Vitamin D study to assess role in protecting Black population from COVID

A University of Chicago researcher wants to study thousands of people to test the relation between vitamin D and boosting the immune system to fight viruses.

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The University of Chicago Medicine located at 5841 S. Maryland, in the Hyde Park neighborhood.

UChicago Medicine in Hyde Park. Researchers there are studying how vitamin D levels affect how well African Americans can fight off COVID-19.

Tyler LaRiviere/Sun-Times file

University of Chicago researchers want to determine whether vitamin D supplements can help African Americans better fight COVID-19.

Dr. David Meltzer, chief of hospital medicine at UChicago Medicine and lead researcher of two upcoming studies, said Black people typically have lower levels of vitamin D than whites, though the health consequences are not well known. 

Newly published research led by Meltzer found a lower risk of infection, particularly for Black people, when vitamin D levels are increased higher than what experts now deem sufficient for overall health. 

In the wake of that data study, Meltzer is recruiting volunteers for two human trials to better understand that relationship between immune system and boosting vitamin D with supplements. Meltzer wants to hone in on the racial distinctions and see if boosting vitamin levels reduces either the risk of becoming infected or the severity of illness. 

The benefit of taking vitamin D to ward off COVID-19 has sparked debate in the medical community. Some doctors caution too much of the vitamin can be detrimental to health. Nonetheless, attention around coronavirus-related research last year has driven sales of vitamin D supplements during the pandemic. 

Meltzer argues there are unanswered questions about vitamin D as it relates to the overall health of Blacks, particularly for fighting infections. One benefit of Vitamin D is bone strength, a factor that can help prevent osteoporosis, but previous research suggests even though vitamin D levels are lower in Blacks than whites, bone density isn’t dramatically different between the racial groups, Meltzer said. 

What isn’t well understood, he adds, is the role Vitamin D levels in Black people plays in boosting the immune system, another benefit of vitamin D. 

“The effects on the immune system … have been much more difficult to define,” Meltzer said in an interview. “Even if one has enough vitamin D to be good for bone health, that doesn’t mean one has the right amount of vitamin D to be good for immune function.” 

Sources of vitamin D include supplements and fatty fish. Exposure to the sun also help the body create its own vitamin D, but that also can mean low levels during winter in cold-weather locations like Chicago. 

One U. of C. study, to be overseen by the U.S. government, will conduct lab tests of people taking low doses of supplements as well as the highest safe levels. The other study will include self-reporting online. In each trial, half of those taking part will receive vitamins, others will receive placebos. Meltzer hopes to attract 2,000 people for each trial and will be recruiting over the next two months. The studies are open to all, though researchers want a racially diverse group.

Those interested in taking part in the study, which is backed by the National Institutes of Health, can email or call 773 834-8620. For the online study, go to

Meltzer acknowledges the research will likely be finished sometime after the COVID-19 pandemic is waning, at least according to current predictions. 

“We’re doing this not just for the current pandemic but also for the next one,” he said.


“We’re doing this not just for the current pandemic but also for the next one,” Dr. David Meltzer says of his research of vitamin D and COVID-19.


Brett Chase’s reporting on the environment and public health is made possible by a grant from The Chicago Community Trust.

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