Abstract
Vitamin D is a unique nutrient that has captured the attention of scientific and medical communities, regulatory authorities and the general public over recent years. Low vitamin D status is a worldwide public health concern and occurs across all age, sex and ethnic groups. Dietary requirements for vitamin D have been re-evaluated and revised over recent years by several authoritative bodies, including the Institute of Medicine, the Nordic Council of Ministers, the European Food Safety Authority and, of course, the UK Scientific Advisory Committee on Nutrition. However, a lack of vitamin D dose-response trials in children and adolescents prior to these reports has hindered the development of evidence-based dietary requirements for vitamin D in these population subgroups. Two recent randomised controlled trials have addressed this significant knowledge gap and estimated that intakes of between 6 and similar to 30 mu g/day are needed during the winter time to avoid vitamin D deficiency and ensure adequacy in healthy White 4-8 year-old children residing in Denmark (55 degrees N) and 14-18 year-old adolescents residing in the UK (51 degrees N). These new data suggest that, while the current vitamin D recommendations of 10-15 mu g/day for children and adolescents will help avoid winter-time vitamin D deficiency (25-hydroxyvitamin D concentrations < 25-30 nmol/l), they remain inadequate for ensuring vitamin D concentrations are maintained above 40-50 nmol/l, which may be necessary for optimal bone accretion during these rapid growth phases. Such data will allow for the ongoing refinement of evidence-based dietary requirements for children and adolescents.