Towards prevention of vitamin D deficiency and beyond: Knowledge gaps and research needs in vitamin D nutrition and public health

Vitamin D Research Group, School of Food and Nutritional Sciences, University College Cork, Republic of Ireland.
The British journal of nutrition (Impact Factor: 3.45). 12/2011; 106(11):1617-27. DOI: 10.1017/S0007114511004995
Source: PubMed


The North American Institute of Medicine (IOM) recently published their report on dietary reference intakes (DRI) for Ca and vitamin D. The DRI committee's deliberations underpinning this most comprehensive report on vitamin D nutrition to date benefited hugely from a much expanded knowledge base in vitamin D over the last decade or more. However, since their release, the vitamin D DRI have been the subject of intense controversy, which is largely due to the persistence of fundamental knowledge gaps in vitamin D. These can be identified at the levels of exposure, metabolism, storage, status, dose-response, function and beneficial or adverse health effects, as well as safe and effective application of intake recommendations at the population level through sustainable food-based approaches. The present review provides a brief overview of the approach used by the IOM committee to revise the DRI for vitamin D and to collate from a number of authoritative sources key knowledge gaps in vitamin D nutrition from the public health perspective. A number of research topics are outlined and data requirements within these are identified and mapped to the risk assessment framework used by the DRI committee. While not intended as an exhaustive list, it provides a basis for organising and prioritising research efforts in the area of vitamin D, which may offer a perspective on the major areas in need of attention. It is intended to be of use to researchers, national policy makers, the public health community, industry groups and other relevant stakeholders including funding institutions.

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    • "Serum 25(OH)D 3 concentrations were also determined in 542 adults in the 1980s [18]. As noted recently by Cashman and Kiely [2], there is an ongoing need to assess vitamin D status in representative populations within Europe. Because of the paucity of Belgian data, the present research based on data collected from the Nutrition, Environment and Cardio-Vascular Health (NESCaV) cross-sectional survey was conducted to assess the vitamin D status in the general population of the province of Liège (Wallonia, Belgium) and to identify its potential determinants and relationship with vitamin D supplementation. "
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    ABSTRACT: Data on the vitamin D status of the population of Wallonia (Belgium, 51°30' North) are scarce. This study was carried out to estimate vitamin D deficiency, identify potential determinants, and analyze their relationship with vitamin D supplementation. We tested the hypothesis that vitamin D deficiency is common in the general population, particularly among subjects without supplementation. Vitamin D deficiency was defined as a serum level of 25-hydroxyvitamin D (25(OH)D) concentration less than 50nmol/L. Data were analyzed from 915 participants of the Nutrition, Environment and Cardio-Vascular Health cross-sectional survey. The median (interquartile range) 25(OH)D level was 53.1 (37.8-69.9) nmol/L, and 44.7% of the subjects were vitamin D deficient. Subjects without vitamin D supplementation were more concerned by vitamin D deficiency than those with supplementation (odds ratio [OR], 3.35; P < .0001). From a multivariate standpoint, the potential determinants of vitamin D deficiency among subjects without vitamin D supplementation were season, specifically spring and winter (OR, 7.36 and 6.44, respectively), obesity (OR, 2.19), low household income (OR, 1.73), and lack of solarium use (OR, 1.79). For subjects with supplementation, the only determinant observed for vitamin D deficiency was obesity (OR, 5.00). This work evidenced the high prevalence of 25(OH)D deficiency in the general population, especially among nonsupplemented subjects with obesity, low household income, and/or lack of light. Vitamin D supplementation looks effective in our population, especially via a stabilization of vitamin D coverage throughout the seasons. The best dietary strategy to achieve optimal 25(OH)D concentrations all year round in the general population requires more research. Copyright © 2015. Published by Elsevier Inc.
    Nutrition research 06/2015; 35(8). DOI:10.1016/j.nutres.2015.06.005 · 2.47 Impact Factor
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    ABSTRACT: Despite interest and expanding research on non-bone health outcomes, the evidence remains inconclusive concerning the causal role of vitamin D in the non-bone health outcomes. To improve our understanding of its role, research needs to address five key areas related to vitamin D: 1) its physiology and molecular pathways. 2) its relationship to health outcomes. 3) its exposure-response relationships, 4) its interactions with genotype and other nutrients and 5) its adverse effects. Its metabolism needs to be elucidated including extra-renal activation and catabolism, distribution and mobilization from body pools, kinetics of this distribution, and their regulation during pregnancy and lactation. Rigorous, well-designed randomized clinical trials need to evaluate the causal role of vitamin D in a diverse array of non-bone health and chronic disease outcomes across the life cycle and reproductive states. Critically needed is the determination of the exposure-response, inflection and threshold of serum 25(OH)D concentrations relative to functional and health outcomes. The dose-response relationships of standardized measures of serum 25(OH)D need to be understood in response to low and high doses of total vitamin D with careful consideration of confounding factors including catabolic rates. How do relevant genetic polymorphisms, dietary calcium and phosphate and potentially dietary cholesterol interact with vitamin D exposure on its bioavailability, transport, distribution in body pools, metabolism and action as well as on bone and non-bone health outcomes? The nature and mechanisms of U-shaped risk relationships with adverse health outcomes at higher exposure to vitamin D needs elucidated across the life cycle and reproductive stages.
    Scandinavian journal of clinical and laboratory investigation. Supplementum 04/2012; 243:154-62. DOI:10.3109/00365513.2012.682895
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    ABSTRACT: The many recently published data on vitamin D have raised much interest in the medical community. One of the consequences has been a great increase in the prescription of vitamin D concentration measurements in clinical practice. It must be reminded that only the measurement of 25-hydroxyvitamin D (25(OH)D) concentration is indicated to evaluate vitamin D status. Furthermore, since vitamin D insufficiency is so common, since treatment is inexpensive and has a large safety margin, and since we already have much data suggesting that besides its classic effects on bone and mineral metabolism, vitamin D may potentially be helpful for the prevention/management of several diseases, perhaps should it be prescribed to everyone without prior testing? In our opinion, there are however groups of patients in whom estimation of vitamin D status is legitimate and may be recommended. This includes patients in whom a "reasonably" evidence-based target concentration (i.e., based on randomized clinical trials when possible) should be achieved and/or maintained such as patients with rickets/osteomalacia, osteoporosis, chronic kidney disease and kidney transplant recipients, malabsorption, primary hyperparathyroidism, granulomatous disease, and those receiving treatments potentially inducing bone loss. Other patients in whom vitamin D concentration may be measured are those with symptoms compatible with a severe vitamin D deficiency or excess persisting without explanation such as those with diffuse pain, or elderly individuals who fall, or those receiving treatments which modify vitamin D metabolism such as some anti-convulsants. Measurement of Vitamin D concentrations should also be part of any exploration of calcium/phosphorus metabolism which includes measurement of serum calcium, phosphate and PTH.
    Scandinavian journal of clinical and laboratory investigation. Supplementum 04/2012; 243:129-35. DOI:10.3109/00365513.2012.682888
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