A 2021 study published in the journal Nutrients found people who drink at least one cup of coffee a day may have a lower risk of contracting COVID-19 than those who don't. For the study, researchers at Northwestern University's Feinberg School of Medicine analyzed data from 37,988 people in the U.K. Biobank, a large-scale biomedical database and research resource. Researchers analyzed the participants' eating and drinking habits from 2006 to 2010, including how often they consumed coffee, tea, processed meat, red meat, fruit, vegetables, and oily fish, and coupled that with COVID-19 testing data from 2020. Ultimately, 17 percent of study participants tested positive for the virus through a PCR (polymerase chain reaction) test.
After crunching the numbers, the researchers found that people with "habitual consumption" of at least one cup of coffee a day had a 10 percent lower risk of contracting COVID-19 than their less-caffeinated peers. The researchers also discovered that eating vegetables and being breastfed as a baby reduced people's risk of contracting the virus. Processed meat was also linked to a higher risk of COVID-19, although eating red meat didn't seem to increase a person's risk. (Related: What Is the COVID-19 Mortality Rate?)
"Coffee consumption favorably correlates with inflammatory biomarkers" that are linked to severe forms of COVID-19 and death from the virus, the researchers wrote, adding, "taken together, an immunoprotective effect of coffee against COVID-19 is plausible and merits further investigation."
However, they stopped short of saying that coffee actually protects people against COVID-19.
So, Should You Drink Coffee to Ward Off COVID-19?
Infectious disease experts agree that it's hard to say coffee will actually lower your risk of COVID-19. "It is an association that needs more follow up and understanding of the mechanism," says infectious disease expert Amesh A. Adalja, M.D., a senior scholar at the Johns Hopkins Center for Health Security. But, "coffee does contain certain compounds that may have an impact on the immune system and immunity," he says. (See: All the Health Benefits of Drinking Coffee)
Richard Watkins, M.D., an infectious disease physician in Akron, Ohio, and a professor of medicine at the Northeast Ohio Medical University, agrees. "It might be a coincidence," he says. "But caffeine might have an effect on reducing inflammation caused by COVID." Still, Dr. Watkins adds, that's "purely speculation."
It's also possible that your coffee drinking habits and COVID-19 aren't directly linked. "It may be that these behaviors identify a group of people who, for one reason or another, may be more cautious about their health," says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine. For example, coffee consumption has also been linked to an increased likelihood of sticking to your fitness goals, and research found that exercising regularly is one of the best things you can do to reduce your risk of COVID-19. "It's an interesting association, but I did reflect on the fact that, if there might be a causal association, I'm well protected," he says.
Doctors stress the importance of continuing to follow known ways of lowering your risk of COVID-19, such as getting vaccinated, and not relying on coffee alone. "If people want to fully protect themselves against COVID, I would supplement their coffee with a vaccine," Dr. Adalja says. And, of course, to stay safe this summer amid COVID-19 concerns, social distancing and disinfecting personal belongings is another way to minimize risk.
The information in this story is accurate as of press time. As updates about coronavirus COVID-19 continue to evolve, it's possible that some information and recommendations in this story have changed since initial publication. We encourage you to check in regularly with resources such as the CDC, the WHO, and your local public health department for the most up-to-date data and recommendations.