Covid-19 and the Gut Microbiome

With the Coronavirus pandemic taking the world by storm, it is now more important than ever to keep ourselves healthy and practise social distancing measures so as to not fall prey to the virus. Being a viral infection, medication alone cannot be used to treat it the way bacterial infections can. In other words, the body needs to rely on its own immune system. While modern medicine has allowed for the creation of the Covid-19 vaccine (I hope you're vaccinated by now!), it essentially serves as a function to assist your immune system in fending off the virus, but did you know, the trillions (that's more than 10^12) of tiny microorganisms living in your body also play an important role in supporting a healthy immune system?

Bacteria: Friend or Foe?

Maintaining a strong immune system is one of the key ways to keep viruses at bay, and it can be easily achieved by having a diverse range of bacteria present in your gut. However, not just any type of bacteria will do; these “good bacteria”, otherwise known as probiotics, are a special group of organisms that live inside our bodies to which we share a symbiotic relationship with. In exchange for their survival and growth, they confer on us a multitude of health benefits, most notably the fortification of our immune systems when present in the right amounts. Bacteria thrive and form a community inside our bodies known as a microbiome, and it is the diversity and size of this microbiome that our immune systems are fundamentally dependent on. Gut microbiomes essentially dictate our immune responses directly by regulating the activity of our immune cells, or indirectly by forming a physical barrier in our gut that is impervious to many types of bacteria and viruses, to name a few. Ultimately, more diverse microbiomes would mean that our bodies are better suited to respond to more types of bacterial and viral attacks.

Covid-19 patients were found to have less balanced gut microbiomes

In light of the ongoing pandemic, a recent study from the Chinese University of Hong Kong have shown that the gut microbiomes present in Covid-19 infected patients differed greatly from those in healthy individuals, regardless of whether they had been treated with medication such as antibiotics. The infected individuals were found to have much lower counts of certain species of gut bacteria that can significantly influence the immune system response, while also containing higher numbers of bacteria that are believed to be linked to certain autoimmune diseases. Those who have recovered from Covid-19 are not yet completely out of the woods, however, as some may become susceptible to certain post-Covid conditions such as Long Covid, an illness displaying covid-19-like symptoms and can last up to a few months after recovery, due to their weakened immune systems. While the cause-effect relationship between sickness and gut microbiome has yet to be confirmed, many ongoing studies all seem to agree that multiple pathologies (including Covid-19) are linked, in one way or another, to the unbalanced gut microbiomes of patients. It is evident that a healthy gut microbiome containing a wide range of probiotics is certainly beneficial in maintaining a stronger immune response, which can in turn reduce the chances of falling ill.

How do I obtain a more diverse microbiome?

The answer is simple (and delicious!): many fermented foods such as yoghurt, kimchi, and tempeh naturally contain probiotics due to the way they are produced. However, if your throat is parched and you want to drink something instead, then why not try some kombucha instead? But do remember that not all kombucha is created equal so look out for the ones that are raw, natural and unpasteurized, and ensure that they are not made from concentrates or contain any artificial sweeteners which actually turns the good bacteria in your gut bad. The many possible health benefits of kombucha may even serve to boost your immune system, so you can go about your daily activities and worry less about catching the flu. 

References

Badal, V. D., Vaccariello, E. D., Murray, E. R., Yu, K. E., Knight, R., Jeste, D. V., & Nguyen, T. T. (2020). The Gut Microbiome, Aging, and Longevity: A Systematic Review. Nutrients, 12(12), 3759.

Clem, A. S. (2011). Fundamentals of vaccine immunology. Journal of global infectious diseases, 3(1), 73.

La Fata, G., Weber, P., & Mohajeri, M. H. (2018). Probiotics and the gut immune system: indirect regulation. Probiotics and antimicrobial proteins, 10(1), 11-21.

Yeoh, Y. K., Zuo, T., Lui, G. C. Y., Zhang, F., Liu, Q., Li, A. Y., ... & Ng, S. C. (2021). Gut microbiota composition reflects disease severity and dysfunctional immune responses in patients with COVID-19. Gut, 70(4), 698-706.

Long Covid information retrieved from: https://www.cdc.gov/coronavirus/2019-ncov/long-term-effects.html

Fermented foods information retrieved from: https://www.health.harvard.edu/staying-healthy/how-to-get-more-probiotics