How Does a Vitamin D Deficiency Affect COVID-19?

by Kroger Health Staff

Last Updated: December 14, 2020

Dozens of studies are underway to learn whether vitamin D may help lessen the severity of COVID-19 infections or help protect against COVID-19 complications.

Vitamin D—also known as the sunshine vitamin-–helps regulate the immune system. A deficiency of vitamin D is associated with increased susceptibility to infection. It is prevalent among Hispanic and African-Americans, those with hypertension and a body mass index of 30 or higher. About 35 percent of Americans are vitamin D deficient, and most don’t realize it.

Vitamin D is found in fatty fish like salmon, egg yolks and fortified dairy products, and orange juice. But exposing your skin to sunlight is the best source of vitamin D. The recommended dietary allowance (RDA) for men and women (age 19-70) is 600 IU each day or 15 micrograms (mcg.) Men and women 71 years and older should consume 800 IU each day or 20 mcg each day.

Several recent studies from around the globe have explored the relationship between vitamin D deficiency and COVID-19:
  • Recent research published in JAMA showed a relationship between vitamin D deficiency and a higher risk of COVID-19. The study looked at 489 patients who had their vitamin D levels measured in the past year and found the risk for testing positive for COVID-19 was 1.77 times greater for patients who were likely vitamin D deficient.
  • Another study published in The Journal of Clinical Endocrinology & Metabolism found similar results. According to the study, most COVID-19 patients at a hospital in Spain were found to be deficient in vitamin D. More than 80% of 216 COVID-19 patients at the Hospital Universitario Marques de Valdecilla had a vitamin D deficiency. The study also noted men had lower vitamin D levels than women. Those with vitamin D deficiency also had a higher prevalence of cardiovascular disease and hypertension and were hospitalized longer for COVID-19, the study noted.
  • Researchers in the U.K. evaluated COVID-19 cases and vitamin D levels across 20 European countries. The study found countries with lower average vitamin D levels generally had higher numbers of COVID-19 cases and deaths.
While research suggests that low vitamin D may affect how severe COVID-19 will be, it’s not yet known if vitamin D could be a treatment. It is also not known if maintaining healthy vitamin D levels will help you avoid the virus.

In the meantime, more research is still needed to learn what role, if any, vitamin D might have in the prevention and treatment of COVID-19. However, maintaining vitamin D levels is important in general, not just in relationship to COVID-19. Until more is known, the best way to prevent a COVID-19 infection is to follow CDC guidelines and practice social distancing, wear a mask, and wash hands frequently.

Disclaimer: The information in this story is accurate as of its publication. However, the situation surrounding COVID-19 is ever-evolving. We are working to keep our stories up-to-date as changes occur, but we also encourage everyone to check news and recommendations from the CDC, WHO, and their local authorities.