People who are vitamin D deficient are nearly 60 percent more likely to test positive for coronavirus, a new study finds.
Vitamin D plays an important role in the immune system, boosting the health of T cells and macrophages, which fight infection.
Previous studies have noted a link between low vitamin D levels and higher rates of other respiratory disease, such asthma, tuberculosis and viral infections that attack the lungs.
While fringe theories eagerly promoted taking vitamin D as a potential preventive and even drew links between the vitamin and racial disparities, data to prove the connection has been scarce, and doctors warn that, even if it has some effect, the vitamin is not enough to protect you from coronavirus.
The new study, from the University of Chicago, is the first to show higher rates of COVID-19 in people who were recently vitamin-D deficient – within the year – before getting tested for coronavirus.
And those who had been vitamin D deficient, but got treated, were less likely to test positive for COVID-19 – but the study authors warn that it will take clinical trials to prove whether boosting levels of the vitamin will help prevent infection.
People who had low levels of vitamin D (far left) in the year before getting tested for coronavirus were 60% more likely to test positive for the virus (dark blue) compared to those with higher levels of the vitamin (right), new University of Chicago research found
To-date, more than 6.1 million Americans and 26 million worldwide have caught coronavirus.
The pandemic’s persistence has left the world desperate for treatments preventives, and particularly wishful for a quick fix.
Vitamin D deficiency is a tempting common thread connecting several groups at high-risk for getting coronavirus and becoming severely ill: elderly and obese people, and people of color.
Our primary source of vitamin D is sunlight. We absorb the vitamin from its rays through our skin.
Elderly people, among whom mobility issues are common, are more likely to be home and indoors, missing out on sunlight and the vitamin D it offers.
Higher levels of melanin in the skin of black and brown people make it more difficult for their bodies to absorb the vitamin.
To that end, the Chicago researchers studied the link between vitamin D and COVID-19 in a predominantly (68 percent) non-white group.
In total, vitamin D levels measured in blood draws within the year before undergoing a coronavirus test were ‘likely deficient’ in one quarter (25 percent) of the study group of nearly 500 people, according to the research, published Thursday in JAMA Network Open.
Among the group who had plenty of vitamin D, 12 percent tested positive for coronavirus.
Nearly 20 percent (19 percent) of those who had low levels of vitamin D tested positive.
It’s hardly proof that vitamin D can keep people from catching coronavirus, but the 60 percent difference in positive test rates suggests it may have some effect.
The results of the Chicago study run counter to those of a UK study published last month. It found no link between vitamin D ‘insufficiency’ (a less dramatic decrease in vitamin D levels) and coronavirus infection.
However, the blood samples used to determine that difference were taken 10-14 years before the study was conducted (and stored in the UK Biobank).
Whether or not vitamin D supplements should be taken to reduce coronavirus risks is controversial, but getting enough of the ‘sunshine vitamin’ plays a role the immune system’s ability to fight infection and keep inflammation from running getting out of control (file)
In the intermeaning years, says Dr David Meltzer, co-author of the University Chicago study, those people may have been treated, and it’s difficult to know whether or not they were vitamin D insufficient (or deficient) at or around the time of their coronavirus tests.
In his study the link between vitamin D deficiency and COVID-19 was ‘stronoger. the more recently the vitamin D level was measured,’ Dr Meltzer told DailyMail.com.
‘Could it be real? I think it’s possible,’ he added.
‘Scientifically, we would like to have a randomized trial to show whether vitamin D reduces the. risk of COVID-19 or improves outcomes, but we have to decide what to do for ourselves.’
Dr Meltzer himself is doing his best to get some daily sunshine, as well as taking vitamin D supplements.
Mayo Clinic experts recommend getting at least 600 IU of vitamin D a day, whether via sunshine or supplements. It’s generally considered safe to take up to 2,000 IU a day, but anyone with or at risk of kidney disease should not do so, as an overload can harm kidneys, causing stones and other problems.
Taking too much can also elevate calcium levels, cause a host of digestive issues and may lead to bone loss in some cases. Dr Meltzer adds that scientists still don’t know what, exactly, is the optimal level of vitamin D, or how much is too much.
As for the racial disparity in COVID-19 cases, Dr Meltzer says that vitamin D is not the answer, but it might well play a role, considering his study’s findings and the approximately two-fold higher rates of vitamin D deficiency among black Americans compared to the general population.
‘There are almost certainly many reasons why African American and Hispanic populations shoulder a heavier burden of COVID-19 including being in essential jobs’ – that require them to go to work outside the home, rather than limiting exposures – ‘and access to health care,’ Dr Meltzer said.
‘It would be a mistake to assign all the differences we’re seeing [in rates of COVID-19] to a biological explanation, but it would probably also be a mistake to exclude tthe possibility that biological explanations aren’t a part of it, and that interventions like vitamin D supplements might make a difference.’
But that remains to be determined for certain, and trials – including some out of the University of Chicago – are underway to attempt to answer those lingering questions of vitamin D’s protective power.