that the contribution to vitamin D status from consumption of supplements remains low (3). Whilst the biofortification of food products could make a useful contribution to addressing vitamin D deficiency, the development of new vitamin D-fortified dairy products may not be the sole answer to vitamin D deficiency among sun-deprived individuals (4).

A recent study (5) compared the effects of vitamin D2 and vitamin D3 consumed as a supplement and as an ingredient in bread by young Finnish women for eight weeks with regard to increasing serum 25(OH)D levels. It found that vitamin D2 generated from UV-irradiated yeast in bread was not bioavailable to humans and that vitamin D2 supplements were less successful than vitamin D3 supplements in raising serum 25(OH)D levels.

It has been shown in a study of a cohort of 957 adults aged 60 years or more (6) from Northern Ireland that low levels of serum 25-hydroxyvitamin D are associated with higher levels of markers of inflammation (serum cytokines IL-6, IL-10, TNF-α and C-reactive protein).

References

  1. Cashman KD, Dowling KG, Gonzalez-Gross M et al.; “Vitamin D deficiency in Europe: pandemic? “; American Journal of Clinical Nutrition 2016, 1–6. doi.org/10.3945/ajcn.115.120873.
  2. Harrison-Dunn AR; “First EU-wide data offers “firm evidence” of Vitamin D deficiency”; www.nutraingredients.com, 8th March 2016.
  3. Cashman KD; “Vitamin D:dietary requirements and food fortification as a means of helping achieve adequate vitamin D status”; J Steroid Biochem Mol Biol 2015; 148: 19-26.
  4. Cashman KD & Kiely M; “Tackling inadequate vitamin D intakes with the population of dairy products with Vitamin D may not be enough”; Endocrine 2016; 51(1); 38-46.
  5. Itkonen ST, Skaffari E, Saaristo P et al.; “Effects of vitamin D2-fortified bread v. supplementation with vitamin D2 or D3 on serum 25-hydroxyvitamin D metabolites: an 8-week randomised-controlled trial in young adult Finnish women”; British Journal of Nutrition 2016, 25, 1–8. doi.org/10.1017/S0007114516000192
  6. Laird E, McNulty H, Ward, M.et al.; “Vitamin D Deficiency Is Associated With Inflammation in Older Irish Adults”; The Journal of Clinical Endocrinology & Metabolism 2014, 99(5), 1807–1815.doi.org/10.1210/jc.2013-3507