Why Are Scientists Talking About Vitamin D to Help Fight COVID-19?

It’s no surprise why scientists are interested in studying vitamin D as a treatment tool for COVID-19, or its deficiency as a potential risk factor for serious illness from the respiratory disease that is caused by the novel coronavirus.

After all, vitamin D deficiency is common among many groups at high risk for COVID-19, including the elderly and people with obesity, diabetes, and high blood pressure, says Rose Anne Kenny, chair of medical gerontology at Trinity College in Dublin. Aging and obesity both reduce the ability of the skin to make vitamin D from exposure to the sun’s ultraviolet rays, Kenny says, and these diseases are associated with aging and carrying extra weight.

Vitamin D is known for aiding several essential body functions that, when compromised, may affect COVID-19 outcomes. “Vitamin D is best known for its effects on bone, but it also has important effects on the immune system,” says Adrian Martineau, PhD, a clinical professor of respiratory infection and immunity at Queen Mary University of London. According to the National Institutes of Health, vitamin D is also important for fighting inflammation and contributing to cell growth.

Vitamin D supports the ability of the innate immune system to mount a range of antiviral responses, including production of substances called antimicrobial peptides that are produced by white blood cells and the lining of the lung, Dr. Martineau says. These peptides have antiviral properties as well as antibacterial ones. Vitamin D also acts to dampen down potentially harmful inflammatory responses in the body that can be more active in people with health conditions such as obesity and diabetes, which are also risk factors for COVID-19, Martineau adds.