Vitamin D: do we get enough? A discussion between vitamin D experts in order to make a step towards the harmonisation of dietary reference intakes for vitamin D across Europe.

Unlabelled: On September 29, 2011, acknowledged experts in the field of vitamin D, mainly European, were brought together in order to discuss the recent scientific advances in relation to vitamin D: the current requirements and associations with various health outcomes. In this article, the discussions resulting from the meeting are summarized.

Introduction: Several groups at risk for developing vitamin D insufficiency have been identified. Accordingly, reviews indicate that a significant percentage of the population worldwide have serum 25-hydroxyvitamin D levels below 50 nmol/l. In addition to the role of vitamin D in bone health, recent studies suggest that it may play a pivotal role in other systems, e.g., the cardiovascular system, pancreas, muscle, immune system and brain. Most evidence, however, is obtained from observational studies and yet inconclusive.

Methods: To exchange and broaden knowledge on the requirements for vitamin D and its effect on various health outcomes, a workshop entitled "Vitamin D Expert Meeting: Do we get enough?", was organized.

Results: Despite low vitamin D levels worldwide, consensus on the definition of deficiency is not yet reached. In order to define cut-off points for vitamin D whilst taking into account extraskeletal health effects, randomized controlled trials in these fields are warranted. The experts do emphasize that there is evidence to suggest an important role for vitamin D in the maintenance of optimal bone health at all ages and that vitamin D supplementation, in most studies co-administered with calcium, reduces fracture risk in the senior population.

Conclusion: To reach a serum 25-hydroxyvitamin D level of 50 nmol/l older adults aged ≥65 years are therefore recommended to meet a mean daily vitamin D intake of 20 μg (800 IU), which is best achieved with a supplement.