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Vitamin D status and effects of food fortification in families

Madsen, Katja Howarth; Rasmussen, Lone Banke; Andersen, Rikke; Andersen, Elisabeth Wreford; Mølgaard, Christian

Publication date: 2014 Document Version Publisher's PDF, also known as Version of record Link to publication

Citation (APA): Madsen, K. H., Rasmussen, L. B., Andersen, R., Andersen, E. W., & Mølgaard, C. (2014). Vitamin D status and effects of food fortification in families. National Food Institute, Technical University of Denmark.

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Vitamin D status and effects of food fortification in families

Katja Howarth Madsen PhD Thesis 2013

Preface This PhD study was conducted at the Division of Nutrition, National Food Institute, Technical University of Denmark between November 2009 and November 2013 including maternity leave. The PhD thesis is based on three papers written on data from the VitmaD study. The work was supported by grants from the Danish Dairy Research Fund, Centre for Advanced Food Studies and The European Regional Development Fund. Arla Foods A/S, Lantmännen Cerealia A/S and The Association of Danish Trade Mills partially sponsored the study foods. First of all I would like to thank my supervisors Lone Banke Rasmussen, Rikke Andersen, Elisabeth Wreford Andersen and Christian Mølgaard for always taking their time, invaluable support and discussions. I gratefully acknowledge the work done by the VitmaD project team (Heddie Mejborn, Lone Banke Rasmussen, Rikke Andersen, Janna Nissen, Anna Klöcker and Ida Ipsen), for whom it would not have been possible to run the study. I also appreciate the colleagues at the Division of Nutrition with special thanks to Professor Inge Tetens for great inspiration. I thank my office partner Janna Nissen for the many talks in ups and downs. I am grateful to all the families for their active and enthusiastic participation in the VitmaD study. I thank the students from Metropolitan University College for assistance with examination of the families and master student Johanne Kierkegaard Severinsen from University of Copenhagen for her work with the evaluation of the FFQ. I also value the great co-operations with our colleague Jette Jakobsen from Division of Food Chemistry, Arla Foods A/S, Lantmännen Cerealia A/S and their cooperative baker, the association of Danish Consumer Co-operatives and their supermarkets Dagli Brugsen in Mørkhøj, former Super Brugsen in Bagsværd and Kvickly in Buddinge, Copenhagen´s General Practitioners Laboratory in Søborg and the Biochemical Department at Holbæk Hospital.

English summary Background and aims: The importance of vitamin D in bone health is recognised and low concentrations have been associated with increased risk of disease. Cutaneous synthesis is considered the major source of vitamin D, but during winter where sufficient sun exposure is restricted at Northern latitudes, intake from food and dietary supplements become essential. Vitamin D intakes are lower than dietary recommendations in most populations and low vitamin D status is common. The PhD thesis is based on the VitmaD study in which a realistic and model derived fortification strategy was investigated in a real-life setting. The aim was to investigate the effect of increasing vitamin D intake by fortification of milk and bread to the amount recommended in the Nordic Nutrition recommendations (NNR) on serum 25(OH)D concentration in families during winter in Denmark (paper 1). Secondly, the aim was to assess vitamin D status and its determinants at baseline of the study (paper 2). Further, to model the relationship between total vitamin D intake and serum 25(OH)D taking into account potential effect modifiers and estimate required vitamin D intake during winter (paper 3). Methods: The VitmaD study was a randomized controlled trial in 782 children and adults (4-60 years) recruited as 201 families. Families were randomly assigned to vitamin D fortified or nonfortified milk and bread for 6 months starting from September. The milk and bread replaced the subjects´ usual consumptions of products. Information on dietary intake, supplement use, health and lifestyle was obtained by self-administered web-based questionnaires. Serum 25(OH)D was analysed by liquid chromatography-tandem mass spectrometry (LC/MS-MS). Mixed models with family as a random factor were applied in all the statistical analyses. Results: At baseline of the study (late summer) the geometric mean (IQR) serum 25(OH)D concentration was 72.1 (61.5-86.7) nmol/L with no overall differences between age (P=0.190), gender (P=0.332) or age and gender groups (P=0.223) (paper 2). The prevalence of serum 25(OH)D