How can I prevent vitamin D deficiency?
Vitamin D and sunlight
For a fair-skinned person, it is estimated that around 20-30 minutes of sunlight on the face and forearms around the middle of the day 2-3 times a week is sufficient to make enough vitamin D in the summer months in the UK. For people with darker skin and for the elderly, the amount of time needed to be exposed to sunlight to make enough vitamin D can be much more than this. The sunlight has to fall directly on to bare skin (through a window is not enough). Too much exposure to the sun's rays can be damaging. Sunburn should be avoided at allcosts (mainly because it can increase your risk of skin cancer).
For six months of the year (October to April), much of western Europe (including 90% of the UK) lies too far north to have enough UVB rays in sunlight necessary to make vitamin D in the skin. So, many people in the UK are at risk of not getting enough vitamin D unless they get it in their diet.
Some people are more at risk of vitamin D deficiency and so are recommended to take vitamin D supplements of 10 micrograms (400 International Units) routinely. These include all pregnant and breast-feeding women, all babies and young children aged 6 months to 5 years, people aged 65 years and over, and people who are not exposed to much sun.
In addition, a doctor may advise routine vitamin D supplements for people with certain gut (bowel), kidney or liver diseases, for people prescribed certain medicines and for certain people with darker skin.
In the UK, it's now recommended that everyone aged 4 years or over should be getting at least 10 micrograms (400 International Units) a day of vitamin D. That means that even people who don't fall into one of the at-risk groups above might want to consider taking a supplement in the winter months (from October to April).
You can buy vitamin D supplements at pharmacies. In the UK they are also available on prescription to certain groups of people. If you are unsure as to whether you should be taking a regular supplement of vitamin D, or what the appropriate dose is, then your doctor, pharmacist, health visitor or midwife can advise.
Did you find this information useful?
- Vitamin D and health; Scientific Advisory Committee on Nutrition (July 2016)
- Evaluation, Treatment, and Prevention of Vitamin D Deficiency; Endocrine Society Clinical Guideline (July 2011)
- Vitamin D - advice on supplements for at risk groups; Chief Medical Officers of the UK, February 2012
- Bolland MJ, Avenell A, Grey A; Should adults take vitamin D supplements to prevent disease? BMJ. 2016 Nov 23 355:i6201. doi: 10.1136/bmj.i6201.
- Vitamin D: increasing supplement use among at-risk groups; NICE Public Health Guidance, November 2014
- Sunlight exposure: risks and benefits; NICE Guidance (February 2016)
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