SHORT COMMUNICATION Vitamin D fortification as public health policy: significant improvement in vitamin D status in young Finnish men IT Laaksi 1 , J-PS Ruohola 2 , TJ Ylikomi 1,3 , A Auvinen 4 , RI Haataja 5 , HK Pihlajama ¨ki 6,7 , PJ Tuohimaa 3,8 1 Department of Cell Biology, Medical School, University of Tampere, Tampere, Finland; 2 Garrison Hospital, Pori Brigade, Finnish Defence Forces, Sa¨kyla¨, Finland; 3 Department of clinical chemistry, Tampere University Hospital, Tampere, Finland; 4 Department of Epidemiology, Tampere School of Public Health, University of Tampere, Tampere, Finland; 5 Department of Biometrics, Tampere School of Public Health, University of Tampere, Tampere, Finland; 6 Department of Medical Services, Defence Staff, Finnish Defence Forces, Helsinki, Finland; 7 Institute of Military Medicine, Central Military Hospital, Helsinki, Finland and 8 Department of anatomy, Medical School, University of Tampere, Tampere, Finland Background: Vitamin D insufficiency is common in northern countries during wintertime. In Finland, after the recommendation by the Ministry of Social Affairs and Health, vitamin D has been added to liquid milk products and margarines from February 2003. Objective: We determined the effects of national policy on vitamin D fortification on vitamin D status among young Finnish men. Design: A comparison before and after intervention with study population of 196 young Finnish men (18–28 years) was carried out. Serum 25-hydroxyvitamin D 3 (25-OHD 3 ) concentrations were determined with the OCTEIA s enzymeimmunoassay by IDS (Immunodiagnostic Systems Limited, Bolden, UK) in January 2003 (n ¼ 96) and in January 2004 (n ¼ 100), nearly 1 year after national vitamin D fortification had started. Results: The mean serum 25-OHD 3 concentrations during the wintertime increased by 50% after implementation of the vitamin D fortification of dairy products. Correspondingly, the prevalence of vitamin D insufficiency (serum 25-OHD 3 o40 nmol/l) was decreased by 50% from 78% in January 2003 to 35% in January 2004. Conclusions: Our results demonstrate that national vitamin D fortification substantially improved the vitamin D status of young Finnish men. Still, a third remained vitamin D insufficient. European Journal of Clinical Nutrition (2006) 60, 1035–1038. doi:10.1038/sj.ejcn.1602414; published online 15 February 2006 Keywords: vitamin D; insufficiency; milk; fortification; wintertime; 25-hydroxyvitamin D 3 ; 25-OHD 3 Introduction Vitamin D regulates calcium and phosphate homeostasis by increasing their absorption from intestine and enhancing their renal reabsorption (Holick, 2003a, b). This homeostasis is important for bone mineralization since in the case of inadequate calcium in the diet vitamin D causes osteoclasts to mature and dissolve calcium from bone. A low serum concentration of vitamin D leads to a lower serum calcium concentration and thereafter to an increased PTH secretion, that is, secondary hyperparathyroidism which follows that bone turnover increases (Lips, 2001). Rickets in childhood, mild osteomalacia, osteoporosis and an increased risk of hip and other fractures in adults are all known consequences of vitamin D deficiency (Compston, 1998; Utiger, 1998). Vitamin D is also a hormone. Its genomic mechanism of action is mediated by vitamin D receptor, which belongs to the family of steroid/thyroid hormone nuclear receptors. It has antiproliferative, differentiative and apoptotic effects Received 1 May 2005; revised 31 October 2005; accepted 5 January 2006; published online 15 February 2006 Correspondence: Dr IT Laaksi, Department of Cell Biology, Medical School, University of Tampere, Medisinarinkatu 3, Tampere 33014, Finland. E-mail: ilkka.laaksi@uta.fi Guarantor: IT Laaksi. Contributors: ITL and J-PSR were involved in designing the study and collected and analysed the data. AA was involved in data analysis and statistical analysis. RIH was involved in statistical analysis. TJY, HKP and PJT were involved in study design and data analysis. ITL wrote the first draft of the paper and all authors contributed to the final draft. European Journal of Clinical Nutrition (2006) 60, 1035–1038 & 2006 Nature Publishing Group All rights reserved 0954-3007/06 $30.00 www.nature.com/ejcn