Projects / Programmes source: ARRS

Challenges in achieving adequate vitamin D status in the adult population

Research activity

Code Science Field Subfield
3.08.00  Medical sciences  Public health (occupational safety)   
1.09.00  Natural sciences and mathematics  Pharmacy   

Code Science Field
B420  Biomedical sciences  Nutrition 

Code Science Field
3.03  Medical and Health Sciences  Health sciences 
3.01  Medical and Health Sciences  Basic medicine 
vitamin D, vitamin D2, vitamin D3, ergocalciferol, cholecalciferol, vitamin D deficiency, bone health, skin phototype, skin colour
Evaluation (rules)
source: COBISS
Researchers (17)
no. Code Name and surname Research area Role Period No. of publications
1.  27975  PhD Urška Blaznik  Public health (occupational safety)  Researcher  2019 - 2022  176 
2.  05373  PhD Ivan Eržen  Public health (occupational safety)  Researcher  2019 - 2022  651 
3.  35405  Teja Fabjan  Medical sciences  Researcher  2019 - 2022  40 
4.  24228  PhD Matej Gregorič  Public health (occupational safety)  Researcher  2019 - 2022  211 
5.  39476  Maša Hribar  Public health (occupational safety)  Researcher  2019 - 2022  47 
6.  51995  PhD Hristo Hristov  Public health (occupational safety)  Researcher  2019 - 2022  47 
7.  39073  Petra Keršmanc  Natural sciences and mathematics  Technician  2019 - 2022  38 
8.  54315  Sanja Krušič  Public health (occupational safety)  Researcher  2020 - 2022 
9.  34577  Kristina Kumer  Human reproduction  Researcher  2019 - 2022  55 
10.  22463  PhD Anita Kušar  Plant production  Researcher  2019 - 2022  102 
11.  39242  PhD Nina Mikec  Biochemistry and molecular biology  Junior researcher  2019 - 2020  19 
12.  10691  PhD Joško Osredkar  Human reproduction  Researcher  2019 - 2022  1,274 
13.  51498  Tina Pogačnik  Natural sciences and mathematics  Researcher  2019 - 2022  30 
14.  24300  PhD Igor Pravst  Public health (occupational safety)  Researcher  2019 - 2022  283 
15.  35750  Vera Troha Poljančič    Technician  2019 - 2022 
16.  09178  PhD Janko Žmitek  Pharmacy  Researcher  2019 - 2022  296 
17.  24278  PhD Katja Žmitek  Public health (occupational safety)  Principal Researcher  2019 - 2022  158 
Organisations (4)
no. Code Research organisation City Registration number No. of publications
1.  0312  University Medical Centre Ljubljana  Ljubljana  5057272000  73,445 
2.  2885  VIST - Faculty of Applied Sciences  Ljubljana  2288591  792 
3.  3018  NUTRITION INSTITUTE  Ljubljana  3609081000  456 
4.  3333  National Institut of Public Health  Ljubljana  6462642  17,170 
Vitamin D (VitD) is a pro-hormone essential for normal growth, skeletal development and optimal bone mineral density. There is also evidence that VitD reduces risk of many diseases not related to bone health. Therefore, reaching and maintaining an optimal VitD status at all life stages is of major individual and public health importance. VitD in the body may come both from dietary sources and from biosynthesis in the skin triggered by UVB irradiation. Sunlight exposure, rather than diet, has been reported as the main resource for the majority of the population. Slovenia is Central European country and its latitude ranks it amongst the countries where seasonal variation in VitD is expected due to lower intensity of UVB radiation during winter. However, there are no available data regarding VitD status in the general adult population and there is no systematic screening for individuals at risk. In Slovenia no VitD fortification or supplementation policies have been implemented, except for children up to 1 year. To date there were only two cross-sectional studies investigating VitD status in Slovenia, both conducted on pregnant women and results showed high prevalence of VitD hypovitaminosis - VitD deficiency and insufficiency were observed in aprox. half of the women. Additionally, mean daily intake of VitD was significantly lower than the recommended dietary allowance. Those results are also indicator that VitD status migh not be optimal in the general adult population in Slovenia, especially in winter season, and should be further elucidated. Besides environmental factors and lifestyle habits, skin color is an important determinant of VitD status. Results of the studies comparing individuals from different ethnic backgrounds show that darker skin requires higher amount of UVB radiation for efficient VitD biosynthesis in skin. On the contrary results of the only study focusing on the phototypes within Caucasian cohort showed that fair skin types have lower levels VitD compared to darker Caucasian skin types and are most at risk of VitD deficiency. Slovenian population, being predominantly Caucasian, will provide an opportunity to further elucidate connection between skin colour and VitD status within Caucasian cohort. The proposed project's overall hypothesis is that in Slovenian population there are considerable seasonal variations of vitamin D status in adults with the particularly high prevalence of suboptimal vitamin D status during winter time, and that adequate supplementation should be recommended at least for specific populations. Applying a highly multidisciplinary approach, we will:   O1: identify major dietary sources of Vitamin D in the Slovenian population, particularly focusing into the assessment of food enrichment practices in the absence of regulatory requirements; O2: determine seasonal variations in vitamin D status on a cohort of Slovenian adults using longitudinal study design; O3: investigate association between vitamin D status and different Caucasian phototypes, skin colour and melanin index; O4: determine the efficiency of different vitamin D formulations in treating suboptimal vitamin D status in adult population, providing insights into the influence of formulation on vitamin D absorption (randomised controlled intervention with three different Vitamin D formulations; two months of treatment using 1000 IU of vitamin D); O5: develop questionnaire-based screening tool, that could be used for identification of individuals at risk for suboptimal Vitamin D status, which will enable identification of subjects to be included into further diagnostics within the healthcare system; O6: investigate consumer’s awareness and health literacy related with vitamin D, and supplementation practices during winter season; O7: support policymakers with evidence needed for future decisions to support optimal status of vitamin D in the population. The data will be important for improving nutritional r
Significance for science
The proposed project will provide epidemiological data regarding VitD (VitD) status and its seasonal variations for Slovenian adult population. As in Slovenia currently we actually have NO data on VitD status in population, such data would be indispensable for the creation of appropriate policies and further research, particularly for identification of new links between nutrition and health. A major strength of WP2 study is following a cohort of individuals over a year rather than assessing different individuals in different seasons. Such longitudinal study approach, rarely used for assessments of VitD seasonal variations, will enable more effective assessment of the relative contribution of within- and between-subject factors that may influence VitD status. We will also further exploit and provide new important data on the connection between different skin phototypes, and for the first time also skin colour as well as melanin index with VitD status and its seasonal variations within Caucasian cohort. This connection is not yet well studied, as most studies focused on comparisons of individuals of different ethnic backgrounds, but there are indications that this connection within Caucasian population deviates from results of those studies.   Project will provide also new insights into the influence of product formulation on efficiency of VitD preparations and enable further research and development of new products. It has been established that food matrix has apparently some effect on VitD absorption, while the effects of constituents in formulations are poorly investigated. As variety of very different formulations of VitD food supplements are available (powdered formulations, oil and water-based products), it will give valuable results on their efficiency to improve sub-optimal VitD status. Results will support future supplementation practices and public advices. Project will also contribute to the methodology in the area of the assessment of VitD status; one of the projects objective is development of VitD deficiency screening tool, which could be implemented into national health care system.   For the first time, major dietary sources of VitD in processed foods will be identified, and that would be done using innovative sales-weighing approach. Until now such approach has been used only for a few nutrients, never for VitD. Nowadays food retailers operate with data that would enable unprecedented insights into consumers’ exposure to all kinds of food constituents and support risk assessments, but currently these data are mostly underexplored. Our research has a unique opportunity and infrastructure to use such data for public health research (contracts with major retailers in Slovenia, which provide us with yearly sales data on the product level).   Considering the described impact, we believe that results of this project will be original and will contribute to the scientific development in global prospective in the areas of nutrition and public health, food technology and pharmacy.
Significance for the country
The project results will significantly improve progress in research in the areas of nutrition and public health, food technology and pharmacy. Project’s relevance for society is proven by the co-funding by the Government (Ministry of Health; 15.000 EUR and its results be used as a scientifically credible basis for the adoption of appropriate health care and public health policies, guidelines, and preventive programs. Project objectives are consistent with the National Programme on Nutrition and Physical Activity for Health 2015-25. This programme states the importance of research in the field of nutrition, especially: a) the priorities of Horizon 2020 program (Health and food safety), b) strengthening interinstitutional cooperation, c) the need for collection of data on dietary habits and regular monitoring of the status and trends in the field of dietary intake of population, d) education and training. The proposed project will contribute to better realisation of all these areas. The project’s objectives are also in line with Slovenian strategic resolution on the development of Slovenian agriculture and the food industry until 2020 “Food for the future”. Project results will also contribute to the development of science in the field of nutrition and medicine, food technology and pharmacy as it will contribute important results about seasonal variations of vitamin D (VitD) in Slovenia; very relevant data on VitD status will be provided. The collected data will be indispensable not only for the creation of appropriate policies, but also for further research, particularly in interconnected areas of nutrition, health and non-communicable diseases. Data from the proposed applied project will present an upgrade to the EU MENU/NUTRIHEALTH project (finishing in 2020, funders EFSA/SRA). The project will also improve international cooperation and reputation of Slovenian science in the world. Project will be also very important for the businesses, specifically for the segment related with VitD preparations (food industry: enriched foods and dietary supplements; pharmaceutical industry: VitD preparations). The industry will be provided with very important data on the epidemiology of insufficient VitD status in the population, with potential impact on the supply and marketing of the preparations containing VitD. Additionally, project results will support production of more efficient VitD formulations and particularly, enable evidence-based directions of their use. With relevant data, the industry will have the data needed for more responsible product development, and possible potential for VitD food enrichment. The importance of the project for the industry is proven by the co-funding by Valens Int d.o.o. (a min. of 85.000 EUR), a fast-growing Slovenian SME, specialised into production of active ingredients for the food industry and dietary supplements. The company export in 2018 will be over 65%, with average 25% yearly income growth in last 3 years.
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