Vitamin D: key points

  • Vitamin D is essential for maintaining the body's levels of calcium within a normal range, and consequently has a role in maintaining healthy bones and in many other physiological processes. It is synthesised in the skin as a result of exposure to sunlight and is also absorbed from food in the gut.
  • Vitamin D deficiency causes bones to become soft and weak: a condition known as rickets in children and osteomalacia in adults.
  • Some observational evidence suggests that low vitamin D levels may be associated with an increased risk of cardiovascular disease, cancer and other chronic diseases, as well as all-cause mortality. It is unclear whether or not low vitamin D levels are a cause of increased mortality.
  • There have been few randomised controlled trials of vitamin D supplementation and those that have been performed have been largely restricted to elderly individuals or to those with pre-existing chronic conditions.
  • There is a lack of agreement at present about what concentration of vitamin D is optimum for health. It is possible that both high and low levels are associated with negative health effects.
  • Vitamin D production is related to skin pigmentation and paler-skinned individuals are able to synthesise vitamin D more efficiently. This means that darker-skinned individuals who move to the UK from sunnier climates are at particular risk of vitamin D deficiency.
  • It is recommended that everyone over the age of 1 year should consume 10 micrograms of vitamin D daily.¬†

Section updates:

  • This section was first published in September 2012 and was last reviewed in¬†September 2017.
  • The next review of the section is due to be carried out by September 2018.