Gut health and COVID-19 |

Gut health and COVID-19

By Pauli Halstead and Joy Brann


Hippocrates had it right 2,000 years ago: “All disease begins in the gut.”

Although COVID-19 is primarily a respiratory illness, mounting evidence suggests that an unbalanced gut microbiome may impact disease severity for some people.

The gut is the largest immunological organ in the body. About half of our antibodies are made in the gut lining. Immune cells require a healthy gut microbiota for their production and function, whereas the lack of microbial diversity impairs metabolic function and immune response.

Your gut houses a diverse microbiome of around 100 trillion microorganisms. A healthy balanced gut flora helps with digestive function, protection against infections, healthy and stable metabolism, and a well-functioning immune system. When the gut microbiome is compromised, chronic illnesses may also co-occur. Factors that can disrupt the gut microbiome and cause proliferation of pathogenic bacteria include common medications and antibiotics, stress, refined carbohydrates, industrial seed oils and herbicides used in agriculture.

The health of your gut is directly connected to countless other systems throughout your body. Imbalance in the microbiome and poor gut integrity are associated with chronic health problems, including obesity, diabetes, depression, impaired brain function and more.

The gut-brain axis (GBA) consists of bidirectional communication between the central and the enteric nervous system, linking emotional and cognitive centers of the brain with peripheral intestinal functions. This two-way interaction between microbiota and GBA occurs through signaling via neural, endocrine, immune, and antibody-mediated pathways.

COVID-19 infection prompts the immune system to produce an inflammatory cytokine response. Analysis of blood samples shows that disruption of microbial balance found in COVID patients also correlates with a pro-inflammatory gut microbiome, raised levels of inflammatory cytokines and blood markers of tissue damage, such as C-reactive protein and certain enzymes. This suggests that the gut microbiome might influence the immune response to COVID-19 infection and potentially affect disease severity and recovery.

There is a subset of recovered patients with COVID-19 who experience persistent symptoms such as fatigue, breathlessness, joint pains, depression and hair loss for months after the initial onset of symptoms. Increasing evidence suggests that gut dysbiosis could be contributing to immune-related health problems post COVID illness.

Observational studies point to mounting evidence that pathogenic bacteria contribute to inflammatory diseases both in the gut and elsewhere in the body. Increasing beneficial gut bacteria species found to be deficient during COVID illness may help reduce severity of disease. Therefore, managing patients’ gut microbiota could be an important adjunct to recovery during and after illness, and in preventing infection.

What can a person do to improve their gut health and immune system? Again, attributed to Hippocrates, “Let food be thy medicine, and let medicine be thy food.”

What’s the best way of improving gut flora?

Food First: The Standard American Diet (SAD) is riddled with refined sugars, processed foods and so many things that damage the gut microbiome. First focus on nutrition; then complement that with supplements like digestive enzymes and pre-or-probiotics, as well as other supports for the gut microbiome. Prebiotics include cruciferous vegetables (e.g., broccoli, brussels sprouts, kale, cauliflower, bok choy), resistant starches like a slightly unripe banana, and berries. -Robin Rose, M.D., Board-Certified Specialist in Gastroenterology and Internal Medicine.

Improve dietary choices by reducing consumption of processed foods and increasing your intake of organic foods. A palate addicted to processed foods, junk food snacks and fast foods may respond better by introducing healthy alternatives gradually. For example, try switching from pesticide laden corn or canola oil to organic olive oil, ghee, avocado or coconut oil. Gradually introduce healthy substitutions, such as fresh and dried fruits and nuts instead of processed snack foods.

It is especially important to avoid foods sprayed with the herbicide glyphosate, as any minuscule amount kills beneficial gut bacteria. In 2019, the Environmental Working Group ( reported widespread glyphosate contamination in many cereal grains, wheat products and legumes. More than 40 countries throughout the world have imposed bans and restrictions on the use of glyphosate.

Foods found to be highly contaminated with glyphosate are sugar, oats, wheat, barley and legumes (lentils, chickpeas, soy and other beans). Prioritize choosing organic when purchasing these foods. The EWG offers dirty dozen lists of toxic foods and products to avoid.

Health experts specializing in nutrition, colon health and gastroenterology can offer individualized support for improving diet and gut health. Learn more from Chris Kresser, M.S., L.Ac., about how specific diets can help reduce inflammation and address chronic conditions.

Article sources can be found in The Union’s online version.

Pauli Halstead is the author of “Primal Cuisine: Cooking for the Paleo Diet” and Joy Brann, MPH, works in health education and policy


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