Vitamin D was in the headlines today, with many papers reporting that a quarter of all toddlers are deficient in the nutrient and that childhood rickets is on the rise. The vitamin plays several important roles in the body, including regulating the balance of nutrients needed for strong, healthy bones.
The vitamin has fallen under the spotlight as Chief Medical Officer for England, Professor Dame Sally Davies, is reportedly contacting health professionals to highlight the need to prescribe vitamin D supplements to at-risk groups. There are already extensive guidelines on circumstances where people should take vitamin D supplements, but the move seems designed to increase use of the pills, which are available on prescription, or even free to individuals with a raised risk of deficiency.
An independent advisory committee is also researching and reviewing current recommendations on vitamin D, but the results of this extensive analysis are not expected until early 2014.
While vitamin D deficiency may have increased in recent years, rickets is still a rare condition. That said, it is entirely preventable and vitamin D supplementation can be of great importance to at-risk groups such as toddlers and young children.
What is vitamin D and why do we need it?
Vitamin D plays an essential role in maintaining good health. It has several important functions, including helping to regulate the amount of calcium and phosphate in the body. These substances are needed to keep bones and teeth healthy.
Without adequate vitamin D, bones can become thin, brittle and misshapen. In extreme cases this can lead to rickets in children, a condition involving a softening of the bones that can lead to fractures and deformity. In adults softening of the bones is usually called osteomalacia, and may cause pain and muscle weakness.
Vitamin D has many other important roles in the body including regulating cell growth, neuromuscular and immune function, and reduction of inflammation. Even years after its discovery, there is still ongoing research examining the various other functions vitamin D might perform in the body.
According to the Scientific Advisory Committee on Nutrition (SACN) – a group of experts that advises the government about all aspects of nutrition – some evidence suggests that vitamin D may be important in preventing other diseases including cancer, cardiovascular disease and multiple sclerosis, although it points out further research is needed before any definite conclusions can be drawn.
How can I get vitamin D?
The best source of vitamin D is sunlight on the skin. The vitamin forms under the skin in reaction to a type of ultraviolet ray called UVB. UVB rays are more powerful in the summer, and experts advise exposing the skin to regular, short periods of sun during the summer months, without sunscreen, which blocks UVB rays. However, it is important to ensure that the skin does not burn.
Vitamin D is also found in a small number of foods but it is difficult to obtain enough vitamin D from diet alone. Good sources of vitamin D include oily fish (such as salmon and sardines), eggs, cheese and meat. In the UK, all margarines and infant formula milks are fortified with vitamin D. It is also added to other foods such as breakfast cereals, soya and some dairy products, but usually only in small amounts.
Breastfed babies get their vitamin D from their mother’s breastmilk, which makes it especially important that breastfeeding women have adequate vitamin D levels of their own.
Vitamin D is also available in supplement form. Women and children participating in Healthy Start can get free supplements containing vitamin D. Some doctors sell supplements or supply them free of charge to those not eligible for Healthy Start.
Who needs vitamin D supplements?
The current advice is that most people should be able to get all the vitamin D they need by getting enough sun and eating a healthy balanced diet. However, the Department of Health says the following people may be at risk of vitamin D deficiency and recommends they take daily vitamin supplements:
- all pregnant and breastfeeding women
- all children aged six months to five years old
- all people aged 65 or over
- people who are not exposed to much sun – for example people who are housebound and those who cover up their skin for cultural reasons
- people who have darker skin, such as people of African Caribbean and south Asian origin. Their bodies are unable to produce vitamin D as easily
You can buy single vitamin D supplements at most pharmacies and supermarkets. Pregnant women who take vitamin D as part of a multivitamin should avoid supplements containing vitamin A (retinol), which can be harmful in pregnancy.
Can too much vitamin D be harmful?
The Department of Health says that taking 25 micrograms (0.025mg) or less a day of vitamin D supplements is unlikely to cause any harm.
Is rickets really on the rise?
Yes. In 2007 SACN published an update paper on vitamin D which, it said, highlighted “the prevalence of low vitamin D status throughout the UK population and the re-emergence of rickets in certain subgroups”.
However, while it would appear that a relatively high proportion of children do not get enough vitamin D, rickets is still a rare disease in the UK and there is certainly not an epidemic of the condition, as might be supposed by reading some news articles. That said, the condition is entirely preventable, and so there is a need to ensure parents and children have access to vitamin D supplements wherever appropriate, such as through the Healthy Start scheme.
What will happen next?
Last year the government launched a review of vitamin D supplementation, which is due to report in the next few years. In the meantime, Dame Sally is reportedly contacting health professionals to ensure they offer advice on vitamin D supplementation to those at risk, so that they can avoid health problems associated with deficiencies of this important nutrient.