Feeding the microbiota with fiber reduces infections

Bacteria, viruses, parasites and non-pathogenic fungi… The human intestinal microbiota is made up of thousands of species of microorganisms, according to the National Institute of Health and Medical Research (Inserm). Some are beneficial, but others can be pathogenic for humans.

Eat fiber to promote the growth of good bacteria

In a new study published in the journal Nature Microbiologyscientists analyzed – using artificial intelligence – the composition of the intestinal microbiome of more than 12,000 people living in 45 countries, based on their stool samples.

Thus, they discovered that the “signature” of a person’s microbiome (the genetic data of the microbiota) could predict the risk of their intestine being colonized by enterobacteria. According to the Laroussethis family of bacteria brings together around twenty different genera. Among these, there are notably Klebsiella pneumoniae, Shigella et E.colibacteria that can be pathogenic for humans. In other words, there is a signature for the people who are least and most at risk of infection.

For the former, scientists identified 135 species of intestinal microorganisms present in people who did not have enterobacteria. Which means that their microbiota protected them against infections. They have certain “protective” species in common, such as bacteria Faecalibacterium. This produces short-chain fatty acids (which are beneficial) by breaking down fiber in the foods we eat. According to the authors, fiber intake, via diet, promotes the growth of good bacteria in the microbiota and limits the risk of infections. On the other hand, taking probiotics has no effect on this risk.

“Our results suggest that what we eat is potentially very important in controlling the likelihood of infection with [diverses] bacteria, including E.coli and Klebsiella pneumoniae, as this changes our intestinal environment to make it more hostile to invaders, underlines Dr Alexandre Almeida, main author of the study, in a communiqué. By eating fiber in foods like vegetables, beans, and whole grains, we can provide the raw material for our gut bacteria to produce short-chain fatty acids, compounds that can protect us from these disease-causing bacteria.”.

This study is important in a global context where antibiotic resistance is increasing and, in fact, the possibility of treating infections is decreasing. “Now the best approach is to prevent infections in the first place, and we can do this by reducing the opportunities for these disease-causing bacteria to grow in our gut”, explains Dr Alexandre Almeida.

Good and bad bacteria feed on the same nutrients

On the other hand, scientists identified 172 species of intestinal microorganisms characteristic of the microbiota where pathogenic enterobacteria could live. Furthermore, they observed that these bad bacteria needed the same nutrients to survive as the good ones. It is for this reason that they believe that taking probiotics does not necessarily reduce the number of enterobacteria present in the intestine, since they also nourish them.

There is still a lot of research to be done to understand all the secrets of the microbiota. But the main message of this study is to eat fiber as often as possible. Ideal, depending on the site mangerbouger.fris to consume at least 5 fruits and vegetables per day.