Despite the explosion of scientific research in vitamin D and health, particularly in basic research at the mechanistic level, there are many fundamental gaps in the field of vitamin D from the public health perspective. Incredibly, these include the magnitude of the deficiency problem among European residents. Vitamin D requirements during pregnancy and throughout childhood and adolescence are unknown. The perennial question of whether associations between vitamin D status and non-skeletal health are independent of co-related factors such as pre-existing risk, obesity and compromised nutritional status, remains controversial. The ODIN consortium has adopted a triage approach to selecting the most critical issues for attention. From a population health perspective, given the lack of basic data in the vitamin D field, a step-wise approach starting with quantification of the prevalence of low vitamin D status followed by identification of food-based strategies to increase vitamin D intakes across the population distribution, and prevent vitamin D deficiency, must be the number one priority at this time. ODIN aims to fill these basic knowledge gaps and will approach the problem from the perspective that vitamin D, like all nutrients, is required in small quantities on a continuous basis. High-dose, short-term pharmaceutical approaches to treating nutritional deficiencies historically have a poor record from a population health perspective; the ODIN consortium considers this an inappropriate strategy for vitamin D, which is a fat-soluble vitamin with incompletely understood storage and mobilization mechanisms. Implementation of strategies for deficiency prevention that are developed with the guiding principle of minimizing the dual hazards of nutrient inadequacy and excess is warranted.