Gut-Immune Axis in Covid-19

How can you help to protect your body in the age of Covid-19?

What steps can you take beyond the recommended government measures?

What can we learn from peer-reviewed studies coming out of evidence-based medicine?

We believe these questions are crucial. At a time of uncertainty, we want to help people be proactive, preventative and personalised in their approach to health and wellness. We want to give people a greater sense of control.

So, where do we begin? One key system to look after is the gut and our digestive health.

Evidence shows the gut microbiota is central in how well we manage SARS-CoV-2 infection and the trajectory of Covid-19.

Let’s take a look at the what and the why.

Several papers now show a link between the diversity and balance of the gut microbiota and covid-19 outcomes.

For example, a recent analysis of 100 patients hospitalised with Covid-19 found a distinct pattern with the health of the gut microbiota and disease severity. Their conclusion was revealing:

Associations 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.

Another 2021 study investigated the link between disease severity and various biomarkers in 115 patients and found that gut microbiota diversity and C-Reactive Protein (CRP) were also predictors of disease severity in Covid-19. In fact, according to the authors, their model could predict 78.9% of people who went on to experience severe disease.

In particular, loss of commensal bacteria (“healthy gut bugs”) and an increase in opportunistic bacteria (“unwelcome gut bugs) was associated with disease severity. They summed up by saying:

we revealed for the first time an association between the gut microbiota and the WHO Clinical Progression Scale, which reflects patient trajectory during COVID-19. Our data showed that gut microbiota dysbiosis is present in moderate and severe COVID-19 patients in comparison to asymptomatic/mild patients.

So what are the links between the gut and the immune system in Covid-19?

"The health of our digestive system and the balance of microbes in the gut microbiota play a central role in our immune response and overall defence to Covid-19."

- Justin Buckthorp, MSc

Gut Dysbiosis & Covid-19 Cytokine Storm

The gut microbiota represents the trillions of microorganisms, including bacteria, archaea, fungi, and viruses, that live in the gastrointestinal tract.

These microbes constantly interface with the immune system and play a vital role in ensuring a balanced and effective immune response to external challenges, such as a virus.

It’s been estimated that up to 70% of immune-sensing cells reside in the gut. This shows you immediately the immediate and obvious link between gut health and immune function.

An imbalance in the gut microbiota is known as gut dysbiosis. This dysbiosis can be a result of “missing microbes” (lack of the good bacteria), an overgrowth of opportunistic bacteria (bad guys), or both.

Intestinal dysbiosis can impact our immune response to Covid-19 in various ways:

  • Gut dysbiosis can impact the healthy balance of bacteria in the lungs via the Gut-Lung Axis.
  • Gut dysbiosis can make the epithelial lining of the gut more permeable, which can provoke an increase in pro-inflammatory cytokines, such as TNF-a, Il-1b and Il-6.
  • Gut dysbiosis and a damaged epithelial lining in the gastrointestinal tract has been shown to the expression of ACE2, which enables SARS-CoV-2 to replicate further in the gut and spread to other parts of the body.

This list is not exhaustive and there are many ways in which connected systems in the body are negatively impacted by gut dysbiosis in the presence of SARS-CoV-2, and exacerbate the effect of Covid-19.

Thus, an imbalance in the gut microbiota can add to the cytokine burden and potentially play a role in triggering the “cytokine storm” which plays such a central role in the Covid-19 trajectory.

Starting Solutions

There is no one-size-fits-all approach to improving gut microbiota health because our microbiome is as unique as our fingerprints. Indeed, in over a decade of stool testing within our functional medicine work, we have never had a laboratory panel come back that is the same as someone else.

However, we can recommend some fundamental principles and quick wins, which can help you get on the right path towards improved microbiota health. From a dietary perspective, there are several avenues which can help:

  • Prebiotics
  • Probiotics
  • Gut-friendly foods

You can see the mechanisms by which these dietary components in the image below from a paper on the use of probiotics in Covid-19:

Focusing on the Gut

Prebiotics are classified as “a substrate that is selectively utilized by host microorganisms conferring a health benefit on the host”.

There are different types of prebiotics, but those containing GOS (Galactooligosaccharide) can help increase levels of Bifidobacterium and Lactobacillus, which play a central role in regulating inflammation and immune function.

Probiotics are defined as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host”.

Emerging research has shown the potential validity of probiotic therapy in Covid-19 infection, as part of wider medical care.

Gut-friendly food includes those foods that support gut microbiota diversity by increasing beneficial bacteria directly or via their preferred source of fuel; short-chain fatty acids (SCFA). Getting enough dietary fibre each day is crucial in increasing positive strains of bacteria. Certain foods are also excellent at increasing SCFA in the body, such as garlic, asparagus, artichoke, leeks and onions.

Whilst combining all three strategies at once will help synergistically, start where you are and embrace lifestyle change at a speed that works for you. If you need a quick win, take a probiotic and prebiotic daily. Success happens when habits are easy to do!

If you need further help, get in touch. We’d love to hear from you.

Justin Buckthorp, MSc

Justin Buckthorp is the Founder of 360. He has over 20 years of experience in health and wellness and is passionate about improving people's lives.

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