Vitamin D: what you need to know

Dr Luke Powles
Associate Clinical Director, Health Clinics Bupa Global and UK
12 December 2023
Next review due December 2026
Taking a daily vitamin D supplement is a simple but important way to maintain your health. But why is vitamin D important, and what do you need to know before taking it? Here, I explain all.
woman walking outdoors looking at her mobile phone

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.

Bupa offers digital GP services through different routes to suit you. If you have Bupa health insurance you have unlimited access to Digital GP appointments through the Digital GP app (in partnership with Babylon). If you don't have health insurance, our remote private GP service is available to anyone who wishes to book a self-pay video appointment with a private GP via Bupa Health Clinics.

Dr Luke Powles
Dr Luke Powles
Associate Clinical Director, Health Clinics Bupa Global and UK



Atiya Henry, Health Content Editor at Bupa UK

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