Dr. Anthony Fauci, MD, the nation’s top immunologist and leading authority on COVID-19, says he takes vitamin D supplements, as well as vitamin C, to support a healthy immune system, Insider.com reports.

“If you’re deficient in vitamin D, that does have an impact on your susceptibility to infection. I would not mind recommending, and I do it myself, taking vitamin D supplements,” he said. “The other vitamin that people take is vitamin C because it’s a good antioxidant, so if people want to take a gram or so of vitamin C, that would be fine.”

Extensive evidence has linked vitamin D deficiency to greater risk of infection, particularly from respiratory diseases like COVID-19, and many people are susceptible to deficiency right now because of lack of sun exposure and other genetic factors, the Insider.com article says.

“That’s led many researchers to investigate the use of vitamin D supplements to help prevent or lessen the effects of the coronavirus. While the findings are somewhat contentious, since researchers don’t fully understand if vitamin D supplements can cause better health outcomes, studies have consistently linked vitamin D deficiency to greater risk of severe infection.

And many people are deficient in vitamin D, especially while sheltering indoors during the pandemic or in darker winter months, since our bodies naturally produce the nutrient in response to sunlight.