Why did Covid affect some people more severely? The answer may lie in your gut.
If the past three years have taught us anything, it’s that our immune system plays an important–perhaps the most important role, in our overall health. While many individuals emerged unscathed from the pandemic, many others unfortunately did not survive or suffered severe illness from Covid. What was the cause of this discrepancy and what was protecting children from more severe infection? My colleagues and I believe it lies in the gut. While I am not an immunologist, nor a researcher, my background as an Internal Medicine physician specializing in integrative medical weight loss coupled with my long term fascination with the gut was what sparked the interest that led to our hypothesis.
The Cytokine Storm
A little background on our study, which was the first to link Covid-19 severity to gut health.
When the pandemic first arrived in the US, New York was one of its first landing spots. As with many other medical offices, my wellness and medical weight loss practice was deemed “non-essential” and closed. My husband, a Pulmonologist/Intensivist experienced the opposite effect and he and his colleagues were thrust onto the frontlines, seeing Covid-infected patients in the ICU early on. He noticed that although many of his sick patients in the intensive care unit were either elderly or with comorbid conditions, many others were younger and did not have any medical conditions other than being overweight with a BMI over 25. We had nightly conversations about what he was seeing and then one night, the lightbulb went off. What was causing a lot of patients to get sick was not what the virus was doing directly, but how the body’s immune system responded to the virus. Those getting severely ill were developing a condition called the “Cytokine Storm” and they had markedly elevated inflammatory markers in their bloodstream. One of the medications used early on for treatment focused on inhibiting one particular inflammatory marker called Interleukin 6 (IL-6). To understand the role of inflammatory markers in the deadly “Cytokine Storm”, we must first understand a little bit about how our immune system responds to infections.
Think of your immune system as a security guard for your body—always on the lookout for any intrusions or infections. While the immune system is complex, its ultimate goal is to protect us from anything it perceives as an intrusion. Cytokines act as messengers for our immune system. A smaller subset of cytokines called interleukins are also released in response to a perceived intruder in the body such as a viral infection. There are several different types of these mini messengers (interleukins) and the role of each varies.
When someone is infected with a virus such as COVID-19, the immune system reacts with release of these initial responders in an effort to control the inflammatory problem caused by the virus. [Source] In some individuals however, the response is more profound than in others and triggers a “Cytokine Storm.” The problem with the Cytokine Storm is that it attracts even more immune cells to fight the infection, causing a more exacerbated systemic inflammation and further damage to tissues.
One of the main proinflammatory culprits involved in the Cytokine Storm is Interleukin-6 (IL-6). Interleukin-6 is meant to be released in short bursts to localize and control inflammation. Unfortunately, some individuals had persistently elevated levels of IL-6 prior to becoming infected with Covid. The prolonged or chronic presence of this proinflammatory marker is not good for the body and signals a chronic inflammatory state. Individuals with higher than normal levels of IL-6 at baseline are the same patients that were developing the deadly Cytokine Storm and getting more severely ill from Covid-19. Patients with conditions such as diabetes and heart disease are known to be at increased risk, but why are those with elevated body mass indexes also getting severely ill, and why are the majority of children not? The answer lies in the gut microbiome.
The Role of the Gut
The Gut microbiome of all individuals varies greatly. Children’s guts are overall much healthier than adults and have a higher concentration of certain gut bacteria (microbes) than adults do. Our gut microbes work together with our immune system—a large portion of which is already present in the gut. Children have a much higher concentration of a specific gut bacteria called Bifidobacterium. Bifidobacterium accounts for up to 60-80% of their gut microbiome. The levels start to decrease as we get older and are especially low in those with the same high risk conditions causing severe covid related infections (See figure below). In our research study, we found that children seem to be protected from more severe Covid infections because Bifidobacterium functions as an immune regulator and down regulates IL-6—the same pro-inflammatory cytokine that causes havoc in Covid severity and the deadly Cytokine Storm.
Additional Studies linking the gut to Covid
There was much speculation initially and as hard as we tried to share this information, it didn’t get much traction. Probiotic rich foods or supplemental probiotic formulation have never killed anyone and in fact could have potentially saved many lives. However, since our study was first published, several additional studies have been published that confirm our theory and show a connection between gut health and Covid. In a January 2021 a study out of Hong Kong University, stool samples of patients hospitalized with Covid showed deficiencies of certain bacteria including Bifidobacterium.
Fast forward 3 years and there are now at least ten additional studies showing the link between the deficiency of bifidobacterium and covid severity. One study even demonstrated that Ivermectin’s mechanism of action is to also downregulate Il-6 and that it does this by increasing bifidobacterium levels! Microbiome-Based Hypothesis on Ivermectin’s Mechanism in COVID-19: Ivermectin Feeds Bifidobacteria to Boost Immunity
Some studies Published in Italy and Israel also showed that probiotic administration and foods high in live bacteria such as yogurt and kefir, improved the outcome of Covid-19 in infected patients. An online group of critical care doctors called The National Critical Care Alliance has also added probiotics containing the bifidobacterium strain as part of their first line treatment protocol for patients hospitalized with CoViD.
So….What Can you do to improve your gut health?
1- Start by eating the rainbow. Plant based foods such as fruits,vegetables and legumes are rich in prebiotic fibers that help good gut microbes such as Bifidobacteria thrive in our gut.
3- Consider taking a probiotic. Your probiotic should contain Bifidobacterium and Lactobacillus. It is best to take your probiotics on an empty stomach.
Banner Image: Covid-19 virus. Image Credit – CDC