Vitamin D: key points - ARCHIVED

• Vitamin D has an essential role in maintaining healthy bones and in many other physiological processes by maintaining the body's levels of calcium within a normal range.  Vitamin D deficiency causes bones to become soft and weak: a condition known as rickets in children, and osteomalacia in adults.
• Vitamin D is primarily synthesised in the skin as a result of exposure to sunlight; it is also absorbed in the gut from food and vitamin D supplements.
• A substantial proportion of the Scottish population is considered to be vitamin D deficient; it is recommended that everyone over the age of 1 year should consume 10 micrograms (µg) of vitamin D daily. 
• Vitamin D production is related to skin pigmentation, and paler-skinned individuals are able to synthesise vitamin D from sunlight more efficiently. This means that darker-skinned individuals are at particular risk of vitamin D deficiency.
• There is a mixture of observational and randomised controlled trial (RCT) evidence about the associations and effects of insufficient vitamin D on health and mortality, and of vitamin D supplementation. Some observational evidence suggests that insufficient vitamin D levels may be associated with an increased risk of cardiovascular disease, cancer and other chronic diseases, as well as all-cause mortality.  RCT evidence is largely restricted to elderly individuals and those with pre-existing chronic conditions. A meta-analysis of RCTs indicates that vitamin D supplementation could reduce cancer mortality risk, though did not show a significant effect on all-cause or cardiovascular mortality risk.
• There is uncertainty about what levels of vitamin D are optimal for health. It is possible that both too little and too much Vitamin D can cause negative health effects.