Physician Outlook

The Gut Microbiome: A Defense Against COVID-19

The Gut Microbiome: Research examines the link between gut flora and health.

Over the last few years, I've often seen articles and publications that refer to the gut as the "second brain" and with the mound of evidence that keeps rolling in, it’s easy to see why researchers and wellness experts alike not only agree with this statement but continue to study this connection to fully understand how these two systems communicate. Well over 2000 years ago Hippocrates said that all disease starts in the gut and while it may not be a scientific fact that ALL disease starts in the gut, it’s likely that many diseases and conditions show a similar pattern of disruption in the gut. We can now see how the delicate ecosystem that encompasses our digestive system can certainly impact immunity, brain function, inflammation and metabolism and play an important role in wellness and disease. This is an important consideration and timely today as a strong immune system can help us battle COVID-19.



By now you’re probably familiar with the terms “gut microbiome”, “gut flora”, or “microbiota”. These terms can be used somewhat interchangeably to represent the entire digestive tract which extends from mouth to anus and is made up of everything in between including the esophagus, stomach, large and small intestine, liver, pancreas, gallbladder.


This system I like to call the gut microbiome is a diverse collection of microbes that consist of bacteria, viruses, fungi and genes and have many important biological functions. It is estimated that between 300-500 different species of bacteria alone contribute upwards of 10–100 trillion cells that are housed in the gut and much like a fingerprint, is unique to all of us and can change over time to become stronger and more diverse but it can also become compromised. Some of the factors that influence the makeup of our gut environment include diet, lifestyle, and genetics. It is also believed that your mother’s gut health can influence the diversity and health of the microbiome in early life while diet and lifestyle become better indicators as we age.


Research suggests that changes in the diversity of gut microbes can greatly impact health. We often see certain strains of bacteria in people who are healthy and other common patterns and microbes in people with disease. For optimal health, a diverse ecosystem will keep us strong, healthy and resilient.


How Gut Health Can Impact Wellness



Our intestinal lining is meant to be a shield that protects foreign and harmful invaders from entering. One advantage of having a diverse and healthy microbiome is the gut lining will remain strong and intact and beneficial bacteria and other microbes will keep pathogens and other harmful bacteria from being able to colonize by crowding them out. This is one of the ways we can protect our immune system, as a large majority of immune cells reside in the gut. During a pathogenic infection, gut microbiota promotes the production of an antibody that protects against infection called IgA that binds to the invading microbes to neutralize and get rid of them. Improving gut function is one way we can improve our immune defenses and help protect us from something like COVID-19.



The microbiome can influence metabolism and impact metabolic disease in several ways. It plays a role in nutrient absorption, particularly B Vitamins and Vitamin K, and can also influence lipid metabolism and insulin homeostasis. Our gut also plays a role in hormone production and assists in the conversion of thyroid hormone T4 into the more active version T3 but when the integrity is compromised in any way these chemical reactions cannot take place effectively. This can also compromise the integrity of the intestinal wall causing a condition known as “leaky gut” where undigested food particles can get out and potentially dangerous pathogens can enter. Chronic stress, certain foods, medications and other lifestyle factors can lead to chronic conditions and diseases associated with metabolism.


Brain Function

The gut/ brain connection has been well established and serves as a scientific area of study that few would dispute yet few truly understand. Many of the signals sent by the brain in order to perform the millions of chemical reactions that need to take place are sent to the gut. For example, certain species of bacteria can help produce neurotransmitters like serotonin that's mostly made in the gut.



The body creates inflammation to protect itself from infections, injuries, and other harmful substances. Some inflammation is healthy and good but prolonged, chronic inflammation is not. In fact, chronic inflammation plays a role in diseases like Crohn’s, MS, RA, IBS, Leaky Gut, and diabetes just to name a few. Some foods, drugs, environmental toxins, stress, and lifestyle can also contribute to chronic inflammation which can lower our immunity, compromise our gut function and leave us vulnerable to things like the coronavirus. In the coming months we will discuss the potential of targeting the microbiome therapeutically to promote health and to prevent or treat medical conditions.


Final Thoughts

Seems a logical conclusion that we should not ignore gut health and its role in several biological processes throughout the body. Some food for thought to improve gut function may include diet and lifestyle changes like a diverse and healthy diet that includes plenty of fiber and eliminates sugar and artificial sweeteners.  Exercise and move, and try adding probiotics, digestive enzymes, and fermented foods.



Campbell AW. Autoimmunity and the gut. Autoimmune Dis. 2014; 2014:152428. doi:10.1155/2014/152428

Durack J, Lynch SV. The gut microbiome: Relationships with disease and opportunities for therapy. J Exp Med. 2019;216(1):20–40. doi:10.1084/jem.20180448

Mukherjee S, Joardar N, Sengupta S, Sinha Babu SP. Gut microbes as future therapeutics in treating inflammatory and infectious diseases: Lessons from recent findings. J Nutr Biochem. 2018; 61:111–128. doi: 10.1016/j.jnutbio.2018.07.010

Ursell LK, Metcalf JL, Parfrey LW, Knight R. Defining the human microbiome. Nutr Rev. 2012;70 Suppl 1(Suppl 1): S38–S44. doi:10.1111/j.1753-4887.2012. 00493.x

Leave a comment

You need to Login or Register