Wow, who even thought we would be subject to a pandemic in the first place! The multitude of effects, be it health in a physical and mental space or the numerous economic implications, have touched on all our lives. So, let’s talk about the link between the severity of COVID-19 symptoms and gut health!

Immunity and Gut Health – COVID-19 findings:

Poor gut health linked to the severity of symptoms experienced with COVID-19.

People infected with COVID-19 experience a wide range of symptoms and severities, the most common including high fevers and respiratory problems. However, autopsy and other studies have also revealed that the infection can affect the liver, kidney, heart, spleen, and even the gastrointestinal tract. A sizeable fraction of patients hospitalized with breathing problems also experienced gastrointestinal disorders such as diarrhea, nausea and vomiting. This suggests that when the virus and the GI tract become involved, it increases the severity of the disease and associated symptoms.

In a review published this week in mBio, an open-access journal of the American Society for Microbiology, microbiologist Heenam Stanley Kim, Ph.D, from Korea University’s Laboratory for Human-Microbial Interactions, in Seoul, examined emerging evidence suggesting that poor gut health adversely affects COVID-19 prognosis. Based on his analysis, Kim proposed that gut dysfunction may worsen the severity of infection by enabling the virus to access the surface of the digestive tract and internal organs. These organs are vulnerable to infection because they have widespread ACE2—a protein target of SARS-CoV-2—on the surface.  

“There seems to be a clear connection between the altered gut microbiome and severe COVID-19,” Kim said. 

Studies have demonstrated that people with underlying medical conditions including high blood pressure, diabetes and obesity have a higher risk of severe COVID-19. Risk factors increases with age, with the older population demographic most vulnerable to serious complications and increased chances of hospitalization. But both advanced age and chronic conditions, have a well-known association with an altered gut microbiota and poor gut health. This imbalance can affect gut barrier integrity, Kim noted, which can allow pathogens and pathobionts easier access to cells in the intestinal lining. 

So far, the link between gut health and COVID-19 prognosis hasn’t been empirically demonstrated, Kim noted. Some researchers have argued, he said, that unhealthy gut microbiomes may be an underlying reason for why some people have such severe infections. 

The problem with gut health goes beyond COVID-19, though, he said. Once the pandemic passes, the world will still have to reckon with chronic diseases and other problems associated with poor gut health. 

“The whole world is suffering from this COVID-19 pandemic,” Kim said, “but what people do not realize is that the pandemic of damaged gut microbiomes is far more serious now.” 

In a separate two-hospital cohort study, blood, stool and patient records from 100 patients with laboratory-confirmed SARS-CoV-2 infection were obtained. Serial stool samples were collected from 27 of the 100 patients up to 30 days after clearance of SARS-CoV-2. Gut microbiome compositions were characterised by shotgun sequencing total DNA extracted from stools. Concentrations of inflammatory cytokines and blood markers were measured from plasma.

It was found that an association between gut microbiota composition, levels of cytokines and inflammatory markers in patients with COVID-19 suggest that the gut microbiome is involved in the magnitude of COVID-19 severity possibly via modulating host immune responses. Furthermore, the gut microbiota dysbiosis after disease resolution could contribute to persistent symptoms, highlighting a need to understand how gut microorganisms are involved in inflammation and COVID-19.

References:

Poor Gut Health Connected to Severe COVID-19, New Review Shows Jan. 12, 2021, American Society for Microbiology .

Gut microbiota composition reflects disease severity and dysfunctional immune responses in patients with COVID-19

http://orcid.org/0000-0003-0241-6117Yun Kit Yeoh1,2, 

http://orcid.org/0000-0001-8450-5281Tao Zuo2,3,4, 

Grace Chung-Yan Lui3,5, Fen Zhang2,3,4, Qin Liu2,3,4, Amy YL Li3, 

Arthur CK Chung2,3,4, Chun Pan Cheung2,3,4, Eugene YK Tso6, Kitty SC Fung7, Veronica Chan6, Lowell Ling8, Gavin Joynt8, David Shu-Cheong Hui3,5, http://orcid.org/0000-0001-5310-5197Kai Ming Chow3, Susanna So Shan Ng3,5, Timothy Chun-Man Li3,5, Rita WY Ng1, Terry CF Yip3,4, 

http://orcid.org/0000-0002-2863-9389Grace Lai-Hung Wong3,4, 

http://orcid.org/0000-0001-7388-2436Francis KL Chan2,3,4, 

Chun Kwok Wong9, Paul KS Chan1,2,10, 

http://orcid.org/0000-0002-6850-4454Siew C Ng2,3,4