What to Know About Vitamin D and COVID-19

Vitamin D is an important nutrient your body needs to build and keep your bones strong, among other benefits. Sunlight is the main source -- your skin absorbs the sun’s ultraviolet rays and turns them into vitamin D.

But many people are deficient, or don’t get enough. This is especially true if you’re older, don’t eat healthy foods, or have a darker skin tone. And those low levels may raise your risk of severe COVID-19 if infected. Here’s what you need to know.

Vitamin D and COVID-19

While vitamin D boosts your immune system and eases inflammation, experts say more research is needed on its antiviral properties.

One study found that people with low levels of vitamin D had a 7.2% chance of testing positive for COVID-19. Another found that high levels of vitamin D might lower your risk for severe COVID-19 infection, especially if you’re a Black person. The study included over 3,000 people whose vitamin D levels were tested within 14 days before they got a COVID-19 test. Black people who had just enough vitamin D in their blood -- just over the normal limits -- were two times more likely to test positive than those who had even higher vitamin D levels.

But another report suggests higher levels of vitamin D don’t lower risk of viral infection, hospitalization, or severity of COVID-19. Researchers looked at more than 1 million people of European ancestry from 11 countries. They also included people with a gene mutation that allows them to have naturally high levels of vitamin D.

And a third study found that giving vitamin D to hospitalized patients with moderate to severe COVID-19 didn’t help their condition or reduce their hospital stay.

Vitamin D and Other Conditions

Not getting enough vitamin D may lead to or worsen these health problems:

All these can raise your risk for severe COVID-19 if infected.

Research shows that obesity and diabetes are linked to low levels of vitamin D. They’re also associated with higher death rates or severe COVID-19 symptoms.

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How to Get More Vitamin D

More sunlight and foods rich in vitamin D are the best ways. Try to get 15-20 minutes of sunlight, three days a week. And eat foods like:

  • Oily fish (like salmon or sardines)
  • Red meat
  • Egg yolks
  • Foods with vitamin D added

Supplements are also an option. Ask your doctor how much vitamin D you need before taking them. If you overdo it, you may have symptoms like:

  • Nausea
  • Increased thirst and urination
  • Poor appetite
  • Constipation
  • Weakness
  • Confusion
  • Ataxia, a neurological condition that causes you to slur or stumble
WebMD Medical Reference Reviewed by Michael W. Smith, MD on June 11, 2021

Sources

SOURCES:

Medscape: “High Vitamin D Levels May Not Protect Against COVID-19.”

University of Chicago Medicine: “Study suggests high vitamin D levels may protect against COVID-19, especially for Black people.”

JAMA Network: “Association of Vitamin D Levels, Race/Ethnicity, and Clinical Characteristics With COVID-19 Test Results.”

Journal of the American Medical Association: “Effect of a Single High Dose of Vitamin D3 on Hospital Length of Stay in Patients With Moderate to Severe COVID-19: A Randomized Clinical Trial.”

Clinical Medicine Journal: “Does vitamin D deficiency increase the severity of COVID-19?”

Cleveland Clinic: “Vitamin D Deficiency,” “42% Percent of Americans Are Vitamin D Deficient. Are You Among Them?”

PLOS Medicine: “Vitamin D and COVID-19 susceptibility and severity in the COVID-19 Host Genetics Initiative: A Mendelian randomization study.”

Harvard Health: “Do vitamin D, zinc, and other supplements help prevent COVID-19 or hasten healing?”

Mayo Clinic: “Can vitamin D protect against the coronavirus disease 2019 (COVID-19)?”

NHS: “Vitamin D.”

Biomolecules: “Emerging Role of Vitamin D and its Associated Molecules in Pathways Related to Pathogenesis of Thrombosis.”

Dermatoendocrinology: “Sunlight and Vitamin D.”

CDC: “People with Certain Medical Conditions.”

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