Vitamin D and Health

1. Introduction
Background
1.1 Vitamin D is synthesised in the skin by the action of sunlight containing ultraviolet B (UVB) radiation.
Skin synthesis is the main source of vitamin D for most people. Dietary sources are essential when
exposure to sunlight containing the appropriate wavelength is limited.
1.2 The Committee on Medical Aspects of Food and Nutrition Policy (COMA) set Dietary Reference Values
(DRVs) for vitamin D in 1991 (DH, 1991). COMA did not set a Reference Nutrient Intake (RNI 7 ) for
groups in the population considered to receive adequate sunlight exposure because it was assumed
that, for most people, the amount of vitamin D produced by exposure to UVB radiation in the summer
would provide enough for their needs during winter.
1.3 Current UK Government advice is that a dietary intake of vitamin D is not necessary for individuals
living a ‘normal lifestyle’. Only certain groups of the population, who are at risk of vitamin D
deficiency, are advised to take a daily supplement: pregnant and breastfeeding women (10 µg/400 IU),
infants and children aged under 4y (7-8.5 µg/17.5-21 IU); adults aged 65y or above (10 µg/400 IU);
those with limited exposure to the sun (e.g., if they cover their skin for cultural reasons or are
housebound) (10 µg/400 IU) and women and children of Asian origin (10 µg/400 IU). The DRVs for
vitamin D were reviewed and endorsed by COMA in 1998 (DH, 1998).
1.4 Although the current recommendations for vitamin D are based on bone health, it has been suggested
that vitamin D may have a role in other health outcomes, which include reducing the risk of cancers,
cardiovascular disease (CVD), infectious diseases and autoimmune diseases.
1.5 The evidence on vitamin D and health was previously considered by the Scientific Advisory Committee
on Nutrition (SACN) in 2007 (SACN, 2007). In its position statement ‘Update on Vitamin D’ SACN
concluded that there was insufficient evidence, at that time, to reconsider the existing COMA DRVs for
vitamin D and that the evidence on the relationship between vitamin D status and chronic disease,
other than the metabolic bone diseases rickets and osteomalacia, was insufficient to draw
conclusions.
1.6 In October 2010, SACN agreed to review the data on vitamin D because a significant amount of new
evidence had accumulated since its previous considerations, including: results from research
commissioned by the Food Standards Agency (FSA); a detailed report published by the Institute of
Medicine (IOM) in the United States (US) on Dietary Reference Intakes for Calcium and Vitamin D
(IOM, 2011) 8 ; and numerous studies on vitamin D and various health outcomes.
Terms of Reference
1.7 The SACN Working Group on Vitamin D (WG) was established in 2011 to consider whether the current
DRVs for vitamin D intake, set by COMA in 1991, were still appropriate to ensure vitamin D adequacy
of the UK population in the context of current lifestyles and public health advice (e.g., to stay out of
the sun and to wear sunscreen).
7 The amount of a nutrient that is sufficient to meet the needs of 97.5% of the population.
8 Draft report published in 2010.
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