All About Vitamin D
What is Vitamin D?
Vitamin D is a vitamin that is needed for good health, growth and strong bones.Unlike other vitamins, we do not need to get vitamin D from food as the majority of this nutrient is made by our own bodies. It is made in the skin by the action of sunlight. This is useful because most foods contain very little or no vitamin D naturally and are often ‘fortified’ to make up for this.
Foods that contain vitamin D include:
-Oily fish (such as sardines, pilchards, herring, trout, tuna, salmon and mackerel) which is the best dietary source of vitamin D or cod liver oil.
-Fortified foods (this means they have vitamin D added to them). There is little or no vitamin D in UK milk and dairy products. Only infant formula milk and margarine have statutory vitamin D supplementation in the UK.
Ultraviolet B (UVB) rays in sunlight convert cholesterol in the skin into vitamin D. For a fair skinned person, it is estimated that around 20-30 minutes of sunlight on the face and forearms around the middle of the day 2-3 times a week is sufficient to make enough vitamin D in the summer months in the UK. However, for people with darker skin and the elderly, the amount of time needed exposed to sunlight to make enough vitamin D can be much more than this. For six months of the year (October to April), much of western Europe (including 90% of the UK) lies too far north to have enough UVB rays in sunlight necessary to make vitamin D in the skin. So, many people in the UK are at risk of not getting enough vitamin D unless they get it in their diet.
Why do we need vitamin D?
Vitamin D plays an essential role in the absorption of calcium and phosphorus via the gut. These nutrients are needed to keep bones healthy and strong. Hence, vitamin D is really important for strong and healthy bones. Vitamin D is also important for muscle growth and regeneration and for general health.
Who gets vitamin D deficiency?
Vitamin D deficiency means that there is not enough vitamin D in your body. It isvery common. A recent UK survey showed that more than half of adults in the UK are vitamin D deficient. From October to April, about 1 in 6 people have a severe deficiency. Most affected people either don’t have any symptoms, or have fatigue or vague aches and pains, and are unaware of the problem.
This can occur in three situations:
- The body has an increased need for vitamin D: growing children, pregnant women, and breast-feeding women need extra vitamin D because it is required for growth.
- The body is unable to make enough vitamin D: this occurs in people who stay indoors a lot such as elderly housebound patients and office workers, darker skinned people and in certain medical conditions (Crohn’s disease, Coeliac disease, some liver and kidney diseases).
3.Not enough vitamin D is being taken in the diet: this is more likely to occur in people who follow a strict vegetarian or vegan diet, or a non-fish-eating diet.
What are the symptoms of vitamin deficiency?
In babies and children;
- Children with severe deficiency may have soft skull or leg bones which can sometimes look curved (bow-legged). They may also complain of bone pains, (frequently the legs), and muscle pains or muscle weakness. This condition is known as rickets.
- Poor growth with height being affected more than weight. Affected children might be reluctant to start walking.
- Tooth delay. Children with vitamin D deficiency may be late teething as the development of the milk teeth has been affected.
- Children with vitamin D deficiency are more prone to infections especially chest/respiratory related infections as breathing can be affected due to weak chest muscles and a soft ribcage.
- Babies with severe vitamin D deficiency can get muscle cramps, breathing difficulties and can occasionally lead to seizure. These problems are related to the associated low calcium levels. These need urgent hospital treatment.
- Rarely, an extremely low vitamin D level can cause weakness of the heart muscle (cardiomyopathy).
- Some people complain of a 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 also weakness.
- Bones can feel painful to moderate pressure (often more noticeable in the ribs or shin bones). Not uncommonly, people have a hairline fracture in the bone which is causing tenderness and pain. Bone pain often also occurs in the lower back, hips, pelvis, thighs and feet.
How is vitamin D deficiency diagnosed?
It may be suspected from a person’s medical history, symptoms, or lifestyle, however simple blood test will check vitamin D levels.
How is vitamin D deficiency treated?
The treatment is to take vitamin D supplements and this comes as an injection or an oral medication. The dose will depend on a person’s levels, sometimes people need a high (treatment) dose initially followed by a maintenance dose.
How can you prevent deficiency?
We now know that certain groups of patients are prone to vitamin D deficiency. The following groups of patients are now advised to take regular vitamin D supplementation.
- All pregnant and breast-feeding women should take a daily supplement containing 10 micrograms of vitamin D.
- All babies and young children aged 6 months to 5 years should take a daily supplement containing vitamin D in the form of vitamin drops. However, those babies who are fed infant formula will not need vitamin drops until they are receiving less than 500ml of infant formula a day, as these products are fortified with vitamin D. Breast-fed babies may need to receive drops containing vitamin D from one month of age if their mother has not taken vitamin D supplements throughout pregnancy.
- People aged 65 years and over and people who are not exposed to much sun should also take a daily supplement containing 10 micrograms of vitamin D.
- Some patients with certain gut, kidney or liver diseases, people prescribed certain medicines (carbamazepine, phenytoin, primidone, barbiturates and some anti-HIV medicines)and people with darker skin.
If you are unsure as to whether you need to take vitamin D supplements or need to have your levels checked, please speak to us here at Coyne Medical and we will happily advise.
Dr Vanessa Ní Churrain
Private GP, Parsons Green, Fulham