How to take care of your intestinal microbiota on a daily basis?

We hear a lot about the intestinal microbiota, but what exactly are we talking about?

The intestinal microbiota is all the microbes that line our digestive tract. By microbes, we must understand bacteria essentially; it is estimated that there are 30,000 billion of them in the intestine. But we are also carriers of yeasts, archaea and viruses, in particular bacterial viruses (which we call bacteriophages and which are also found in large quantities in the digestive tract). In short, our intestine contains a veritable microscopic bestiary.

Which organs are involved?

Regarding the gastrointestinal microbiota, the microbial territory extends from the stomach to the colon via the small intestine. But, few organs escape the microbiota in reality. All internal (mucosal) and external (skin) surfaces of the body are also colonized by microbiota. This is why we should rather talk about microbiota because ultimately many organs have their own microbiota which has a very specific composition depending on the anatomical site concerned: cutaneous, pulmonary, salivary, vaginal microbiota, etc.

Why is it so important for our health to take care of it?

In the past, we talked about intestinal flora. Today we are talking about the intestinal microbiota. These two terms mean the same thing. On the other hand, the term microbiota implies an additional notion that we have understood thanks to research carried out intensively over the past fifteen years: that of functions, in other words the microbiota “does things”. The notion of flora was quite passive: we recognized a role for intestinal bacteria in digestion and that was hardly all. Currently, the list of roles or functions played by the intestinal microbiota is quite impressive. Its influence goes beyond simple digestion, contributing to numerous regulatory mechanisms in the body. To name only the most important in addition to digestion: the renewal of the intestinal mucosa, the synthesis of essential compounds (vitamins, essential amino acids, neurotransmitters,

anti-inflammatories, short-chain fatty acids, etc.), the regulation of immune balance, metabolism, and even mental health. In short, the microbiota plays a fundamental role in human physiology. It also plays a role in the development of certain diseases and, more surprisingly, it can influence the effectiveness as well as the toxicity of drugs.

How can we take care of it on a daily basis?

It’s ultimately quite simple to take care of your microbiota:

– have a balanced diet: consume foods rich in fiber, such as fruits, vegetables, whole grains, and legumes. Fermented foods (yogurt, kefir, buttermilk in Brittany, sauerkraut, kimchi) are also beneficial because they contain probiotics.

– Limit the use of antibiotics: they can disrupt the balance of the microbiota because they do not distinguish between pathogenic and beneficial bacteria. The interest is twofold because it helps curb the pandemic of antibiotic resistance.

– Avoid foods that are too fatty and processed: a diet too high in saturated fats and refined sugars can alter the composition of the microbiota and promote inflammation and metabolic diseases.

– Have good oral hygiene and consult your dentist regularly: Good oral health corresponds to a balanced oral microbiota which is also important for general health. Regular cleanings can help prevent oral infections and promote a healthy oral microbiota.

– Manage stress: Chronic stress and a lack of sleep can disrupt the balance of the microbiota.

– Do physical exercise: Regular physical activity can also have a beneficial effect on the diversity of the microbiota and strengthen the immune system.

Is there a way to know how our microbiota is doing, a kind of test?

Paradoxically, after everything we have just seen, the answer is no. We are still at a stage where we are far from having understood how the microbiota works because it is something very complex; This is why research must be pursued intensely. This is also what we do at Brest University Hospital, within the Brest Center for Microbiota Analysis (CBAM), whose aim is to support doctors in enriching their clinical research projects with the analysis of microbiota. Some private laboratories or start-ups, riding the microbiota wave, offer tests to the general public. We can do them if it’s fun and we have money to spend, but in practice it is of no medical use today and without any benefit for individual health at this stage of knowledge. With a working group from the French Society of Microbiology, which I coordinate with other microbiologist colleagues, we have alerted (2) to the false promises of these microbiota tests which deliver overinterpretations of results and provide unfounded therapeutic advice therefore potentially dangerous. These concerns are shared by experts in the field. Notably the French National Society of Gastro-Enterology (SNFGE) which has declared that tests based on the analysis of the intestinal microbiota have no clinical interest and should not be prescribed by doctors.

(1) Head of department in the Department of Infectious Agents at the Brest Center for Microbiota Analysis (CBAM) – Brest University Hospital.