Official recommendations for vitamin D through the life stages in developed countries.

Inadequate vitamin D nutritional status is prevalent worldwide and has been associated with autoimmune disorders, heart disease, deadly cancers, insulin resistance, inflammation, neurological disorders, adverse outcomes in pregnancy, and increased risk for mortality. Expert recommendations for vitamin D intake differ between governmental agencies and practice guidelines from medical societies due to differences in the definition of vitamin D deficiency, insufficiency and sufficiency based on serum 25-hydroxyvitamin D [25(OH)D] concentrations. In addition, separate health promotion bodies also provide targeted recommendations for the prevention of specific disorders such as reducing risk for developing some cancers and autoimmune diseases. We review and provide perspectives regarding various recommendations from the Institute of Medicine (IOM, United States) and Health Canada, the European Food Safety Authority (EFSA), the Scientific Advisory Committee on Nutrition (SACN; United Kingdom), the World Health Organization, the Endocrine Society and other expert groups by life stage as a guide intended for clinician use.