Inside your body, there is an army of microbes working overtime to protect your health. Part of their protective work is to do with regulating the immune system. And that matters when it comes to fighting runaway viral infections and avoiding long-term side effects: We’re talking about long Covid.
In a study published earlier this year in the aptly titled journal, Gut, scientists lay out evidence showing the bacteria in your gut may influence your risk of developing long Covid. The reason why comes back to your gut microbiome’s fundamental role in regulating the immune system, according to the study. The term ‘long Covid’ is associated with numerous long-term side effects associated with a coronavirus infection — after the infection clears, some people are left with an array of lingering issues, including “brain fog,” forgetfulness, physical weakness, and more.
The discovery — People with and without Covid-19 have clear differences in the composition of their gut microbiome, according to the study. The study involved a small sample of 100 people, so the results need to be taken with a pinch of salt until replicated by larger studies.
In particular, three species of gut bacteria — Faecalibacterium prausnitzii, Eubacterium rectale, and bifidobacteria — stood out in the analysis. Patients with the severest disease also had lower levels of these three microbes in their gut microbiomes, and their gut microbiomes remained altered for at least 30 days after the infection had cleared.
The findings suggest an altered gut microbiome may help predict whether a person will fully recover from Covid-19 infection or become a long-hauler.
“Fruits, yogurt, and fiber-containing foods would be practical means to develop a healthy gut microbiome.”
Digging into the details — The microbial imbalance seen in patients with long-term symptoms was associated with high cytokine levels and other blood markers of tissue damage, such as C-reactive protein and other enzymes. The immune system releases these proteins to fight Covid-19, but prolonged infection can result in an overproduction of cytokines known as “cytokine storms,” which damage nearby tissue and organs. This over-aggressive immune response is in turn linked to the long-term features collectively known as long Covid.
“Imbalanced gut microbiota or ‘dysbiosis’ weakens our immune defense, thereby predisposing to more severe SARS-CoV-2 infection and potentially contributing to ‘long Covid,’” study co-author Siew C Ng previously told Inverse. Ng is a professor of Medicine and Therapeutics at The Chinese University of Hong Kong.
Why it matters — Scientists now think one in three people who are infected with the coronavirus will go on to develop long Covid.
What we do know is that long Covid is debilitating. It can prevent people from resuming daily activities like returning to work. As of July 2021, the United States government decided to categorize long COVID as a disability under the Americans with Disabilities Act.
What we don’t know is just how long long Covid can last, however, preliminary research suggests some people may experience symptoms five months after they no longer test positive for Covid-19.
We also don’t know what causes long Covid or why there is such variety in the symptoms long haulers experience — which makes it hard to treat. To add to the confusion, there’s no clear timeline as to how long it takes to recover from long Covid.
With so many unknowns, prevention may be a viable treatment strategy in itself. Good gut health helps manage other inflammatory diseases, and this study shows gut microbes may also play a role in tamping down high inflammation caused by Covid-19.
“Maintaining a healthy microbiome through healthy diet would definitely benefit in fighting against Covid-19,” Hasan Zaki, an assistant professor at UT Southwestern who was not involved in this study, previously told Inverse.
“Avoiding high fat and high sugar diets, and taking fruits, yogurt, and fiber-containing foods would be practical means to develop a healthy gut microbiome.”