Intestinal microbiota: a key player in health and disease

The intestinal microbiota, a complex ecosystem made up of billions of micro-organisms, plays a fundamental role in our health. Numerous scientific studies have highlighted its influence on a range of pathologies, from cardiovascular disease and neurological disorders to cancer and diabetes.

How does this invisible ecosystem impact our well-being? Can we prevent certain diseases by taking care of our microbiota? This article explores the links between microbiota and health through the most recent discoveries.

The intestinal microbiota and chronic diseases

The intestinal microbiota, a veritable living ecosystem, influences many essential biological processes. Its imbalance, known as dysbiosis, can contribute to the development of various chronic diseases. Recent research has highlighted the close link between the composition of the microbiota and pathologies such as cardiovascular disease, diabetes and colorectal cancer. Understanding these interactions opens the way to new therapeutic approaches. These are based on modulating the microbiota to prevent or alleviate these conditions. Let’s explore how this invisible world impacts on our day-to-day health.

The role of the gut microbiota in cardiovascular disease (atherosclerosis)

Atherosclerosis, the cause of many heart diseases, is partly due to our eating habits and an imbalance in our microbiota. According to a study conducted by the Université Paris Cité and Inserm, a high-fat, low-fibre diet leads to systemic inflammation due to the migration of immune cells from the intestine to the arteries. This inflammation then exacerbates the formation of atherosclerotic plaque, increasing the risk of heart attack and stroke. In view of this, a balanced diet rich in fibre appears to be a natural solution for maintaining cardiovascular health.

Intestinal microbiota and autism spectrum disorders

There is growing interest in the link between microbiota and autism. A study by the University of Arizona, published in 2022, revealed that a transfer of intestinal microbiota from healthy donors significantly improved the symptoms of 18 autistic children. Two years after treatment, the severity of gastrointestinal disorders was reduced by 80% and autistic symptoms by 24%. This breakthrough opens the way to new therapeutic approaches based on modulating the microbiota, in particular via specific probiotics.

Colorectal cancer: an influence on post-surgery healing

Colorectal cancer, the second leading cause of cancer deaths in France, is mainly treated by surgery. However, up to 15% of patients who undergo surgery have intestinal leaks at the suture. A study conducted by the University of Montreal has shown that the composition of the microbiota directly influences the healing process. Certain pro-inflammatory bacteria, such as Alistipes onderdonkii kh 33, increase the risk of complications, while others, such as Parabacteroides goldsteinii kh 35, promote healing. Modifying the microbiota before surgery, using targeted probiotics and prebiotics, could therefore improve post-operative results.

Microbiota and mental health: the brain-gut link

The link between the brain and the gut, often referred to as the microbiota-gut-brain axis, is attracting growing interest in the field of mental health. Numerous studies show that the gut microbiota influences our emotions, our moods and even our behaviour. This connection is based on complex biochemical exchanges. These involve neurotransmitters and metabolites produced by intestinal bacteria. An imbalance in the microbiota can disrupt these communications and contribute to the onset of psychological disorders such as depression or anxiety. Let’s find out how this symbiosis between the gut and the brain impacts our mental well-being.

The intestinal microbiota as a factor in depression

Long regarded as a purely psychological disorder, depression appears to be closely linked to the gut microbiota. In 2020, the Institut Pasteur, Inserm and the CNRS demonstrated that chronic stress modifies the microbiota and causes a reduction in endocannabinoids in the brain. These molecules, which are essential for regulating emotions, play a role similar to that of THC, the main component of cannabis. Their absence leads to a drop in mood and withdrawal.

Psychobiotics and diet: a natural approach

In the light of these findings, scientists are exploring the use of psychobiotics (probiotics beneficial to the brain) as a complement to antidepressant treatments. A study by the University of Lublin in Poland also recommends a diet rich in fibre, polyphenols and vitamins B12 and D. This natural approach, combined with moderate physical activity, could reduce the symptoms of mild depression and prevent relapses.

Microbiota, metabolism and longevity

The intestinal microbiota plays a fundamental role in regulating metabolism and the ageing process. By participating in the digestion of food, the production of nutrients and the modulation of the immune system, it helps to maintain a balance that is essential to our health. However, an imbalance in this ecosystem can encourage the onset of metabolic disorders such as type 2 diabetes or accelerate cell ageing. Conversely, preserving the diversity and richness of the microbiota could prolong life in good health. Let’s explore how this invisible little world influences our metabolism and longevity.

The intestinal microbiota and type 2 diabetes

Type 2 diabetes, which affects 3.5 million people in France, is also influenced by the microbiota. A Franco-Swedish study published in Nature in 2020 revealed that people with pre-diabetes or diabetes show bacterial depletion and high levels of imidazole propionate in the blood. The researchers suggest that by enriching the microbiota with probiotics and symbiotics, it may be possible to reduce fasting blood sugar levels and prevent the onset of diabetes. A diet based on unprocessed products rich in fibre also plays a key role in this balance.

Ageing and gut microbiota: the key to healthy longevity

As we age, the composition of our microbiota changes, influencing our health and longevity. A major study conducted by the Institute for Systems Biology (ISB) in Seattle analysed the microbiota of 9,000 people aged between 18 and 101. The results show that people who age in good health have an increasingly unique microbiota. This microbiota is capable of producing metabolites such asindole (which prolongs life in mice) and phenylacetylglutamine (which is very common in centenarians). Maintaining a high level of bacterial diversity therefore seems essential for preventing age-related diseases and prolonging life in good health.

Sport and the intestinal microbiota: a winning combination for health

Physical activity also influences the composition of the microbiota. A review of studies conducted by the University of Bari in 2022 shows that sport promoteseubiosis, a state of balance in the microbiota.
However, excessive training, particularly among professional athletes, can upset this balance(dysbiosis) and impair performance. To avoid such imbalances, experts recommend a diet rich in fibre and, if necessary, probiotic supplements.

Conclusion

The intestinal microbiota is a key player in our health, influencing not only chronic diseases (cardiovascular disease, diabetes, cancer) but also our mental well-being and longevity. Recent scientific discoveries are paving the way for new therapeutic approaches based on modulating the microbiota.
To preserve this fragile balance, it is essential to adopt a varied diet, rich in fibre and fermented foods, while practising regular physical activity. Taking care of your microbiota means investing in your long-term health.

Source:

• https://www.pasteur.fr/fr/journal-recherche/actualites/explication-effets-du-microbiote-intestinal-notre-organisme
• https://www.inserm.fr/dossier/microbiote-intestinal-flore-intestinale/
• https://www.inrae.fr/dossiers/microbiote-intestinal-notre-nouvel-allie-sante