Can Eating a Plant-Based Diet Lower Your Risk of Developing Severe COVID-19?

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Getting vaccinated and masking up in crowded indoor spaces are some of the best ways to protect yourself against COVID-19. But new research suggests there's one surprising factor that may lower your risk of developing moderate-to-severe COVID-19: Eating a plant-based diet.

The study, which was published in June in BMJ Nutrition, Prevention & Health, analyzed survey data from health care workers from six countries (France, Germany, Italy, Spain, U.K., and U.S.) who had "substantial" exposure to COVID-19 patients. Of the group, 568 were diagnosed with COVID-19, and 2,316 were not.

Of the patients who were diagnosed with COVID-19, 138 developed "moderate-to-severe" COVID-19 (meaning, they had a fever, respiratory issues, low oxygen levels, among other things), while 439 had very mild or mild cases of the virus. After analyzing the data, the researchers discovered that those who followed a plant-based diet had a 73 percent lower risk of developing moderate-to-severe COVID-19 than their counterparts. Also worth noting: People who followed either a plant-based or pescatarian diet had 59 percent lower odds of developing a moderate-to-severe form of COVID-19. As for those who maintained a low-carb, high protein diet? They actually had greater odds of developing moderate-to-severe COVID-19. Overall, there was no link between a person's diet and whether they got infected with COVID-19 in the first place or how long their illness lasted. (Related: What to Do If You Think You Have COVID-19)

"Plant-based diets or pescatarian diets were associated with lower odds of moderate-to-severe COVID-19," concluded the researchers. "These dietary patterns may be considered for protection against severe COVID-19."

Currently, the U.S. Department of Agriculture's Dietary Guidelines for Americans recommends that people follow a mainly plant-based diet to lower the risk for heart disease, type 2 diabetes, obesity, and other health issues. The American Heart Association also suggests following a mostly plant-based diet for overall heart health. (Related: The Plant-Based Diet Benefits Everyone Should Know)

So, what's going on here? Study co-author Sara Seidelmann, M.D., Ph.D., assistant professor of clinical medicine at the Columbia College of Physicians & Surgeons, says that there may be something about eating a plant-based diet, in particular, that may help reduce the risk of severe COVID.

"Plants are abundant in micronutrients like vitamins A, C, E, and minerals — iron, potassium, magnesium," she says. "These nutrients can support our immune system since they play key roles in the production of antibodies, proliferation of lymphocytes [white blood cells], and reduction of oxidative stress." All of which can help increase your immune system's chances of fighting off a virus, such as COVID-19.

Plant proteins are high in fiber (vs. animal proteins that have no fiber) and help support and strengthen the gut microbiome, says Dr. Seidelmann. "Fiber becomes the food source of billions of microbes that support our immune function and protect us from foreign invaders," she adds. Research has linked a healthy gut with strong immune systems and the ability to better fend off pathogens. (Related: These Benefits of Fiber Make It the Most Important Nutrient In Your Diet)

Infectious disease experts are hesitant to say for sure that switching to a plant-based diet will help protect you from severe COVID-19. "It's hard to say anything definitive with nutritional studies because they are often many confounding issues," says infectious disease expert Amesh A. Adalja, M.D., a senior scholar at the Johns Hopkins Center for Health Security. "However, in general, there is a consensus that diet plays a major role in immune function as well as in the [gut] microbiome, which can influence the outcome of other diseases such as infections."

There might also be other variables in play here. For example, people who follow a plant-based diet may be more likely to exercise regularly, maintain a lower body weight, and be more mindful of health safety protocols — all of which can also lower your risk of severe COVID-19, says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine. (See also: Exercising Regularly Is One of the Best Ways to Lower Your Risk of Severe COVID-19)

"These people tend to be healthier in general," he notes. "Even once they are infected, their bodies may be in better shape and better able to handle the virus." See, eating a plant-based diet can lower inflammation in blood vessels, says Richard Watkins, M.D., an infectious disease physician and professor of internal medicine at the Northeast Ohio Medical University. But if your body is already inflamed (whether because of, say, the foods you eat or any medical conditions), it can make it that much harder for your immune system to quickly and efficiently take on a virus such as COVID-19 that causes bodily inflammation, adds Dr. Watkins. (On a similar note, did you know that coffee might actually help reduce any inflammation caused by COVID-19?)

People who are health-conscious also may be more likely to do things such as wear masks in public and social distance, which could lower the level of virus they encounter if they do happen to have an exposure, says Dr. Schaffner. "That could also reduce the risk of severe COVID," he adds.

Overall, though, experts say more data is needed to create a stronger link between diet and severe COVID-19. "It's important to continue to study the role of nutrition in this context as more data is amassing regarding the possible health benefits of pescatarian and vegetarian diets," says Dr. Adalja.

And in the meantime, doctors say there's no need to switch to a plant-based diet purely because of these findings. But (!!) they do point out that plant-based diets, in general, are recommended for good health. "It's clear that there is nothing more important than what we choose to eat every day," says Dr. Seidelmann. "Unless restricted by food allergy, fill your plate with whole plant foods like vegetables, fruits, whole grains, seeds, nuts, and legumes. It's the most important thing that you can do for your long-term health."

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.