Vitamin D is in the news again, and while the experts squabble over it, I'm off to buy myself some supplements. The chief medical officer for England has told GPs like me to advise those at risk to take supplements. And since half the adult population of the UK is lacking vitamin D in the winter months and deficiency is being linked to a growing list of health problems, I can't see a good reason not to take a small multivitamin a day – at least until the sun comes out. I'll stick to the recommended daily amount as you can have too much of a good thing, even vitamins.
Vitamin D is essential for bone growth and health, and deficiency can cause rickets in the young and a condition called chondromalacia in adults. You wouldn't think rickets still existed in the UK but it probably never went away and is increasingly recognised as a cause of fractures in susceptible children.
Recently two parents, Rohan Wray and Chana al-Alas, were accused of murdering their four-month-old baby who died two years ago from sudden infant death syndrome (Sids, also known as cot death). The baby, Jayden, was found to have multiple injuries and the parents were accused of shaking the baby to death. But pathologist Dr Irene Scheimberg, based at Royal London Hospital, found evidence of rickets in Jayden at postmortem and the judge directed the jury to acquit.
Since that tragic case, Scheimberg says she has discovered vitamin D deficiency in eight further cases of Sids and in 30 cases of children who have died of various causes and had postmortems. A colleague of hers, Dr Marta Cohen, working in Yorkshire has also found vitamin D deficiency in 18 out of 24 cases of Sids and in 45 babies under the age of one, who died of other causes. Both doctors are calling for further investigation into the implications of vitamin D deficiency and highlighting the need to be aware of rickets in cases of Sids, which can be mistaken for non-accidental injury.
This adds weight to those calling for widespread vitamin D supplementation in the UK. Advice from the chief medical officer for England, Sally Davies, was for at-risk groups – which includes pregnant and breastfeeding women, children aged six months to five years old, people aged 65 or over, people who are not exposed to much sun (the housebound, those who cover up their skin for cultural reasons and people who have darker skin, whose bodies are unable to produce vitamin D as easily) – to take vitamin D. But there have been calls to introduce supplements for all the population in Scotland, because of high levels of multiple sclerosis which may be linked to vitamin D deficiency. Ryan McLaughlin, 13, launched a campaign, Shine on Scotland, in response to his mother's diagnosis of MS, while Professor George Ebers of the Nuffield department of clinical neurosciences at Oxford University believes the evidence is now good enough to justify dosing the entire population with vitamin D. Professor George Ebers of the Nuffield Department of Clinical Neurosciences at Oxford University is quoted, saying that he believes the evidence is now good enough to justify dosing the entire population with vitamin D. Last month, his team published evidence of a link between MS and an inherited tendency that leads to vitamin D deficiency.
Scotland's chief medical officer, however, Sir Harry Burns, says in the same article he thinks there needs to be "broader scientific consensus" before change is considered. He warns that dietary supplements can cause harm and that we need to wait for good randomised studies in large populations. He wants to wait for the conclusions of a review of the evidence by the UK government's scientific advisory committee on nutrition in 2014.
But Ebers says that is too long. He reflects that there was evidence to support recommending folic acid supplementation for all pregnant women to prevent problems like spina bifida, many years before the public health authorities backed it.
Bruce Hollis, professor of paediatrics and biochemistry at the Medical University of South Carolina, agrees, insisting there's no point waiting for a large randomised trial because it's unlikely to ever happen. He says it would be hard to attract funding for an expensive, large scale trial as drug companies would be unlikely to make a profit on cheap vitamin supplements.
The best source of vitamin D is sunlight on the skin. Vitamin D is also found in a small number of foods (oily fish, eggs, cheese and meat) but it is difficult to get enough vitamin D from diet alone. In the UK, all margarines and infant formula milks are already fortified with vitamin D and it is also added, in small amounts, to other foods such as breakfast cereals, soya and some dairy products,. Breastfeeding mothers need adequate vitamin D levels of their own to ensure their babies get enough.
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.
While the experts continue to debate, we may all be well advised to take a daily vitamin D supplement and expose our skin to whatever weak winter sunshine we can.
