Effect of vitaminD3 or 25(OH)D3 Fortified Dairy on Vitmain D Status and CVD Risk Markers

There is mounting evidence to show that vitamin D deficiency may increase the risk of many common and serious diseases, including osteoporosis, cardiovascular disease, some cancers and type 1 diabetes (Holick and Chen, 2008). Hypovitaminosis D is now prevalent in the UK general population. Due to diet and lifestyle changes and the use of sun block products most people do not endogenously synthesise sufficient vitamin D from sunlight exposure (Hyppönen and Power, 2007). Therefore, vitamin D intakes from dietary sources have become very important, however this is limited as there are only a few foods naturally rich in vitamin D. Some countries (e.g. USA, Canada) fortify milk with vitamin D which results in milk being the major contributor to vitamin D intake. Vitamin D3 is the most common form used for the fortification of currently fortified foods. However, there is now some evidence that 25(OH)D3 can increase vitamin D status of humans more effectively than vitamin D3 (Bischoff-Ferrari et al, 2012; Cashman et al, 2012). To our knowledge, very few human intervention studies have compared the efficacy of 25(OH)D3 versus vitamin D3 to increase vitamin D status, and there has been no acute human study to examine the effect of the both forms of vitamin D fortified dairy products on vitamin D status in humans.