Vitamin D Deficiency
Vitamin D is important for good health, growth and strong bones and may also help to prevent other
diseases such as cancer, diabetes and heart disease. A lack of vitamin D is very common. Vitamin D is
mostly made in the skin by exposure to sunlight. A mild lack of vitamin D may not cause symptoms but
can cause generalised aches and pains and tiredness. A more severe lack can cause serious problems
such as rickets (in children) and osteomalacia (in adults), described below. Treatment is with vitamin D
supplements. Some people are more at risk of vitamin D deficiency, and so are recommended to take
vitamin D supplements routinely. These include all pregnant women, breast-fed babies, children under
5, and people aged 65 and over. Also, people who do not get much exposure to the sun, people with
black or Asian skin types, people who do not go out in the sun and people with certain gut, liver or
kidney diseases. We have checked our own patients and found that 9/10 adults of South Asian origin
are vitamin D deficient and something like 60% of our white patients are vitamin D deficient. Most
people present with aches and pains and tiredness.
What is vitamin D?
Vitamins are a group of chemicals that are needed by the body for good health. Foods that contain
vitamin D include the following though many foods do not contain much vitamin D and exposure to the
sun is a better source of vitamin D than foods. Vitamin D is a fat-soluble vitamin. Most foods contain
very little vitamin D naturally , though some are fortified (enriched) with added vitamin D. Foods that
contain vitamin D include:
Oily fish (such as sardines, pilchards, herring, trout, tuna, salmon and mackerel).
Egg yolk.
Fortified foods (this means they have vitamin D added to them) such as
margarine, some cereals, infant formula milk.
Our main source of vitamin D is that made by our own bodies. 90% of our
vitamin D is made in the skin with the help of sunlight.
Ultraviolet B (UVB) sunlight rays convert cholesterol in the skin into vitamin D. Darker skins need more
sun to get the same amount of vitamin D as a fair-skinned person. The sunlight needed has to fall
directly on to bare skin (through a window is not enough). 2-3 exposures of sunlight per week in the
summer months (April to September) are enough to achieve healthy vitamin D levels that last through
the year. Each episode should be 20-30 minutes to bare arms and face. This is not the same as
suntanning; the skin simply needs to be exposed to sunlight.
So, vitamin D is really important for strong bones. In addition, vitamin D seems to be important for
muscles and general health. Scientists have also found that vitamin D may also help to prevent other
diseases such as cancer, diabetes and heart disease.
Who gets vitamin D deficiency?
Vitamin D deficiency means that there is not enough vitamin D in the body. Broadly speaking, this can
occur in three situations:
1. Increased need for vitamin D
Growing children, pregnant women, and breast-feeding women.
2. Situations where the body is unable to make enough vitamin D
People who get very little sunlight on their skin are also at risk of vitamin D deficiency. This is more of a
problem in the most northern parts of the world where there is less sun. In particular:
People who stay inside a lot or cover up when outside or use strict
sunscreen
People with pigmented (dark coloured) skins and elderly people
Some medical conditions can affect the way the body handles vitamin D.
People with Crohn's disease, coeliac disease, and some types of liver
and kidney disease, are all at risk of vitamin D deficiency.
Vitamin D deficiency can also occur in people taking certain medicines examples include: Carbamazepine, Phenytoin, prim done, barbiturates and some anti-HIV
medicines
3. 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.
How common is vitamin D deficiency?
It is very common. This is why we recommend a regular supplement to our patients. A recent survey in
the UK showed that more than half of the adult population in the UK had low vitamin D. This level is
found to be greater in people who have dark skin. In the winter and spring about 1 in 6 people has a
severe deficiency. It is estimated that about 9 in 10 adults of South Asian origin may be vitamin D-
deficient. Most affected people either don't have any symptoms, or have vague aches and pains, and
are unaware of the problem. 80% of our Asian patients have been found to be deficient and 60% of our
white patients have found to be deficient.
What are the symptoms of vitamin D deficiency?
Symptoms of vitamin D deficiency are tiredness or general aches. Because symptoms of vitamin D
deficiency are often very vague, the problem is often missed.
How is vitamin D deficiency diagnosed?
Vitamin D deficiency can be diagnosed by a blood test. However, on balance if you have dark skin and
live in the UK you should take supplements. It may be suspected from your medical history, symptoms,
or lifestyle. A simple blood test for vitamin D level can make the diagnosis.
WHAT WE RECOMMEND – Your doctor will advise you if you have deficiency or insufficient
vitamin D. If you have a minor level of vitamin D deficiency we recommend patients buy vitamin D
tablets equivalent to 10ug or 12.5ug. Most are made from vegetables. If you have been found to be
deficient we would recommend you stay on this dose for life as treatment is often needed long-term
because the cause of the deficiency, such as dark skin or not enough sunlight, is unlikely to be
corrected in the future. We have observed that it takes at least 6 months taking regular vitamin D for
symptoms to resolve and the level of vitamin D to return to normal. It should be noted that if you have
severe deficiency the doctor may recommend that you take a higher dose of vitamin D for a limited time,
often equivalent to 25ug for the first 3 months. Please discuss this with your own doctor. We
recommend that patients buy vitamin D tablets as we are unable to prescribe vitamin D without calcium
on the NHS and calcium prescriptions have been associated with increased kidney stones and it is for
this reason that we recommend that our patients buy vitamin D.
Maintenance therapy after deficiency has been treated
The dose needed for maintenance maybe lower than that stated. We advise patients to buy 10ug and
take 2 a day. When the body's stores of vitamin D have been replenished. maintenance treatment is
often needed long-term, to prevent further deficiency in the future. This is because it is unlikely that any
risk factor for vitamin D deficiency in the first place, will have completely resolved. The dose needed for
maintenance may be lower than that needed to treat the deficiency.
Cautions when taking vitamin D supplements
Care is needed with vitamin D supplements in certain situations:
1. If you are taking certain other medicines that can interact such as Digoxin (for an irregular
heartbeat – atrial fibrillation), Thiazide or diuretics (water tablets).
2. If you have medical conditions such as kidney stones, some types of
kidney disease, liver disease or hormonal disease.
3. Vitamin D should not be taken by people who have high calcium levels.
4. You may need more than the usual dose if taking certain medicines
such as Carbamezapine, Phenytoin. HRT or barbiturates.
NB Multivitamins are not suitable for long-term high-dose treatment because the
vitamin A which can be harmful in large amounts.
Are there any side-effects from vitamin D supplements?
It is very unusual to get side effects from vitamin D if taken in the prescribed dose. However, very high
doses can raise calcium levels in the blood. This would cause symptoms such as thirst, passing a lot of
urine, nausea or vomiting.
Prognosis (outlook) in vitamin D deficiency?
The outlook for vitamin D deficiency is usually excellent. Both the vitamin levels and the symptoms
generally respond well to treatment. However, it can take time (months) for symptoms to resolve and for
bones to recover. Generally after 6 months of using Vitamin D tablets the patient feels a lot better and
symptoms have improved. This does not mean you need to stop taking the medication. Vitamin D
supplementation is for life.