Can vitamin D protect against COVID-19?

Getting lots of sun may be dangerous when it comes to skin cancer, but it may also help prevent COVID-19.

That’s because sunlight prompts the body to produce vitamin D, which plays a critical role in immune function, and which is why the vitamin is now in the spotlight with the coronavirus. There is a long-established link between nutrition and immune health. But when it comes to the coronavirus, scientists still don’t have a definitive answer on whether certain vitamins and minerals can help stave off an infection or make one less severe.

“And that’s because it’s such a new phenomenon,” one that researchers are learning more about every day, says Walter Willett, M.D., professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health. Nothing is known to prevent or cure COVID-19, the illness caused by the new coronavirus. However, “It’s not impossible” that essential vitamins and minerals could provide some benefits, he adds in a recent article in AARP magazine.

Previous research has shown that lower-than-recommended levels of certain vitamins and minerals can impair immunity to respiratory viruses and other pathogens. Nutrient deficiencies have also been linked to higher levels of inflammation and longer periods of recovery from illness.

A few recent studies suggest an even more direct connection between certain vitamins and minerals and COVID-19. One report published in the Journal of Endocrinological Investigation found an association between vitamin D deficiencies and higher mortality risks from COVID-19 among patients in Italy. Others, yet to be peer reviewed, have drawn similar conclusions.

“The bottom line here is that I don’t think anybody should be walking around with low levels or low intakes of important and essential micronutrients and minerals and vitamins at any time, but especially if they’re potentially going to be infected with coronavirus,” Willett says. “It’s just basically practicing good preventive nutrition to begin with.”

The nutrient gaining the most traction among scientists studying COVID-19 is vitamin D. The vitamin is found in some foods; it’s also a hormone our bodies make when ultraviolet rays from sunlight strike the skin. Many know about vitamin D for its part in bone health.

Data from countries where vitamin D deficiency is common show higher cases of COVID-19 infection and more serious health consequences from the illness, including death, says June McKoy, M.D., associate professor of medicine at Northwestern University Feinberg School of Medicine. This correlation has prompted scientists to further explore whether vitamin D has any protective qualities against SARS-CoV-2, even while other published reports dispute the link.

RISK TIED TO LOW LEVELS OF D
One population most at risk for vitamin D deficiency — people who have darker skin color — is the same group that is being hit disproportionately hard by COVID-19 in the U.S. Hospitalization rates and deaths among Black Americans for COVID-19 are significantly higher than for their white peers. The same trend is reflected in the data for children with COVID-19.

“What we’ve seen is that the virus might actually be making use of that deficit,” McKoy says.

What’s more, obesity, cardiovascular disease and type 2 diabetes — all risk factors for severe illness from COVID-19 — have been tied to low vitamin D levels.

So far, the research looking at vitamin D and COVID-19 is limited, but Willett says a number of studies are underway, so expect to see more data in the near future. In the meantime, if you are able to get outside for a few minutes a day, do it. The National Institutes of Health (NIH) says most people meet at least some of their vitamin D needs through exposure to sunlight.

Stay-at-home orders and lockdowns brought on by the coronavirus outbreak have made access to frequent sunlight harder for some people in recent months, leading many to “almost certainly have lower vitamin D levels than they would have normally this time of year,” Willett says. For this population, Willett recommends a supplement to keep levels in the recommended range. Just remember to talk to your doctor before taking any supplement, since there’s a potential it could interact with other medications.