Vitamin D: what you need to know
Why is vitamin D important?
Vitamin D is important for healthy bones, muscles, and teeth. For example, we need vitamin D to absorb calcium and phosphorus from our food. These nutrients help our body to build and maintain bone.
Vitamin D may have other important roles in the body. For example, it’s thought to help keep our immune system strong. But we don’t know for certain.
Why would I need a vitamin D supplement?
Your body makes vitamin D when your skin is out in the sunlight. You can also get it from certain foods, including egg yolk, oily fish, and fortified cereals. But it’s difficult for most people in the UK to get enough.
In the UK, the sun is only strong enough to meet our Vitamin D needs from April to September. Food sources alone rarely give you enough Vitamin D.
The government advises that everyone in the UK should consider taking a daily supplement containing 10 µg (micrograms) of vitamin D from October to March. If you work indoors, you could also try taking a walk outside at lunchtime to boost your sunlight exposure.
Do I need to take vitamin D all year?
It’s especially important to take vitamin D supplements during autumn and winter. From April to September, you can still choose to take vitamin D supplements if you wish. But you normally get more exposure to the sun during these months.
Certain groups are at a higher risk of having low vitamin D. People from these groups should consider taking a supplement throughout the year.
- People with dark skin, who don’t make as much vitamin D from sunlight.
- People who don’t get much exposure to sunlight. This could apply if you don’t get outdoors much, or if you wear clothes that cover most of your skin.
Do babies and children need to take vitamin D too?
Babies who breastfeed should also have a daily supplement containing 8.5 to 10 µg (micrograms) of vitamin D, from birth up to 1 year old.
If your baby is on infant formula, they shouldn’t need a supplement as long as they’re taking at least 500ml a day. This is because the formula already contains added vitamin D.
All children aged 1 to 4 years should take a daily 10 µg vitamin D supplement throughout the year.
Do my vitamin D levels need to be tested?
You won’t usually need to have a blood test unless you have signs of deficiency.
- If you’re an adult, your doctor may ask to test your vitamin D levels if you have pain in your bones, or muscle weakness. This could be a sign of bone disease, like osteomalacia and osteoporosis.
- If your child has bone pain or problems with their growth, your doctor may ask to test their vitamin D. This could be a sign of rickets or softening of the bones.
Some people with vitamin D deficiency won’t have any symptoms. So you could consider taking a vitamin D supplement to make sure you’re getting enough.
Where can I get vitamin D supplements?
You can buy vitamin D supplements from supermarkets, pharmacies, and health food shops. Although you don’t need to take more than 10 µg (micrograms), products that provide up to 25 µg are suitable for most people.
Women who are pregnant or breastfeeding, and children aged 6 months to 4 years, may be able to get free vitamins on the ‘Healthy Start’ scheme.
Although the recommend doses will be suitable for most people, it’s important to take the dose that’s right for you. Speak to your doctor or pharmacist if you’re unsure.
You can’t predict when you might want to see a GP, but you can be ready for when you do. Our GP subscriptions are available to anyone over 18 and give you peace of mind, with 15-minute appointments when it suits you at no extra cost.
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Sources Sources
- Vitamin D and health. Scientific Advisory Committee on Nutrition, 2016
- Vitamin D. BDA - The Association of UK Dietitians. bda.uk.com, last reviewed August 2022
- Pike JW, Christakos S. Biology and Mechanisms of Action of the Vitamin D Hormone. Endocrinol Metab Clin North Am. 2017;46(4):815-843. doi: 10.1016/j.ecl.2017.07.001
- Wimalawansa SJ. Infections and Autoimmunity-The Immune System and Vitamin D: A Systematic Review. Nutrients. 2023;15(17):3842. doi: 10.3390/nu15173842
- Martens PJ, Gysemans C, Verstuyf A, Mathieu AC. Vitamin D's Effect on Immune Function. Nutrients. 2020;12(5):1248. doi: 10.3390/nu12051248.
- Government dietary recommendations. Government recommendations for energy and nutrients for males and females aged 1 – 18 years and 19+ years. Public Health England, 2016
- Vitamin D: supplement use in specific population groups. Recommendation 7. NICE Guidance. nice.org.uk, last updated August 2017
- Vitamin D deficiency in adults. Diagnosis. When should I suspect or test for vitamin D deficiency? NICE Clinical Knowledge Summaries. cks.nice.org.uk, last revised January 2022
- Vitamin D deficiency in children. Diagnosis. When should I suspect or test for vitamin D deficiency? NICE Clinical Knowledge Summaries. cks.nice.org.uk, last revised January 2022
- Statement for PHE and NICE on vitamin D supplementation during winter. Public Health England. gov.uk, published 28 November 2020
- Safety considerations when using Vitamin D. Specialist Pharmacy Service. sps.nhs.uk, last updated September 2022
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