Vitamin D – the big D-bate

Abstract

In this issue of our journal we have invited a number of experts to comment on the recommended levels of intake of vitamin D (1)(2)(3)(4)(5)(6)(7)(8)(9) . This invitation is done in order to shed some light on the ongoing debate regarding the increased recommended level of intake of vitamin D from the Institute of Medicine North America (10) . Our Associate Editor Oliver Gillie has also written his own editorial in the area (11) .The journal finds this debate of great importance, not only as a part of a sound scientific debate in general but also with regard to the intriguing nature of vitamin D and the wealth of factors that influence our vitamin D status. Environmental factors, clothing, seasonal factors, skin colour and intake all have an influence on vitamin D status: the delicate balance between them provides a challenging perspective for public health nutritionists. A recent study of children in Iran revealed a substantial proportion (32?9 %) of children aged 15-23 months with vitamin D at insufficiency levels (12) , significantly more among girls. Iran has a system for encouraging supplementation but the level of compliance is uncertain. This is just one example out of many, showing the need for comprehensive work in this area towards a common consensus on needs, intake, formation and uptake of vitamin D, followed up by policy and action.Clearly, this is a research field which not only intrigues us but also one that encourages debate. We heartily welcome more debate on vitamin D as a nutritional issue and also as an overall health issue in relation to environment, shading, skin cancer risk and pollution, as well as outdoor play and activities. We look forward to receiving your views and suggestions.

Predictors of vitamin D status in subjects that consume a vitamin D supplement

“…Baseline characteristics of summer and winter subjects were compared using the Mann-Whitney U test for continuous data or by the chi-square test for categorical data as appropriate. For multivariate regression, serum concentrations of 25(OH)D for both summer and winter were not normally distributed and were log (10) transformed prior to analysis. To facilitate meaningful comparisons of predictor variables, standardized β-coefficient estimates are presented for the regression analysis.…”

“…7 This level is based on the criteria that it will meet the bone health requirements of 97.5% of the population and maintain circulating levels of 25-hydroxy-vitamin D (25(OH)D) at 450 nmol/l. 7 However, optimal levels of vitamin D are in dispute, [8][9][10] and a substantial body of evidence indicates that serum levels 475 nmol/l are conducive to multiple health benefits beyond bone health (for an overview, see Holick 11 ). Indeed, since the release of the IOM report in 2011, the Endocrine Society has released guidelines stating that vitamin D deficiency is defined as serum 25(OH)D levels o 50 nmol/l, vitamin D insufficiency as levels o 75 nmol/l and levels above 75 nmol/l as sufficient.…”

Reproducibility of Serum 25-Hydroxyvitamin D and Vitamin D-Binding Protein Levels Over Time in a Prospective Cohort Study of Black and White Adults

“…Measures of agreement were calculated for the entire sample as well as by race. Using recent, though still debated (20)(21)(22)(23)(24)(25), guidelines proposed by the Institute of Medicine (20), vitamin D status was categorized as deficient (<12 ng/mL 25(OH)D), inadequate (12-19.9 ng/mL), or adequate (≥20 ng/mL). Weighted kappa coefficients, calculated with Fleiss-Cohen weights, were used to compare the levels of agreement for categorical assignment between baseline and repeat samples (26).…”

Calcium and vitamin D for chronic disease: a time for action

“…However, a recent influential report by the Institute of Medicine of the National Academies has advocated calcium and vitamin D only for bone and musculoskeletal health (Institute of Medicine, 2010). The fallout from such a decision resonates in the detail of many invited opinions on this research document (Yngve et al, 2011).…”