The Importance of Vitamin D for Health

Reviewed: 25 October 2026. General information for adults; individual advice may differ.

Vitamin D and everyday nutrition

Vitamin D helps regulate calcium and phosphate, which are needed for bones, teeth and muscles. The skin can produce vitamin D when exposed to sunlight. Food sources include oily fish, egg yolks and fortified foods; check labels because fortification varies between products and countries.

UK guidance

The NHS gives a daily requirement of 10 micrograms (400 IU) for adults. It advises adults to consider a supplement containing 10 micrograms during autumn and winter. Some people at greater risk of deficiency may need a supplement throughout the year. Follow the NHS guidance relevant to your circumstances or advice from a healthcare professional.

European reference values

EFSA sets an adequate intake of 15 micrograms (600 IU) per day for healthy adults, including pregnant and breastfeeding women, assuming minimal vitamin D production from sunlight. This is a reference for dietary intake, not a recommendation that everyone take a 15-microgram supplement.

National recommendations can differ. Follow the public-health guidance for your country and seek individual advice when needed.

Reading supplement labels

Check the vitamin D amount per tablet or capsule and the recommended serving. The strength of a particular product is not a statement of everyone’s daily requirement. Avoid unintentionally combining several products containing vitamin D. High doses can be harmful; a clinician may prescribe a different dose for an individual medical reason.

For an example of product labelling, see the Vitamin D3 product ingredients and serving information. This link does not mean that the product’s serving is suitable for every reader.

When to seek advice

Persistent symptoms should be assessed by a healthcare professional rather than used to self-diagnose vitamin D deficiency. A clinician can decide whether testing or treatment is appropriate.

Official sources

• NHS: Vitamin D — daily requirements, supplements and safety
• EFSA: Dietary reference values for vitamin D