Effects of Diet in COVID-19?
Diets high in fiber could play a role in COVID-19 infections as it increases the production of short-chain fatty acids in the intestines, which are essential for immune defense. On the other hand, the intestinal flora changes with a SARS-CoV-2 infection, which also leads to a lower release of short-chain fatty acids in the intestine. A current study has now examined the connections between short-chain fatty acids and COVID-19.
The researchers from the University of Campinas analyzed how changes in the short-chain fatty acids influence infections with SARS-CoV-2. The result of the study was published in the English-language journal “Gut Microbes” released.
Gastrointestinal Symptoms of COVID-19
Up to 50 percent of people with COVID-19 experience gastrointestinal symptoms such as diarrhea, vomiting, and abdominal pain. Such symptoms are found in 17.6 percent of severe cases, the researchers report. They are partially linked to the virus entering the intestinal cells, which leads to changes in their normal functions, the research team explains.
Decrease in bacteria producing short-chain fatty acids
In addition, recent studies indicate significant changes in these individuals’ gut microbiota, including a decrease in the number of bacteria that secrete short-chain fatty acids (SCFAs) through fermentation of fiber. Short-chain fatty acids are important for the health of the colon and the maintenance of the intestinal barrier, explain the experts.
The researchers therefore decided to analyze whether SFCAs directly influence the infection of intestinal cells by SARS-CoV-2. Previous studies had suggested that changes in the gut microbiota could modify the immune response of infected individuals. Using colon tissue samples and tests on the epithelial cells that line the intestine and are in close contact with the intestinal microbiota, the team examined how the tissue samples react to an infection with SARS-CoV-2 in different scenarios.
The tissue samples or cells were treated with a mixture of acetate, propionate and butyrate, among other things, compounds that are produced by the intestinal microbiota during the metabolism of SCFAs contained in fiber, explain the researchers.
Protective function of the intestinal microbiota?
“In previous studies in animals, we found that compounds produced by the gut microbiota help protect the organism against respiratory infections. The model used there was the respiratory syncytial virus, which causes bronchiolitis (inflammation of the small airways in the lungs) and often infects children. Similar results were obtained by other research groups in studies of various respiratory diseases, ”reports study author Patrícia Brito Rodrigues from the University of Campinas (UNICAMP) in one Press release.
No reduced viral load
In the current study, however, “the viral load was not reduced by the short-chain fatty acids and was the same in the cells and tissues treated with SCFAs as in the untreated samples,” says study author Professor Raquel Franco Leal from the School of Medical Sciences (FCM) the UNICAMP. In addition, the treatment did not change the viral load in the colon biopsies or in the cells, and there were no changes in the permeability or integrity of the cell walls, the team reports.
Nevertheless, positive effects can be determined
However, treated intestinal biopsy samples showed a significant decrease in the expression of the gene DDX58 (a receptor of the innate immune system that recognizes viral nucleic acids and activates a signal cascade that leads to the production of pro-inflammatory cytokines) and of the so-called interferon lambda receptor, the antiviral activity mediates, so the expert. In addition, there was a decrease in the expression of the TMPRSS2 protein, which is important for the virus to penetrate the cell.
“This does not rule out the possibility of a significant effect of SCFAs on infection by SARS-CoV-2. The antiviral effects could depend on the interaction with other cells in the organism. We will continue our studies in animal models, as the effect of these compounds on infection may depend on a more complete system rather than samples that we used in vitro (isolated cells and tissues), ”explains Rodrigues.
“Changes in genes associated with virus recognition and response during intestinal infection could be relevant for the start of the inflammatory chain. In this context, it will be important to deepen the analysis of the effects of SCFAs on these parameters as this could be important in severe stages of the disease, ”adds Professor Leal.
So far, however, the results indicate that the changes in the composition of the intestinal flora of people with COVID-19, and in particular the short-chain fatty acids, do not counteract the SARS-CoV-2 infection in the intestine, summarize the researchers. A diet rich in fiber therefore does not have a protective effect in this way. (as)
Author and source information
This text complies with the requirements of specialist medical literature, medical guidelines and current studies and has been checked by medical professionals.
- Lívia Bitencourt Pascoal, Patrícia Brito Rodrigues, Lívia Moreira Genaro, Arilson Bernardo dos Santos Pereira Gomes, Daniel Augusto Toledo-Teixeira et al .: Microbiota-derived short-chain fatty acids do not interfere with SARS-CoV-2 infection of human colonic samples , in Gut Microbes (veröffentlicht 08.02.2021), Gut Microbes
- Research Foundation of the State of São Paulo, André Julião: High-fiber diet may play a role in controlling the inflammation associated with COVID-19 (veröffentlicht 31.03.2021), São Paulo State Research Support Foundation
This article is for general guidance only and is not intended to be used for self-diagnosis or self-treatment. He can not substitute a visit at the doctor.