Will a vitamin D ‘mega dose’ ward off coronavirus?


If you need a clearer example of how quickly research is moving when it comes to coronavirus, take a look through the discussion around vitamin D.

On May 9, The Independent said: “Coronavirus: Scientists dismiss ‘very misleading’ claims that ‘mega doses’ of vitamin D can protect against disease”.

Just 10 days later, the same reporter, Matt Mathers, penned another story, this one under the headline: “Coronavirus: Low vitamin D levels linked to greater risk of contracting disease, suggests research”.

While not exact opposites, it does demonstrate the moving target which is reporting on the ever-evolving health story and the scientific efforts to end the lockdown and protect us from Covid-19.

Other media outlets have also reported on the conflicting messaging around vitamin D. Mail Online was 10 days behind The Independent in its coverage of “mega doses”, writing on May 19 that “Scientists say claims ‘mega doses’ of vitamin D can protect against coronavirus are ‘not true’ as they slam ‘very misleading’ reports on social media”.

Metro has been similarly down on vitamin D. It opted for the headline: “Large doses of vitamin D won’t do anything to help with coronavirus”.

But then The Spectator reported that a vitamin D deficiency may lead to people being more susceptible to Covid-19 in their “The growing evidence on vitamin D and Covid” story.

So is it true that a “mega dose” of the vitamin offers some protection from the deadly virus? And how do the stories fit with advice around whether to take vitamin D supplements?


At the moment there is no evidence that a “mega dose” of vitamin D will offer protection, but that doesn’t mean you should avoid vitamin D. And spare a thought for the journalists reporting on this story because, like many aspects of the Covid-19 response, research is shifting the dial by the day.

The newspapers are correct that a “mega dose” would not be beneficial. In fact, in some cases taking vitamin D can be damaging, for example, for people with kidney problems.

The vitamin is produced in the skin from UVB sunlight exposure and can help calcium to get from the gut to bones, as well as supporting the immune system through a number of immune pathways involved in fighting SARS2COV.

Recent studies have confirmed the pivotal role of vitamin D in viral infections. But the jury is out on whether vitamin D can offer some protection from Covid-19. According to health website WebMD, there are eight clinical trials registered to look into it. A Trinity College Dublin study published in the Irish Medical Journal in May found associations between vitamin D levels and Covid-19 and inspired the researchers to call on the Irish government to change their recommendations.

They found that countries at lower latitude and typically sunny places, such as Spain and northern Italy, had low concentrations of vitamin D and high rates of vitamin D deficiency. These countries also experienced the highest infection and death rates in Europe early in the pandemic.

The northern latitude countries of Norway, Finland and Sweden have higher vitamin D levels despite less UVB sunlight exposure, due to food and supplements. These Nordic countries have lower Covid-19 infection and death rates. The correlation between low vitamin D levels and death from Covid-19 is statistically significant, they discovered.

It should be noted that there may be other reasons for this discrepancy – the countries have taken different stances to lockdown and testing, and the authors of the study accept that “it is likely unknown factors will exist”.

While the scientists continue to do more research, the NHS has stressed that there is “no evidence that vitamin D reduces the risk of coronavirus”.

But that doesn’t mean that topping up on vitamin D is a bad idea, with the lockdown meaning less time outside there is a greater chance of deficiency as is common at the end of a winter spent cooped up indoors.

The message from the health service is keep it in moderation and don’t expect it to keep you free of Covid-19. Stick to social distancing for that.