The main objective of the Nutri-D study is to establish the effect of seasonal variations in vitamin D on a cohort of Slovenian adults. We will also investigate the association between vitamin D status and different Caucasian phototypes, and skin colour in the melanin index. The secondary objective is to review the effectiveness of various vitamin D supplement formulations.

Participating organizations:

• Nutrition Institute  (project leader: Prof. Dr Katja Žmitek)
• Faculty of Applied Sciences
• University Clinical Center Ljubljana
• National Institute of Public Health

Project duration: 1.7.2019 - 30.6. 2022

Financing:

• Slovenian Research Agency
• Valens Int. d.o.o.
• Ministry of Health of the Republic of Slovenia

Project goals:
In the first part of the project, we will examine the effect of the seasonal variations in vitamin D on a cohort of 250 Slovenian adults. We will also investigate the association between vitamin D status and different Caucasian phototypes, and skin colour in the melanin index (MI). The results of the study will provide important data on seasonal variations in the status of vitamin D in Slovenia, additional strength of the study will be the monitoring of the same participants in different seasons (summer and winter).

In the second part of the study, we will test the effectiveness and bioavailability of various vitamin D supplement formulations in the adult population with suboptimal vitamin D status. 

In the third in fourth part, we will identify the major dietary sources of vitamin D in prepacked foods. We will focus on dietary supplementation practices, and with the acquired data we will develop a preliminary tool for identifying individuals at risk for vitamin D deficiency.

Selected literature:

• HRIBAR, Maša, BENEDIK, Evgen, GREGORIČ, Matej, BLAZNIK, Urška, KUKEC, Andreja, HRISTOV, Hristo, ŽMITEK, Katja, PRAVST, Igor. A systematic review of vitamin D status and dietary intake in various Slovenian populations = Sistematični pregled prehranskega vnosa in preskrbljenosti z vitaminom D v Sloveniji. Zdravstveno varstvo : Slovenian journal of public health. [Tiskana izd.]. 2022, letn. 61, št. 1, str. 55-72. ISSN 0351-0026. https://sciendo.com/issue/SJPH/61/1, DOI: 10.2478/sjph-2022-0009
• ŽMITEK, Katja, HRIBAR, Maša, HRISTOV, Hristo, PRAVST, Igor. Efficiency of vitamin D supplementation in healthy adults is associated with body mass index and baseline serum 25-hydroxyvitamin D level. Nutrients. 2020, vol. 12, iss. 5, str. 1-15, ilustr. ISSN 2072-6643. https://www.mdpi.com/2072-6643/12/5/1268