Sir David Davis and Matt Ridley write on how correcting Britain’s Vitamin D deficiency could save thousands of lives


As published in the Sunday Telegraph:

As we face six tough months of curfews, isolation and economic misery, with vaccines a distant hope, testing struggling to control the virus, and the hospitalisation rate once again rising, it’s surely time to try anything reasonable to slow the pandemic down. There is one chemical that is known to be safe, known to be needed by many people anyway, known to have a clinically proven track record of helping people fight off respiratory diseases, and is so cheap no big firm is pushing it: vitamin D. It is not a silver bullet, but growing evidence suggests that it might help prevent Covid turning serious in some people.

In May, arguments on the link between Vitamin D deficiency and its association with poor Covid outcomes started to gather pace. That month, the Health Secretary’s attention was drawn to two studies showing a strong association between the incidence and severity of Covid-19 with vitamin D deficiencies in the patients. Vadim Backman of Northwestern University, one of the authors of one of those studies, said about healthy levels of vitamin D that “Our analysis shows that it might be as high as cutting the mortality rate in half.”

When asked to look at the evidence, Matt Hancock perfectly reasonably handed the question to Public Health England to answer. They attempted to analyse the statistical data and came up unconvinced. The problem is that a correlation is not a proof of cause and effect, and a correlation (albeit a very strong one) is all that we had at that point. Or almost all that we had.

The gold standard of medical research is the randomised controlled trial. Back in May, we had no such test for vitamin D and Covid-19. Now we do. The world’s first randomised control trial on vitamin D and Covid has just been published. The results are clear-cut. The trial, which took place in Spain at the Reina Sofía University Hospital, involved 76 patients suffering from Covid-19. Fifty of those patients were given vitamin D. The remaining 26 were not. Half of those not given Vitamin D became so sick that they needed to be put on intensive care. By comparison, only one person who was given Vitamin D requiring ICU admission.

Put another way, the use of Vitamin D reduced a patient’s risk of needing intensive care 25-fold. Two patients who did not receive Vitamin D died. And while the sample is too small to conclude that Vitamin D abolishes the risk of death in Covid patients, it is nonetheless an astonishing result, and corresponds with Prof Backman’s assertion that correcting vitamin deficiency might cut mortality by half. The Government should now act on this latest evidence.

Vitamin D cannot be obtained from a normal diet, but is synthesised by summer sunshine. It is unusual among vitamins in being deficient in much of the British population especially towards the end of winter and especially among at-risk groups such as the elderly, obese, and black and minority ethnic groups.

Vitamins are useless as medications in people who already have sufficient of them; they only work in those who are deficient. So this is not a call to boost a vitamin that is already present in sufficient quantity in most people. Britain has a national policy already of wanting to redress the widespread winter deficiency of vitamin D.

We have two possible courses of action. The first, as we called for back in May, is for people to up their intake of Vitamin D through supplements. The NHS providing free Vitamin D supplements to at risk groups is the easiest and most straightforward option. Vitamin D supplementation is cheap – it costs less than a penny a pill – and readily available. If you allocated this to the identified comorbidity risk group it would cost £45 million: to these, plus to every ethnic minority citizen, about £200 million, to every obese person somewhat more. These costs are trivial rounding errors by comparison with the costs of lockdown.

The second option would be to do what the Nordics do and fortify food with vitamin D, including bread, flour and milk. The ideal approach would be to undertake both options at the same time, along with a public health education campaign.

We have good reason to think vitamin D supplementation will help reduce mortality from Covid-19 and we know it can reduce the incidence and severity of the other acute respiratory illnesses. With hospitals already facing pressures from influenza during the winter months, any way of reducing this strain should be taken up. This will no doubt save thousands of lives in any second wave. There is now no reason not to act.