Eating fiber could protect you from infections. Here’s why. : Science Alert

Our body is not only human: it is home to billions of micro-organisms present in us or on us. In fact, there are more microbes in our guts than there are stars in the Milky Way. These microbes are essential to human health, but scientists still can’t figure out exactly what they do and how they help.

In a new study, published in Natural microbiologymy colleagues and I explored how certain gut bacteria can protect us from harmful bacteria – a group known as Enterobacteriaceae.

These bacteria include species such as Escherichia coli (E.coli). This is normally harmless in small amounts, but can cause infections and other health problems if it grows too much.

We have discovered that our gut environment – ​​shaped by things such as diet – plays an important role in controlling potentially harmful bacteria.

To reach this conclusion, we analyzed more than 12,000 stool samples from people in 45 countries. Using DNA sequencing technologies, we were able to identify and quantify the microbes detected in each sample. We found that the composition of the gut microbiome of people with Enterobacteriaceae was fundamentally different from that of people without it.

By analyzing these microbes and their genes, we could accurately predict (about 80% of the time) whether a person had Enterobacteriaceae in their gut. This showed us that the types of bacteria in our gut are closely linked to the ability of harmful species to take over.

Digging further, we discovered two groups of bacteria: those that thrived alongside Enterobacteriaceae (called “co-colonizers”) and those that were rarely found together (“co-exclusive”).

One type of co-exclusive bacteria, called Faecalibacterium, was found to be particularly important. It produces chemicals called short-chain fatty acids by breaking down various fibers found in our food. This in turn can prevent the growth of harmful bacteria like Enterobacteriaceae.

The presence of these fatty acids was one of the strongest signals we observed between co-excluders and co-colonizers. They have also been implicated in a wide range of health benefits, such as reduced inflammation and improved bowel function.

Another interesting observation from our study is that co-colonizers (bacteria that live alongside Enterobacteriaceae) were more adaptable. They had varying abilities to break down different nutrients and were able to survive in environments that are also suitable for Enterobacteriaceae.

This was especially surprising because previous studies in mice had shown that bacteria that eat the same types of food and nutrients would have difficulty living together in the gut.

This once again highlights the fact that intestinal environmental conditions (nutrients, pH, oxygen level) are the main factors that determine whether or not a person will be colonized with Enterobacteriaceae in their gut.

More effective than probiotics

Our findings could lead to new ways to prevent and treat infections without antibiotics. For example, instead of directly killing harmful bacteria (which can also harm good bacteria), we could strengthen co-excluders or create diets that support their growth.

This strategy could be more effective than taking probiotics directly, as it has already been shown that new bacteria added to the intestinal tract only live for a limited period of time in the intestine. We could also target specific pathways that harmful bacteria use to survive, making them less threatening.

Although our research provides new and important information, there is still much to learn. Many regions, including parts of South America and Africa, are underrepresented in microbiome studies. This limits our understanding of how gut bacteria vary in different populations.

Furthermore, although our study highlights important patterns and interactions, we do not yet fully understand the causes and mechanisms behind these relationships.

Future research will incorporate additional tools, such as metabolomics (studying chemicals produced by microbes) and transcriptomics (studying how genes are activated), to create a clearer picture of how the gut ecosystem works for our health.

Additionally, next steps should focus on designing studies to test whether specific types of diets (e.g., a high-fiber diet or a low-fiber diet) affect the incidence of potentially harmful bacteria and d other long-term illnesses.

By better understanding how microbes interact and communicate in our gut, we can develop more precise non-antibiotic therapies to protect against infections in the future.

Alexandre Almeida, Senior Researcher, University of Cambridge

This article is republished from The Conversation under a Creative Commons license. Read the original article.