Vitamin D

Vitamin D can be produced by the body after exposure to sunlight. However, in the UK where sun exposure can often be minimal, many of the population have a vitamin D deficiency and require supplements. A deficiency in vitamin D can leave you feeling lethargic, depressed, weak, and susceptible to illness.


Patient information leaflet for Vitamin D replacement

Getting enough vitamin D is crucial for healthy bones and teeth, deficiency in children can lead to a condition called rickets, where the bones are weak, then soften, this leads to bone deformity (with bowlegs). In adults, even low levels of vitamin D can increase your risk of osteoporosis, or thinning of the bones. This along with our aging process in the decline of bone protective hormones can increase the risk of breaking a bone.

But vitamin D is important for much more than bone health. Vitamin D may play a role in:

How to get vitamin D

Vitamin D comes from sunlight and even for fair skin and winter months we should still be outside enough. The sunlight must fall directly on to bare skin (through a window is not enough). Too much exposure to the sun’s rays can be damaging i.e. Sunburn can increase the risk of skin cancer.

You can also get some Vitamin D from foods that either contain it naturally or have it added to them.

Or take replacement therapy.

How much vitamin D do I need?

Vitamin D is sometimes known as the ‘sunshine vitamin’: The natural type of vitamin D is produced in your skin when you’re exposed to sunlight, and we should get 80% of our Vitamin requirement this way.

However, in the UK, sunshine isn’t strong enough to allow you to make your own vitamin D especially in the winter. So it’s now recommended that everyone over 1 year old take 10 micrograms (400 International Units) a day from October to March.

Certain groups of people are at higher risk of low vitamin D, and will require all year-round replacement:

  • Are pregnant or breastfeeding.
  • Are aged 1-4 years.
  • Are over 65 (older adults are less efficient at producing vitamin D).
  • Have little exposure to sunlight, because you:
    • Are housebound/confined indoors for long periods.
    • Cover your skin for cultural reasons.
  • Have darker skin, because your body is not able to make as much vitamin D from sunlight.
  • There are certain medical conditions, that you GP or specialist services may recommend that you take a replacement all year round i.e. certain gut (bowel), kidney or liver diseases.

Vitamin D deficiency symptoms

Many people have no vitamin D deficiency symptoms or may experience vague symptoms such as tiredness or general aches, due to this Vitamin D deficiency is often missed. The diagnosis is more easily recognised in severe deficiency with some of the classical (typical) symptoms and bone deformities.

Vitamin D deficiency symptoms in adults

  • General tiredness, vague aches and pains and a general sense of not being well.
  • In more severe deficiency (known as osteomalacia), there may be more severe pain and weakness in bones and muscles (the latter is noticed when experiencing difficulty in climbing stairs or getting up from the floor or a low chair or having a waddling gait when walking.
  • Bones can be painful to moderate pressure often more noticeable in the ribs or shin bones, but it is not uncommon for people to have a hairline fracture in the bone which is causing tenderness and pain. Other areas that bone pain often occurs is the lower back, hips, pelvis, thighs, and feet.

Who gets vitamin D deficiency?

This can occur for various reasons:

  • People who get very little sunlight on their skin are at risk of vitamin D deficiency. This is more of a problem in the more northerly parts of the world (including the UK) where there is less sun. In particular:
    • People who stay inside a lot. For example, those in hospital for a long time, or housebound people.
    • People who cover up a lot of their body when outside.
    • The strict use of sunscreen may increase the risk of vitamin D deficiency, particularly if high sun protection factor (SPF) creams (factor 15 or above) are used. However, there is no evidence that the normal use of sunscreen does cause vitamin D deficiency in real life. Everyone, should always be protected from the harmful effect of the sun’s rays. 


  • Elderly people are unable to produce as much vitamin D. This leaves older people more at risk of vitamin D deficiency.
  • People who have darker skin are not able to make as much vitamin D.
  • Some medical conditions can affect the way the body handles vitamin D. People with Crohn’s diseasecoeliac disease, and some types of liver and kidney disease, are all at risk of vitamin D deficiency.
  • Rarely, some people without any other risk factors or diseases become deficient in vitamin D. It is not clear why this occurs. It may be due to a subtle metabolic problem in the way vitamin D is made or absorbed. So, even some otherwise healthy, fair-skinned people who get enough sun exposure can become deficient in vitamin D.
  • Vitamin D deficiency can also occur in people taking certain medicines, i.e. carbamazepinephenytoinprimidone, barbiturates and some anti-HIV medicines.

Not enough dietary vitamin D

Vitamin D deficiency is more likely to occur in people who follow a strict vegetarian or vegan diet, or a non-fish-eating diet.

Vitamin D:

This is given intramuscular in the upper outer quadrant of buttock (the Dorsogluteal) at 300,000units given every 6 months, ideal with some evidence of Vitamin D deficiency. Ideally a calcium and kidney function should have been undertaken recently and are in the normal levels, discuss this with your practitioner,

How common is vitamin D deficiency?

A lack of vitamin D is very common. One survey in the UK showed that about 1 in 5 adults and about 1 in 5 children in the UK have low vitamin D levels. More people have low vitamin D levels in the winter and spring because of less exposure to sunlight.