Safety of Vitamin D Food Fortification and Supplementation: Evidence from Randomized Controlled Trials and Observational Studies

Contribution of different vitamin D forms and fortified foods to vitamin D intake in Europe: a narrative review

In the current narrative review, the bioavailability of the main vitamin D forms is evaluated. The mean intakes and main contributing forms of vitamin D in the European diet are estimated, as well as the major contributing dietary sources. The literature is reviewed for studies reporting on the proportion of users and non-users of fortified food with vitamin D intakes below reference intakes. In addition, the availability of vitamin D-fortified prepackaged retail products and fortification levels in the European market is assessed. Previously, vitamins D2 and D3 forms were considered the primary forms in the diet. Recent analytical methods suggest that dietary 25(OH)D3, when adjusted for higher bioequivalence, significantly contributes to total vitamin D intakes. When also considering 25(OH)D3 from foods, the estimated vitamin D intake from an average European diet was 3.8µg/d of total Vitamin D Equivalents: vitamin D3, vitamin D2 and 25(OH)D3, contributing about 71%, 2%, and 27%, respectively. Animal foods, fortified fats and spreads contributed most to total intakes. Literature suggests that 94-100% of Europeans aged ≥13y fail to meet the vitamin D reference intake of 10µg/d. About 98-100% of vitamin D-fortified food users and 99-100% of non-users in the UK and Netherlands consumed less than 10µg/d of vitamin D. About 1.2% of prepackaged foods and drinks were voluntary fortified with vitamin D, margarine and plant-based drinks providing most of the daily vitamin D. Encouraging fortification and other strategies may support closing the gap between current and recommended vitamin D intakes.

Strategies for preventing bone loss in populations with insufficient calcium and vitamin D intake

Calcium and vitamin D are essential nutrients for maintaining skeletal health, yet deficiencies in these nutrients are particularly widespread in regions such as Asia and Africa. Inadequate intake of these nutrients in these areas has been associated with diminished bone integrity and a rising incidence of osteoporosis. This review examines the underlying mechanisms of bone loss driven by calcium and vitamin D deficiencies, emphasizing their crucial roles in bone metabolism. It also presents strategies to improve nutrient intake, such as fortification of staple foods and supplementation, along with lifestyle modifications including increased physical activity, sun exposure, and dietary education, to prevent bone loss effectively. Special consideration is given to vulnerable populations, including older adults, individuals with limited sun exposure, and those with dietary restrictions, who are at higher risk of deficiency. The review further evaluates public health strategies, including government-initiated fortification and educational programs, as essential measures for tackling widespread nutrient deficiencies. Lastly, it explores future avenues for addressing calcium and vitamin D deficiencies, including the potential role of digital health tools, personalized nutrition, and innovative public health policies to alleviate the global burden of bone-related diseases.

The Impact and Efficacy of Vitamin D Fortification

Vitamin D deficiency is a global health issue linked to various chronic diseases and overall mortality. It primarily arises from insufficient sunlight exposure, compounded by dietary limitations. Vitamin D fortification of commonly consumed foods has emerged as a viable public health intervention to address this deficiency. This review evaluates the impact of vitamin D food fortification on serum levels, intake, and health outcomes and explores the stability, bio-accessibility, bioavailability, and cost-effectiveness of such interventions. A comprehensive literature search was conducted in PubMed and Google Scholar, focusing on studies from 2015 to 2024. The criteria included primary research on healthy adults that addressed the effects of vitamin D fortification on health, intake, and serum levels, as well as the fortification's stability, bio-accessibility, bioavailability, and cost-effectiveness. Studies were extracted and analyzed according to PRISMA guidelines. The review included 31 studies from diverse geographic locations, revealing that fortifying dairy products, cereals, fats, oils, and other food items effectively increased serum 25-hydroxyvitamin D levels. The fortification methods varied, with vitamin D3 showing superior efficacy over vitamin D2. Encapsulation techniques improved stability and bioavailability. Fortifying staple foods like milk and eggs proved cost-effective compared with pharmaceutical interventions. Vitamin D food fortification significantly enhances serum levels and intake, with dairy and cereals being the most frequently fortified. Standardized fortification guidelines are essential to ensure safety and efficacy. Ongoing evaluation and region-specific policies are crucial for effectively optimizing fortification strategies and addressing vitamin D deficiency.

Optimisation of vitamin D status in global populations

Vitamin D is important for musculoskeletal health. Concentrations of 25-hydroxyvitamin D, the most commonly measured metabolite, vary markedly around the world and are influenced by many factors including sun exposure, skin pigmentation, covering, season and supplement use. Whilst overt vitamin D deficiency with biochemical consequences presents an increased risk of severe sequelae such as rickets, osteomalacia or cardiomyopathy and usually warrants prompt replacement treatment, the role of vitamin D supplementation in the population presents a different set of considerations. Here the issue is to keep, on average, the population at a level whereby the risk of adverse health outcomes in the population is minimised. This position paper, which complements recently published work from the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases, addresses key considerations regarding vitamin D assessment and intervention from the population perspective. This position paper, on behalf of the International Osteoporosis Foundation Vitamin D Working Group, summarises the burden and possible amelioration of vitamin D deficiency in global populations. It addresses key issues including screening, supplementation and food fortification.

Vitamin D fortification of foods - sensory, acceptability, cost, and public acceptance considerations

In terms of vitamin D food fortification, there are a number of important considerations in relation to selection of the food vehicle and fortificant. While there has been much research focus on the ability of fortified foods to improve vitamin D status, other considerations, such as sensory properties and acceptability, cost, and public attitudes around vitamin D-fortified foods, have received less attention. Thus, the present narrative review aimed to summarize the existing knowledge around these important considerations. In summary, its findings suggest that: i) vitamin D addition to various food vehicles, at levels consistent with the supply of part or all the recommended intake, does not alter their sensory characteristics or overall acceptability; ii) overall, vitamin D fortification of foods is relatively cost-effective, despite the fact that some attitudinal studies highlighted participant concerns about the potential cost/expense of vitamin D-fortified foods; iii) evidence from various attitudinal studies suggest a high level of acceptance and/or purchase intention (i.e., extent to which customers are willing and inclined to buy) of vitamin D-fortified food products by the general public; and iv) there have been repeated calls for vitamin D public health educational/information campaigns to help educate consumers about the health risks associated with vitamin D deficiency and nutritional benefits associated with consumption of vitamin D-fortified foods. Such campaigns could positively mediate attitudes and acceptance of vitamin D-fortified foods amongst the public, and could also help address misconceptions and allay fears around vitamin D for concerned individuals. Lastly, the findings of the present review also highlight the existence of between-country differences, even within Europe, in relation to attitudes and purchase intention of vitamin D-fortified foods and the perceived appropriateness of certain food vehicles for vitamin D fortification, as well as the best mix of communication channels for a vitamin D public health educational/information campaign.

Vitamin D Supplementation: A Review of the Evidence Arguing for a Daily Dose of 2000 International Units (50 µg) of Vitamin D for Adults in the General Population

Vitamin D deficiency is considered a public health problem due to its worldwide high prevalence and adverse clinical consequences regarding musculoskeletal health. In addition, vitamin D may also be crucial for the prevention of certain extraskeletal diseases. Despite decades of intensive scientific research, several knowledge gaps remain regarding the precise definition of vitamin D deficiency and sufficiency, the health benefits of improving vitamin D status, and the required vitamin D intakes. Consequently, various societies and expert groups have released heterogeneous recommendations on the dosages for vitamin D supplementation. In this brief narrative review, we outline and discuss recent advances regarding the scientific evidence arguing for a daily vitamin D supplementation with 2000 international units (IU) (50 µg) of vitamin D3 to prevent and treat vitamin D deficiency. According to data from randomized controlled trials (RCTs), such a dose may improve some health outcomes and is sufficient to raise and maintain serum 25(OH)D concentrations above 50 nmol/L (20 ng/mL) and above 75 nmol/L (30 ng/mL) in >99% and >90% of the general adult population, respectively. According to large vitamin D RCTs, there are no significant safety concerns in supplementing such a dose for several years, even in individuals with an already sufficient vitamin D status at baseline. A daily vitamin D supplementation with 2000 IU (50 µg) may be considered a simple, effective, and safe dosage to prevent and treat vitamin D deficiency in the adult general population.

Knowledge, attitudes, and practices associated with vitamin D supplementation: A cross-sectional online community survey of adults in the UK

OBJECTIVE

Assess knowledge, attitudes, and practices (KAPs) of a diverse population. Identify barriers and facilitators that inform routine vitamin D supplementation and self-care in the community setting.

DESIGN

Cross-sectional online voluntary survey. Electronic survey link published on college Qualtrics platform and advertised widely. Study information provided with Participant Information Sheet.

SETTING AND PARTICIPANTS

556 community dwelling adults across the UK.

METHODS

The overarching study included two phases, incorporating quantitative and qualitative methodologies. This paper reports findings from the first phase of the FABCOM-D (Facilitators and Barriers to Community (Healthy) Vitamin D status) study. Online survey questions were iteratively developed after background literature searches and piloted to ensure clarity and ease of understanding. Survey responses summarised using frequencies and percentages, and univariable and multivariable logistic regression models explored for any association. A p-value less than 0.05 was considered statistically significant. The Checklist for Reporting Results of Internet E-Surveys guided reporting. Statistical analysis performed using IBM SPSS software.

MAIN OUTCOME MEASURES

Awareness of vitamin D information sources, health benefits and testing. Attitudes to supplementation, sun exposure and fortification.

RESULTS

Three quarters of the community had some awareness of vitamin D and around half were taking supplements. The two most trusted sources of information included health professionals and the NHS website. Participants were willing to pay for supplements, supporting a self-care agenda. With increasing age, there was significant reduced intake of vitamin D supplements. This aspect needs to be explored further as this could be a concern in deficiency status in the elderly. There was acceptance of food fortification but uncertainty on how to balance food intake with supplementation.

CONCLUSION

We were successful in eliciting views on KAPs around vitamin D from a community population including a large proportion of Black and Minority Ethnic individuals. The community wanted information and guidance to help manage individual vitamin D status, especially for high-risk groups, and on balancing supplementation, food fortification and sun exposure.

Nutritional risks in children with food allergy

BACKGROUND

Food allergies (FA) are a growing problem in the pediatric population and clinical features differ according to the underlying immunological mechanisms. While the primary management strategy is to eliminate the culprit food from the diet, assessment of the potential nutritional risks of elimination is also an integral part of management. In cases that do not improve over time; if you have basic food allergies and multiple food allergies, this can also lead to negative nutritional consequences. The contribution of basic nutrients, economical and easily accessible foods to the diet, is critical and has an important place in meeting the daily adequate intake of many nutrients. In the presence of food allergy, it is necessary to meet the vitamins and minerals that cannot be obtained from allergic foods, with alternative sources or supplements. For example, insufficient calcium intake in cow's milk allergy (CMA), the most common FA in early childhood, is very likely if an alternative supplement has not been introduced. In the management of CMA, choosing the appropriate formula and/or supplement for the clinical characteristics of children, when necessary, has an important place. In conclusion, nutritional risk assessment of children with FA requires a comprehensive, detailed, and multidisciplinary approach.

Vegan nutrition: a preliminary guide for health professionals

Since the beginning of the 21st century, interest in vegan diets has been rapidly increasing in most countries. Misconceptions about vegan diets are widespread among the general population and health professionals. Vegan diets can be health-promoting and may offer certain important advantages compared to typical Western (and other mainstream) eating patterns. However, adequate dietary sources/supplements of nutrients of focus specific to vegan diets should be identified and communicated. Without supplements/fortified foods, severe vitamin B12 deficiency may occur. Other potential nutrients of focus are calcium, vitamin D, iodine, omega-3 fatty acids, iron, zinc, selenium, vitamin A, and protein. Ensuring adequate nutrient status is particularly important during pregnancy, lactation, infancy, and childhood. Health professionals are often expected to be able to provide advice on the topic of vegan nutrition, but a precise and practical vegan nutrition guide for health professionals is lacking. Consequently, it is important and urgent to provide such a set of dietary recommendations. It is the aim of this article to provide vegan nutrition guidelines, based on current evidence, which can easily be communicated to vegan patients/clients, with the goal of ensuring adequate nutrient status in vegans.

Vitamin D Is Associated with Clinical Outcomes in Patients with Primary Biliary Cholangitis

Vitamin D (VD) deficiency has been associated with clinical outcomes in patients with chronic liver disease. This study aims to identify the prevalence of VD deficiency in patients with primary biliary cholangitis (PBC) and its association with treatment response to ursodeoxycholic acid (UDCA), cirrhosis development, and liver-related events (mortality and liver transplantation). Two hundred and fifty-five patients with PBC diagnosis were evaluated. Patients with VD levels below 50 nmol/L were defined as deficient. Treatment response to UDCA was defined according to the Toronto criteria. Independent risk factors were identified using binary logistic and Cox regression analysis. The mean level of serum VD was 77 ± 39 nmol/L, and 64 patients (25%) were VD deficient. Incomplete response to UDCA was more prevalent in VD-deficient patients compared to their counterparts (45% vs. 22%; p < 0.001). The risk of cirrhosis development (hazard ratio (HR) 1.93; 95% confidence interval (CI) 1.17–3.19, p = 0.01) and liver-related mortality or need for liver transplantation (HR 3.33, 95% CI, 1.57–7.07, p = 0.002) was higher in VD-deficient patients after adjusting for confounders. Vitamin D deficiency is frequent in patients with PBC and is associated with incomplete response to UDCA, cirrhosis development, and liver-related mortality or need for liver transplantation.