Does your vitamin D level play a role in your COVID-19 risk?

There’s no denying that vitamin D plays an important role in your immune system.

Vitamin D helps regulate your immune response. More specifically, it helps your body determine when it needs to send out its immune defenders… and how much of these defenders it needs to send out. It’s also known to make immune cells, like T-cells and macrophages, more effective.

Now, during a serious pandemic like we’re facing, we all want our immune systems to be as strong as possible. And it sounds like vitamin D could potentially help. But is there any evidence that vitamin D can reduce the risk and/or severity of COVID-19 specifically?

The answer is yes and no.

While there have never been any studies on vitamin D’s impact on COVID-19, there have been plenty of studies on vitamin D’s impact on respiratory infections in general. And the results of these studies are strong enough to make researchers in Ireland suggest that boosting your vitamin D intake right now might be a good idea.

The connection between vitamin D and viral respiratory infections

Researchers from The Irish Longitudinal Study on Ageing (TILDA) at Trinity College Dublin just released a report discussing vitamin D’s potential role in the COVID-19 pandemic.

In Ireland, just like in the U.S., a large chunk of the population is deficient in vitamin D. And researchers say that there’s plenty of previous research proving that this could make them more vulnerable to COVID-19.

Past research shows that vitamin D helps prevent respiratory infections. In fact, low vitamin D levels raise the risk of both respiratory diseases (like tuberculosis, asthma, and chronic obstructive pulmonary disease) and respiratory infections caused by bacteria and viruses.

Related: Overlapping respiratory infections means your doctor could mistakenly clear you of COVID-19

A recent analysis of the best existing studies on vitamin D’s role in viral respiratory infections like colds and flu found that taking vitamin D supplements significantly reduced the risk of developing one of these infections. In fact, people who took vitamin D supplements daily or weekly lowered their risk of having at least one acute respiratory infection from 60 percent to 32 percent.

Another recent scientific analysis found that people with low vitamin D levels were 64 percent more likely to develop community-acquired pneumonia. There’s also evidence that low vitamin D levels reduce lung function in general, which may mean a higher risk of COVID-19 complications.

On top of all that, there’s evidence that adequate vitamin D levels help your immune system respond better to all infections, respiratory or otherwise. Like I mentioned earlier, vitamin D helps manage your immune response and strengthens your immune cells.

Vitamin D also has an anti-inflammatory effect on your body. As you know, a lot of people live with chronic, low-grade inflammation… especially older adults, the people most at risk for COVID-19. When your body’s already in a consistent state of inflammation, your immune system gets used to this pre-existing state of inflammation and may not respond as effectively when an actual infection comes your way.

What to do about D during this crazy time

All this evidence was strong enough for Irish researchers to recommend that adults over age 50 take vitamin D supplements. But the fact is, many adults under age 50 could benefit from vitamin D supplementation as well.

Now, you can get vitamin D in foods like eggs, liver, and oily fish, as well as fortified foods like cereals and dairy products. But the biggest source of vitamin D by far is sun exposure. And there are plenty of people across all age groups that don’t get much sun, especially in northern climates. Plus, with new social distancing and quarantine guidelines, large segments of the population may be spending more time inside and getting even less sun then they normally do.

Related: The best time to take vitamin D

That’s why supplementation is a good idea. Vitamin D supplements are relatively risk-free, and the evidence shows they could provide extra immune support during this trying time.

Typically, I’d recommend getting your vitamin D levels tested before starting supplementation, but you don’t want to add any unnecessary strain to the healthcare system right now. There are companies that make at-home vitamin D testing kits (like this one from EverlyWell). So, that’s something to consider.

The minimum recommended amount of D3 per day is 600 IU. But depending on how low your levels are, you might need anywhere from 1,000 to 4,000 IU per day to get your levels up. That’s why it’s good to know your baseline vitamin D levels if possible. But most healthcare providers, including Dr. Michael Cutler, agree that taking a vitamin D supplement that’s 5,000 IU per day or less won’t cause you any harm.

Editor’s note: There are numerous safe and natural ways to decrease your risk of blood clots including the 25-cent vitamin, the nutrient that acts as a natural blood thinner and the powerful herb that helps clear plaque. To discover these and more, click here for Hushed Up Natural Heart Cures and Common Misconceptions of Popular Heart Treatments!


  1. Vitamin D could help fight off COVID-19 — MedicalXpress
  2. Vitamin D deficiency in Ireland– implications for COVID-19. Results from The Irish Longitudinal Study on Ageing (TILDA) — The Irish Longitudinal Study on Aging
  3. Can Vitamin D Lower Your Risk of COVID-19? — Healthline
  4. Vitamin D and the Immune SystemJournal of Investigative Medicine
  5. Vitamin D — Mayo Clinic
Jenny Smiechowski

By Jenny Smiechowski

Jenny Smiechowski is a Chicago-based freelance writer who specializes in health, nutrition and the environment. Her work has appeared in online and print publications like Chicagoland Gardening magazine, Organic Lifestyle Magazine, BetterLife Magazine,, and