A diet rich in coffee and vegetables may reduce your COVID-19 risk

What do coffee and salad have in common? According to a new study published last month in the academic journal Nutrients, coffee consumption and eating vegetables as part of a balanced healthy diet may offer additional protection against COVID-19. 

The study was conducted by the Department of Preventive Medicine at the Feinberg School of Medicine at Northwestern University. It examined dietary data from participants of the UK Biobank from March 16, 2020, to Nov. 30, 2020.

The study was based on a questionnaire that asked participants how much they ate or drank when it came to cooked and raw vegetables, fresh and dried fruit, fish, red meats like beef or pork, and tea and coffee. What they found was that the 37,988 participants who had tested positive for COVID-19 may have followed patterns that affected both whether they got sick and how sick they got with coronavirus.

“A person’s nutrition impacts immunity, and the immune system plays a key role in an individual’s susceptibility and response to infectious diseases, including COVID-19,” said Marilyn Cornelis, associate professor of preventive medicine at the Northwestern University and a senior author of the study.

Coffee, veggies, and breast milk

So what does this mean for you? The study found that having one or more cups of coffee per day, compared to having less than one cup a day, was associated with a roughly 10% decreased risk of contracting COVID-19.

The Mayo Clinic, however, recommends drinking no more than four cups a day. Caffeine has been linked to bad health effects including high blood pressure.

The Northwestern University study also found that the consumption of around 0.67 servings per day of vegetables could also lower the risk of COVID-19, which is less than what the American Heart Association recommends for daily intake. This factor seemed to be paired with a reduced intake of meat in participants.

However, the study also found that “red meat consumption presented no risk, suggesting meat per se does not underlie the association we observed with processed meats.” In addition to these results, the study also found that participants who had been breastfed as babies had a 10% reduced risk of contracting COVID-19.

Of course, a healthy diet is not a substitute for vaccination, which the Centers for Disease Control and Prevention say is the most effective and proven way to prevent COVID-19 infections resulting in severe illness and death.

Inherent biases

It should be noted that the study used body-mass index as one of the factors in their analysis sample, which is an inaccurate and often misleading means of categorizing the fat-to-muscle ratio in individuals. It also identified a socioeconomic factor that was not elaborated on within the body of the study.

One of those factors is the fact that better-educated, employed, and white participants generally have better access to fresh vegetables, coffee, and better healthcare. Those identified as nonwhite, on other hand, had higher BMI levels, ate more red meat, and were in generally poorer health. The United Kingdom has been accused of having inequitable healthcare access, which in itself has been a field of study in recent years.

“Before relying on the results of a study, you should validate their results by identifying if a bias exists with how it was conducted, what it measured, what flaws or drawbacks exist from the methodology used, and more,” says Dr. Lily Adelzadeh, a board-certified dermatologist in Pleasanton, California.

The study also utilized a relatively small participant pool, isolated to England, so the study may not be applicable globally or might come up with unexpected, counterintuitive results. For example, Northwestern University’s study concluded that the “consumption of broccoli surprisingly increased COVID-19 mortality.”

“While a healthy and balanced lifestyle is important to boost your immune system and stave off any disease, you cannot rely on diet changes alone to offer protection from contracting a communicable disease,” said Dr. Sanjana Vig, an anesthesiologist and writer at The Female Professional. “It’s still important to visit your doctor for medical advice and to take care of any underlying conditions you already have”.