Vitamin D and food fortification

There is widespread acknowledgment that low vitamin D status is prevalent in the community, and public health measures are required to prevent deficiency. Currently, the major regulatory authorities recommend vitamin D intakes in the order of 10-20μg/day, depending on age and whether the serum 25-hydroxyvitamin D [25(OH)D] target is ≥25 or ≥50nmol/L. Naturally rich sources of vitamin D are few and infrequently consumed, and nutrition surveillance data from various countries have indicated that habitual vitamin D intakes in the population are much lower than the recommendations. There is a need for sustainable food-based strategies to bridge the gap between current and recommended intakes of vitamin D to minimize the prevalence of low serum 25(OH)D concentrations, without increasing the risk of excessive intakes. Evidence is now overwhelming, from multiple strands including RCTs, systematic reviews, and metaanalyses of RCTs among adults and children across the globe, that vitamin D fortification is effective in preventing low vitamin D status during UVB deprivation. National surveys and case studies of countries that have implemented fortification strategies with appropriate monitoring have demonstrated that targeted approaches can bridge the gap between current and recommended intakes of vitamin D, without increasing the risk of excessive intakes. However, very few countries have developed evidence-based policies for vitamin D fortification, and only one country has performed a nationwide evaluation of its policy. This chapter reviews vitamin D in the food supply, and the current evidence basis for development of food fortification strategies, using both nutrient addition to manufactured staples and vitamin D enhancement in primary production.