For decades, scientists have been studying the role the human microbiome plays on health. The gastrointestinal tract, or simply the “gut,” is made up of a series of organs essential for breaking down food, absorbing nutrients, and excreting waste. But it also harbors a vibrant, complex community of trillions of bacteria, fungi, and other microbes that together make up the gut microbiome.

In addition to controlling digestion, the gut microbiome is in constant close communication with the immune system. In fact, research shows that a big portion of the body’s immune cells actually lives in the gut.

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An imbalance of gut bacteria, known as dysbiosis, has been identified as a risk factor for several diseases, including irritable bowel syndrome (IBS), heart disease, diabetes, as well as certain neurological conditions like late-onset dementia and Parkinson’s disease. Now, a new review suggests that certain alterations in the gut may influence both the short and long-term effects of COVID-19 infection.

The study

In a review published this month in mBio, Dr. Stanley Kim, a microbiologist from Korea University, examined emerging evidence regarding how an altered gut microbiome may contribute to severe COVID-19. In his analysis, Kim noted that some medical conditions associated with severe illness from COVID-19, including obesity, diabetes, and high blood pressure, have been linked to poor gut health. Advanced age, another risk factor for severe COVID-19, is also closely related to a weakened gut microbiome.

When the gut is in dysbiosis, Kim said, it may be easier for SARS-CoV-2 – the virus that causes COVID-19 – to penetrate the barrier that protects the gut and other internal organs. When this barrier is compromised, pathogens like viruses or harmful bacteria may gain access to the intestinal lining and cause inflammation and internal damage.

There is not enough evidence yet to draw a connection between COVID-19 and the gut microbiome. However, recent studies looking at stool samples have noted a reduced bacterial diversity in COVID-19 patients. Scientists still have a lot to learn about how gut bacteria influence COVID-19 progression and outcomes. Nevertheless, strengthening the gut may help protect the digestive tract against the virus’s potential effects and improve overall health.

Here are five easy, research-backed tips to improve gut health:

  • Eat more fiber: Kim recommends consuming 25-30 grams of dietary fiber every day. Fiber-rich foods like psyllium, lentils, beans, peas, and broccoli can help build good gut bacteria.
  • Take a probiotic: Probiotics have been associated with numerous health benefits, including improved digestion, better absorption of nutrients, and a more robust immune system. Probiotics promote the growth of beneficial bacteria in the gut.
  • Get more sleep: The relationship between sleep and the gut is a two-way street. A healthy gut microbiome promotes sleep, and sleep seems to affect bacterial diversity in the gut.
  • Eat fermented foods: Fermented foods are naturally probiotic. People who eat fermented foods regularly tend to have a more diverse microbiome.
  • Limit sugar and artificial sweeteners: Research shows that artificial sweeteners negatively impact gut health. A diet high in processed foods and added sugars has also been linked to a decreased amount of good bacteria in the gut.