Vitamin D is synthesised in the skin by the action of UVB on 7-dehydrocholesterol. Adequate vitamin D levels are thought to have a protective effect, decreasing cancer melanoma risk and mortality.² People who are avoiding exposure to sunlight and using sunscreens assiduously can be at risk of vitamin D deficiency.

It is estimated that about 15 minutes of sunlight a day on unprotected skin (e.g. arms and face) is enough to meet the body’s vitamin D requirements. However, in the UK from mid-October until the beginning of April there is insufficient UVB for skin synthesis of vitamin D and so supplements should be considered.

NICE now recommends that all adults living in the UK should take a daily supplement containing 400 international units (IU) [10 micrograms] of vitamin D throughout the year.³ Pregnant and breastfeeding women eligible for the NHS Healthy Start scheme can obtain free vitamin preparations.