Although COVID-19 is primarily a respiratory disease, there is growing evidence that the gut microbiome is involved in this disease. Depending on which bacteria are present, the gut microbiome can improve or worsen the course of the disease. The influence of our gut also seems to make sense because it contains about 80% of our immune system.
The immune system is a defence system that encompasses many biological structures and processes within an organism and protects against disease. To function properly, an immune system must recognise a variety of pathogens and distinguish them from the organism’s own healthy tissue.
Often intestinal symptoms are the only symptoms
It is now known that the Corona virus not only affects the respiratory tract, but also other organs, such as the gut microbiome. Scientists from Canada analysed 36 studies and found that 18% of those affected suffered from digestive problems such as loss of appetite, nausea, vomiting, diarrhoea and abdominal pain. In 16% of corona patients, intestinal problems were the only symptoms.
Changes in the gut microbiome in severe cases of corona
It is already known that an overreaction of the immune system to the coronavirus influences the course of the disease. If the immune system acts too strongly against the pathogen, then stronger side effects and more frequent complications occur. As we already know, the gut microbiome plays an important role in regulating the immune system. Around 80% of immune cells are located in the gut. A healthy gut microbiome balances the immune system, prevents too strong defence reactions and at the same time has a positive effect on an immune system that is too weak.
Relationship between microbiome, severity and course of disease
Scientists at the Chinese University of Hong Kong have now been able to prove connections between a disturbed microbiome (dysbiosis), the severity and the course of a corona infection. For this purpose, stool samples from 87 infected patients were analysed, as well as from 13 people who were just recovering from the Corona infection. These were compared with 78 stool samples that had already been obtained from healthy individuals before the Corona pandemic. The analysis showed clear differences between infected and healthy people.
When the intestinal microbiome is out of balance (dysbiosis)
In the study, severe courses of disease were associated with a deficiency of certain bacteria. Faecalbacterium prausnitzii and Bifidobacterium bifidum were particularly deficient. Even after the infection had subsided, these bacteria were still present in insufficient numbers. At the same time, a correlation between a disturbance of the gut microbiome and the level of different inflammation parameters was found.
It is suspected that an imbalance of the gut microbiome (dysbiosis) could be responsible for the extent of the disease, as this can lead to a dysregulation of the immune system.
Further research is needed
There are still many unanswered questions in this area, but what is certain is that a gut microbiome that is out of balance is responsible for many ailments and affects our overall health and well-being. We recommend checking the gut microbiome regularly and consciously ensuring a strong gut microbiome and immune system through diet and lifestyle.
Lui, K., Wilson, M.P. & Low, G. Abdominal imaging findings in patients with SARS-CoV-2 infection: a scoping review. Abdom Radiol (2020)
Yun Kit Yeoh et al; Gut microbiota composition reflects disease severity and dysfunctional immune responses in patients with CORONA; Gut BMJ Journals (2021)