Do you need to take vitamin D?

What does vitamin D do?

Vitamin D helps the body absorb calcium and phosphorus from foods. These nutrients are important for keeping our bones, teeth and muscles healthy.

Vitamin D is sometimes called the sunshine vitamin because it’s made in our skin when exposed to summer sunlight.

Even if you eat plenty of calcium-rich foods such as reduced-fat dairy and green leafy veg, your body still needs enough vitamin D to absorb and use that calcium properly.

Vitamin D also supports our immune system and heart health.

• Discover more about foods to help boost your immune system

What are the symptoms of vitamin D deficiency?

People with low vitamin D levels may feel more tired and get infections more often. In more severe cases, bones can become soft (osteomalacia) and fragile (osteoporosis), and muscles can weaken.

This increases the risk of pain, fractures and falls – particularly as we get older. In children, vitamin D deficiency can lead to rickets, a condition that affects bone growth.

A blood test measures vitamin D levels by checking the amount of 25-hydroxyvitamin D (25-OHD), which is the main form of vitamin D found in the blood.

More than 50nmol/L of 25-OHD is sufficient vitamin D for most people. Levels below 25nmol/L puts you at risk of soft bones and weak muscles.

A 2025 UK Government survey found that nearly 1 in 5 adults aged 19 to 65 have low vitamin D levels, putting them at risk of deficiency.   

How do you get vitamin D? 

There are a few ways you can get vitamin D. An estimated 80 to 90 per cent of vitamin D is produced in our skin during the summer months (April to September in the UK). The other 10 to 20 per cent comes from food.

Getting vitamin D from the sun

Vitamin D produced in your skin from sunshine can be stored in body fat and muscle. Your body can then use this in winter months when there's not enough sunlight to make it.

How much you have in store will depend on various factors, including:

• your age
• your skin colour (darker skin needs longer exposure to make vitamin D)
• the amount of time you spend outside
• how often you apply sunscreen and the level of SPF
• your clothes and how much skin they cover.

For many people in the UK, vitamin D stores will not reliably last throughout winter (October to March), so you'll have to rely on dietary sources or supplements.

You do not have to sunbathe to make vitamin D. Strong sunlight can burn skin, so it's important to balance making enough vitamin D with being safe in the sun.

Daily exposure to summer sunlight on your face, arms or legs is important for making vitamin D, but do not stay out long enough to burn. The NHS lists ways to be safe in the sun, including spending time in the shade between 11am and 3pm.

Getting vitamin D from your diet

Only a few foods are natural sources of vitamin D. These include oily fish, egg yolks, lean red meat, liver and certain mushrooms.

Some foods are also fortified with vitamin D, such as breakfast cereals and fat spreads.

However, even a well-balanced diet is unlikely to provide sufficient vitamin D in the winter months.

The following table lists foods that are considered high in vitamin D and how much they contain:

• Learn more about the foods high in vitamin D 

Should you take a vitamin D supplement?

As vitamin D is only found in a few foods, the government advises that everyone in the UK aged 4 years and above takes a 10-microgram (mcg), which is equivalent to 400IU, vitamin D supplement every day between October and March.

This is because we do not make sufficient vitamin D in our skin during the winter months.

Some people may also be advised to take a daily 10mcg vitamin D supplement all year round, such as:

• adults over 65 years
• children aged 1 to 4 years
• those who have little or no sun exposure – for example, people who cover their skin or spend long periods indoors
• those who have darker skin pigmentation.

What strength vitamin D should you take in winter?

The suggested strength of vitamin D for most people is a daily supplement providing 10mcg (400IU).

Supplements containing vitamin D3 (cholecalciferol) are the most effective at raising levels of 25-OHD in the blood, but may not be suitable for people following a vegan diet as they often contain lanolin (from sheep’s wool), unless they’re labelled vegan or lichen-derived.

Vitamin D2 supplements are a plant-based alternative that may be more suitable for vegetarians and vegans. A doctor may prescribe higher-dose supplements in the short term to treat deficiency.

However, it’s important to know that high intakes can be harmful, and you should only take these under a healthcare professional’s supervision.

Taking excess vitamin D can cause too much calcium to build up and be harmful to your bones, kidneys and heart.

Can you take vitamin D with heart medication?

For most people, vitamin D supplements at recommended doses are safe to take alongside heart and blood pressure medicines, and statins too. Unlike some supplements, vitamin D does not routinely interfere with heart treatments.

However, it’s not advisable to take high doses unnecessarily. If you take several medications or have a heart condition, it’s sensible to check with your GP, pharmacist or cardiology team before starting supplements.

• Learn more about taking vitamins and supplements alongside heart medicines