COVID and your gut: How a healthy microbiome can reduce the severity of infection—and vice versa

A vast combination of microorganisms live in our gut, including bacteria, fungi and viruses. Collectively, we refer to this as thethe microbiome.

Despite their tiny size, these microbes have significant effects on our health and well-being. In fact, the microbiome is often referred to as the "second brain" due to the extensive relationship it has with the body's organs and systems.

One role in particular the microbes in our gut play is supportingimmune function. They help to control local and systemic inflammation, the process by which the immune system protects us from harmful pathogens.

So it's not entirely surprising thatresearch has shownthe make-up ofbacteriain the gut may influence the severity of a COVIDinfection. At the same time, evidence is beginning to suggest a COVID infection couldaffect the balanceof bacteria in the gut, which might go some way to explaining why some people have persistent symptoms after a COVID infection.

The microbes in our gut provide essential signals for our immune responses across the body, including in the lungs. A "healthy" gut microbiome comprises a broad range of bacteria, though is not identical in every person. Studies have previously shown that ahealthy gut microbiomecan improve the immune response to respiratory infections by regulating immune cells and messages.

On the flip side, evidence shows a poorer composition of gut bacteria increases susceptibility toinfluenza infections in the lungs, and leads to reducedclearance of germsfrom the lungs in mice.

With COVID, it similarly appears that the make-up of the gut microbiome can influence the course of disease. Research has shownan associationbetween the microbiome profile and levels of inflammatory markers in patients with COVID, where patients with a poorer combination of gut bacteria show signs of too much inflammation. This suggests the microbiome influences the severity of a COVID infection via effects on the immune response.

Unbalancing the microbiome

Just as the composition of our gut bacteria appears to influence how we fare with COVID, the reverse might also be true—a COVID infection could affect the make up of our gut bacteria. Specifically, it seems COVID might throw off the balance between "good" and "bad" microbes in a person's microbiome.

Studies have shown a significant difference in the gut microbiome betweenCOVID patientsand healthy people. We see a reduction inbacterial diversityin the gut in COVID patients—so a smaller range of species, as well as substantial differences in the species of bacteria present.

Notably, scientists have observed a reduction in a group known ascommensal bacteriain COVID patients, which act on the immune system to help prevent invasion by pathogens. This may increase our risk of other infections after COVID. Simultaneously, there appears to be an increase in a variety of opportunistic pathogenic bacteria that are known to cause infections.

This "imbalance" is called dysbiosis, and these changes have been shown to still be present in patients30 days post-infection.

Recent studies have suggested gut dysbiosis is linked to the movement of gut bacteriainto the blood在COVID感染。在老鼠身上,COVID ch引起的anges in a variety of parameters associated with gut barrier permeability, meaning things can theoretically move more easily through the gut wall.

In 20% of human COVID patients in this same study, certain bacteria from the gut had migrated into the bloodstream. This group was at higher risk of developing a secondary infection in the blood.

Research is now also showing that dysbiosis following COVID may contribute tolong COVID, with gut dysbiosis more prevalent in patients presenting withlong-term COVID symptoms. This makes sense because dysbiosis seems to put the body in a heightened and constant stateof inflammation—something that's associated with chronic COVID symptoms.

Supporting your immunity

As we continue to develop a more comprehensive understanding of gut microbes and their role in inflammation, how can you help keep your immune system healthy to protect yourself against COVID and other infections?

Certain nutrients,includingvitamins A, C, D and E as well as iron, zinc and omega-3 fatty acids, all have positive effects on immune responses against viral infection.

AMediterranean diet, which is rich in vitamins, minerals and dietary fiber, has an anti-inflammatory effect in the gut. Interestingly, a strain of bacteria known as Faecalibacterium prausnitziiis key to immune regulation. It's frequently low in the western diet, but abundant in the Mediterranean diet.

Ideally you should avoid too many refined cereals, sugars and animal fats, which can allheighten inflammationin the body.

Probiotics, supplementary blends of live bacteria, may also have benefits. A blend of bacterial strains Lactiplantibacillus plantarum and Pediococcus acidilacticiwas shown to reducethe quantity of virus detected in the nasal passage and lungs, as well as the duration of symptoms in COVID patients.

This combination also significantly increased theproduction of COVID-specific antibodies, suggesting probiotics act directly by interacting with the immune system, rather than solely changing the composition of the gutmicrobiome.

Finally, moderateexercisecan also help support theimmune systemto fight COVID.

This article is republished fromThe Conversationunder a Creative Commons license. Read theoriginal article.