For a number of reasons, many people aren’t getting enough vitamin D to stay healthy. This is called vitamin D deficiency. You may not get enough vitamin D if:
You don’t get enough sunlight. Your body is usually able to get all the vitamin D it needs if you regularly expose enough bare skin to the sun. However, many people don’t get enough sunlight because they spend a lot of time inside and because they use sunscreen. It’s also difficult for some people to get enough vitamin D from the sun during the winter.
You don’t take supplements. It’s very difficult to get enough vitamin D from the foods you eat alone.
Your body needs more vitamin D than usual, for example if you’re obese or pregnant.
Are certain people more likely to have vitamin D deficiency?
There are some groups of people that are more likely to have vitamin D deficiency. The following people are more likely to be lacking in vitamin D:
People with darker skin. The darker your skin the more sun you need to get the same amount of vitamin D as a fair-skinned person. For this reason, if you’re Black, you’re much more likely to have vitamin D deficiency that someone who is White.
People who spend a lot of time indoors during the day. For example, if you’re housebound, work nights or are in hospital for a long time.
People who cover their skin all of the time. For example, if you wear sunscreen or if your skin is covered with clothes.
People that live in the North of the United States or Canada. This is because there are fewer hours of overhead sunlight the further away you are from the equator.
Older people have thinner skin than younger people and this may mean that they can’t produce as much vitamin D.
Infants that are breastfed and aren’t given a vitamin D supplement. If you’re feeding your baby on breast milk alone, and you don’t give your baby a vitamin D supplement or take a supplement yourself, your baby is more likely to be deficient in vitamin D.
People who are very overweight (obese).
What are the symptoms of vitamin D deficiency?
Some people may not have any symptoms of vitamin D deficiency and still be deficient.
The symptoms of vitamin D deficiency are sometimes vague and can include tiredness and general aches and pains. Some people may not have any symptoms at all.
If you have a severe vitamin D deficiency you may have pain in your bones and weakness, which may mean you have difficulty getting around. You may also have frequent infections. However, not everyone gets these symptoms.
If you think you may have vitamin D deficiency, you should see your physician, or have a blood test to check your vitamin D levels.
How do I know if I’m deficient in vitamin D?
The way doctors measure if you’re deficient in vitamin D is by testing your 25(OH)D level, but most doctors just call this a vitamin D test. Getting this blood test is the only accurate way to know if you’re deficient or not. Please see our testing page for more information.
Holick MF. Vitamin D and Health: Evolution, Biologic Functions, and Recommended Dietary Intakes of Vitamin D. In Vitamin D: Physiology, Molecular Biology and Clinical Applications by Holick MF. Humana Press, 2010.
Plum LA and Deluca HF. The Functional Metabolism and Molecular Biology of Vitamin D Action. In Vitamin D: Physiology, Molecular Biology and Clinical Applications by Holick MF. Humana Press, 2010.
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