Sunshine Pills… Yes Please! Why Is Vitamin D So Important?

This week I had my Vitamin D tested. My level was 24nmol/L, which is very low and I am now classed as being Vitamin D deficient. I join approximately half of the UK population, who are also thought to be lacking in this important vitamin. It is essential for good health and healthy, strong bones.

When sunlight hits our skin, Vitamin D is made in the outer layer of our skin called the epidermis. In order for our body to be able to use it, it has to be changed in to an active form by our liver and then our kidneys. The active form of vitamin D is called calcitrol and it has one main role – to help us absorb the right amount of calcium. If we have low levels of Vitamin D, our gut has to work harder to absorb the calcium we need for our bones and this can lead to problems.

Sunlight is the main source of vitamin D. Dietary sources are limited, but small amounts can be found in eggs and oily fish such as salmon, sardines and mackerel. Fortified cereals and margarines also offer part of your recommended daily dose. In some countries, milk is fortified with Vitamin D, but this is not the case in the UK.

Hand with pen drawing the chemical formula of vitamin d

Sunshine is important for Vitamin D, but don’t forget that you need to enjoy your time in the sun safely. Try and avoid the sun during the hottest part of the day (between 11am – 3pm) or maximise your time to 20-30 minutes once or twice a week. Take care to wear a hat and sunglasses, and always use sun protection with a minimum SPF 15 and 4 stars.

In most of Western Europe, especially in the Winter months, the amount of sunshine we get falls far below the levels needed for the body to produce adequate amounts of Vitamin D. This means you are at risk if:

  1. You have darker coloured skin because the body finds it more difficult to make Vitamin D
  2. Your job means you are inside all the time
  3. You are under 5 or over 65 years old
  4. Culturally you have to cover up
  5. You are overweight
  6. You have other health problems, e.g. with your gut, liver or kidney which might affect your body’s ability to make or use the Vitamin D
  7. You are pregnant or breast feeding

With that list – it is not entirely surprising that most of us are low in vitamin D!

In adults, a prolonged low vitamin D level can lead to osteomalacia or ‘soft bones.’ You may feel tired, and develop bone pain especially in the lower back and hips. You might also notice muscle aches and pains or muscle weakness, especially when climbing the stairs or getting up from sitting on the floor. Your joints can also become painful. In extreme cases, it can lead to a change in the shape of your spine and fractures of your bones.

In children, a low Vitamin D can cause rickets, thankfully this is rare. Rickets is a painful condition that affects how bones grow and can cause ‘bow legs’ or ‘knock knees’ to develop. These children are at increased risk of fractures and tend to have poor growth and development.


All children aged between 6 months and 5 years should take a daily supplement of Vitamin D unless they are having more than 500mls of formula milk per day (which is fortified with vitamin D). Pregnant and breast feeding women are also at high risk of deficiency and must take daily supplements. Speak to your doctor or midwife if you have any questions.

Speak To Your Doctor

If you have noticed you are having any of the symptoms of vitamin D deficiency, or you feel you are one of the people at risk, speak to your doctor. They will ask about the symptoms you are having and they may examine you. It is likely they will carry out a blood test checking your Vitamin D level, along with your bone profile and they may also request other tests depending on what you have told them.

Once the results are back, they will discuss them with you. They will review your medical history and any other medications you are on, because in certain circumstances it isn’t safe to take higher doses. Rarely, there can be other reasons why you might have a low Vitamin D level or a low calcium level and if your doctor suspects this they may carry out further investigations.

As a guide a Vitamin D blood level of <30nmol/L is classed as deficient, a level of 30-50nmol/L is insufficient and 50-70nmol/L is considered adequate but ideally levels should be above 70nmol/L.

The most common treatment for a low Vitamin D level is high dose Vitamin D3 tablets – the dose can vary depending on your levels, but I tend to prescribe 50,000 IU once a week for 6 weeks. After ‘topping up’, it is important that you continue taking a maintenance of between 800 IU and 1000 IU otherwise your levels may fall again and any symptoms you had may return.

It is very rare that you can take too much vitamin D, so as long as you are taking your prescribed amounts I wouldn’t worry about overloading yourself.

Other Health Benefits?

There has been a lot in the media suggesting that Vitamin D can help to protect against developing breast and bowel cancer, or high blood pressure and heart disease. It has also been linked to being beneficial in diabetes, multiple sclerosis, dementia and depression. These have all been relatively small studies and no conclusive evidence has been found. It is likely that Vitamin D is protective to a certain degree, but there are many other factors that contribute. It is a small piece of a much larger puzzle.

Vitamin D is extremely important to our general health. Winter is almost upon us, and so my advice would be to speak to your doctor as soon as possible about getting your levels tested. You can then discuss with them the right dose of Vitamin D for you.