Ongoing Study Seeks Link Between Gut Microbiome and COVID-19 Severity

Close up of woman's hands with yogurt and berries on table

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Key Takeaways

  • A Rutgers University study is investigating the gut microbiome as a possible factor in the severity of COVID-19 symptoms.
  • The microbiome plays a large role in immune system health, but the specific impact is still largely unknown.
  • Increasingly popular probiotics and prebiotics may have a positive impact on the prevalence of healthy gut bacteria.

As the first doses of a COVID-19 vaccine are administered to Americans this week, our national attention has shifted away from trying to understand the coronavirus, instead focusing on finally beating it.

Given the hundreds of thousands of new daily infections amidst the onset of winter, it's not enough to rest all hope on quick access to a vaccine or improvements in COVID treatment. The virus still poses serious risks to those infected, and research into who is most susceptible to severe symptoms is as relevant as ever.

Earlier this year, researchers at Rutgers University launched a first-of-its-kind prospective study of 850 healthcare workers exposed to COVID-19, at least 10% of whom had already tested positive for the virus.

There is still much we don't know about why most people face mild symptoms while others become more severely ill. Led by Dr. Martin Blaser, the ongoing investigation is focused in particular on what gut health and the microbiome can tell us about COVID infection.

What the Study Is Investigating

Dr. Blaser, director of Rutgers University’s Center for Advanced Biotechnology and Medicine and professor of medicine and microbiology at Rutgers Robert Wood Johnson Medical School, is an expert on the human microbiome and its connection with diseases like asthma, diabetes, and cancer. When COVID hit the New York City metro area hard in the early spring, he quickly turned his attention there.

"There has been considerable literature (including our own work) that microbiome characteristics affect responses to invading pathogens, whether they are bacterial or viral," Blaser says.

If your unique microbiome impacts the severity of a COVID infection—or whether or not you contract the virus at all—this research may provide much-needed insight into those mechanisms.

Martin Blaser, MD

Knowing which microbiome predicts mild or severe [COVID] outcomes can thus lead to attempts to manipulate it to optimize outcomes.

— Martin Blaser, MD

With a wide range of outcomes among study participants, from no infection at all to more severe symptoms, this research could have broad implications, should the potential connection between COVID and the microbiome be identified.

As treatments continue to develop and vaccines are distributed to a wider population, researchers may even be able to determine more precisely how gut bacteria can be changed or supplemented to help prevent or treat infection. Early research into the effect of probiotics and prebiotics on COVID risk showed promising results.

"That's not surprising," Blaser says, "as one of the functions of the microbiome is to defend its host from invaders." He adds that an individual's particular microbiome characteristics may even predict the strength of their response to a vaccine.

The Emerging Field of Gut Health

The microbiome has only just begun to reach a broader audience, despite its impact on so many of the body's critical functions. From the kidneys, to the heart, and even the brain, proper gut health has effects that reach far beyond the digestive tract.

"The microbiome is newer in the scientific realm, and very complex," says Blaser, explaining why the immune-boosting benefits of good gut bacteria may be less well-known to the public than taking a daily multivitamin, for example.

Awareness is increasing, however, as evidenced by the rising popularity of probiotic supplements in recent years. Further research is needed, however, to confirm the substance behind the hype, given the evidence on both sides of the fence.

Martin Blaser, MD

There has been considerable literature that microbiome characteristics affect responses to invading pathogens, whether they are bacterial or viral.

— Martin Blaser, MD

While there is no disputing the importance of gut health, there is still much to learn about the potential to make proactive changes to our microbiome. The work of Blaser's team could help fill in some of those gaps, with implications for COVID and beyond.

Implications of the Study

As we continue to learn more about whos, whys, and hows of coronavirus infection, the fact remains that personal behavior and risk reduction strategies play the largest role in whether or not you become infected. Social distancing, wearing a mask, and washing your hands continue to be effective methods to stay safe.

That doesn't preclude other strategies, however. Now, as ever, exercise, sleep, mental wellness, and a healthy diet play important roles in maintaining a strong immune system that can help you fight infection.

Once the Rutgers study is concluded, Blaser hopes that "knowing which microbiome predicts mild or severe [COVID] outcomes can thus lead to attempts to manipulate it to optimize outcomes. These attempts can be in the form of probiotics or prebiotics, for example."

As a burgeoning area of research, there is still a lot to be learned through more studies like this one. "There is a growing field of pharmacomicrobiomics concerning the role of our microbiome in interacting with drugs," Blaser says, "In the future, doctors might want to assess a person’s microbiome in choosing between [drug] regimens."

Our current knowledge of the impact of the microbiome on overall health has only scratched the surface.

Where to Get Probiotics or Prebiotics

While many people choose to consume probiotics or prebiotics in supplement form, there are a number of common (and some less common) foods that contain them.

Probiotics can be found in fermented foods like yogurt, sauerkraut, and kimchi. Prebiotics, which are a type of fiber that feeds the good bacteria in your gut, can be found in a number. of everyday food items. The following foods, for example, are high in prebiotic fiber:

  • Legumes
  • Oats
  • Bananas
  • Berries
  • Asparagus
  • Garlic

Other Ways to Support Your Gut Health

In 2020, the average person has spent a lot of time (probably more than ever) making critical decisions about their health. While a global pandemic is not a path anyone would willingly choose, that increased awareness of the impact of our personal health choices will have lasting benefits.

When it comes to gut health, there are many things you can do beyond consuming probiotic foods. "Avoid anything that will suppress your current microbiome," Blaser says. "This includes unnecessary antibiotic regimens, antibacterials in many foods, even anti-bacterial soaps and toothpastes."

While it's important to be empowered in making personal health choices, Miguel Freitas, PhD stresses the importance of knowing what you're buying. "For instance, not all fermented or cultured foods and beverages contain probiotics." Freitas is the vice president of scientific affairs at Danone North America, a manufacturer of food brands like Oikos and Activia, which funded the Rutgers study.

What This Means For You

"Making sure you’re eating right, getting enough sleep, exercising regularly, and managing your stress can all positively improve your gut health," says Freitas. "More specifically, you can help support your gut health by consuming high-fiber foods, which can be beneficial to your digestive system and gut microbiome."

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