Understanding Long COVID and Its Impact on Gut Health

The Lingering Threat: Long-Term Effects of COVID-19 on Gut Health

2020 was a challenging year. The emergence of the COVID-19 virus introduced a profound menace to public health. As of this writing, over 770 million people worldwide have been infected with COVID-19, and over 6.95 million deaths have been attributed to the disease. The deaths from COVID-19 infections are bad enough, but survivors of the infection commonly experience persistent symptoms that interfere with their quality of life. At least 65 million people worldwide are estimated to have long COVID, with a projected incidence of at least ~10% in infected patients. 

Long COVID’s Multisystemic Impact

Long COVID is a multisystemic phenomenon, presenting in a variety of ways and affecting various organs, including the heart (chest pain, palpitations), brain (cognitive impairment, sleep disorders, fatigue), lungs (cough, shortness of breath), sexual organs (erectile dysfunction, irregular menstruation). Of particular interest to the Foodguides.com audience – long COVID is also linked to gut dysfunction.

The Gut-Brain Axis and Long COVID

Long COVID-19 can produce a multitude of symptoms that disrupt gut function. These symptoms are reported in as many as 29% of individuals coping with long COVID. These symptoms include loss of appetite, nausea, weight loss, abdominal pain, heartburn, dysphagia, altered bowel motility, and irritable bowel syndrome. How does the virus cause these persistent gut problems?

Mechanisms Behind Gut Disruption in Long COVID

Dysbiosis- the effects of the virus itself and your immune response to the virus potentially alter the composition of bacteria in your gut microbiome. We have published several excellent articles about the importance of the gut microbiome and keeping it in balance; here is a good one on what exactly gut dysbiosis is. 

Persistent cellular abnormalities in blood and mucosa- your gut, in addition to its role in digestion, is an important compartment of your immune system. The virus itself, or your immune response to it, can damage the delicate cells and the lining of your intestines, resulting in a lasting increase in intestinal permeability. This is not a good thing! Learn more about intestinal permeability here. 

Altered neuro-immune interaction- The disruption of the gut microbiome and the leaky gut can lead to a situation in which your immune system is being chronically activated. In this state, chemicals released by your immune cells, called cytokines, can build up in your bloodstream and lead to widespread effects throughout your body. This is likely the explanation for why COVID-19's long-term effects can be so extensive. Furthermore, nerves that directly innervate the gut are stimulated by inflammation, leading to cross-talk between the gut and brain. 

Coping with Long COVID

What is the prognosis for patients experiencing long COVID? Here is where things are a bit depressing (as if anything COVID-related isn’t unfortunate enough). Current research is just beginning to understand the mechanisms leading to long COVID. As a recently published review paper states, diagnostic and treatment options for patients are currently insufficient. 

Rapid advances in science and medicine can change this very soon. The best strategy one can use is to keep current with vaccinations (long COVID rates are lowest among the vaccinated) and practice social-distancing measures to reduce exposure odds. Unfortunately, the COVID-19 epidemic is still with us.    

1. _{Blackett, J. W., Wainberg, M., Elkind, M. S. V., & Freedberg, D. E. (2022). Potential Long Coronavirus Disease 2019 Gastrointestinal Symptoms 6 Months After Coronavirus Infection Are Associated With Mental Health Symptoms. Gastroenterology, 162(2), 648–650.e2.}
2. _{Davis, H. E., McCorkell, L., Vogel, J. M., & Topol, E. J. (2023). Long COVID: major findings, mechanisms and recommendations. Nature reviews. Microbiology, 21(3), 133–146.}
3. _{Lai, N. Y., Musser, M. A., Pinho-Ribeiro, F. A., Baral, P., Jacobson, A., Ma, P., Potts, D. E., Chen, Z., Paik, D., Soualhi, S., Yan, Y., Misra, A., Goldstein, K., Lagomarsino, V. N., Nordstrom, A., Sivanathan, K. N., Wallrapp, A., Kuchroo, V. K., Nowarski, R., Starnbach, M. N., … Chiu, I. M. (2020). Gut-Innervating Nociceptor Neurons Regulate Peyer's Patch Microfold Cells and SFB Levels to Mediate Salmonella Host Defense. Cell, 180(1), 33–49.e22.}
4. _{Meringer, H., & Mehandru, S. (2022). Gastrointestinal post-acute COVID-19 syndrome. Nature reviews. Gastroenterology & hepatology, 19(6), 345–346.}
5. _{World Health Organization. (n.d.). Covid-19 cases | WHO COVID-19 Dashboard. World Health Organization.}