Microbiota and Metabolism: A deep dive into the gut-brain connection with Dr Giuseppe Togni

In recent years, the study of microbiota — the diverse community of microorganisms living inside, and on, our bodies — has gained immense attention, particularly regarding its impact on health and disease. Dr Giuseppe Togni, Head of the Department of Microbiology at Unilabs in Switzerland, recently shared his insights into this fascinating field, highlighting the profound connection between our gut microbes and conditions like obesity, diabetes, and mental health. 

Can you explain how the gut microbiota influences metabolism? 

Although much remains to be discovered, we already know quite a bit about the effect of a microbiota on human metabolism, as well as on physiological processes. Just as there is diversity between human beings, there is also diversity between microbiotas; there are microbiotas that are favourable and others that are unfavourable to our health.  

Our gut microbiota plays a role in the digestion of food, as well as in immune processes and in the production of hormones. Here is a simple example that demonstrates several physiological impacts of a favourable microbiota. The microbiota digests substances that the human body is unable to do alone, such as fibre and certain types of complex sugars. This generates additional nutrients that we can absorb, as well as the production of substances that have beneficial effects on our metabolic health, such as regulation of hunger, improvement of insulin sensitivity, and an anti-inflammatory effect. This in turn influences the secretion of hormones related to metabolism, such as insulin, leptin (satiety hormone) and ghrelin (hunger hormone). 

What are some of the most surprising findings from your research on microbiotas and obesity that might change the way we approach treatment? 

As previously mentioned, there are several microbiotas, including unfavourable ones that promote obesity. The differences between microbiotas relate to their ability to extract energy from food, metabolise lipids, produce hormones linked to appetite, as well as influence systemic inflammation (the latter also plays a role in the occurrence of type 2 diabetes). 

Understanding this has encouraged experts to explore the idea that modifying a microbiota could help to treat obesity. Among the most promising avenues, there is the development of probiotics (cocktails of live microorganisms) that can help to reduce inflammation, regulate appetite, and promote better nutrient utilisation. The field of prebiotics is also being explored, to find substances that promote the growth of good bacteria. The US National Center for Biotechnology Information’s clinical trials database shows that there are more than 200 different clinical studies being conducted around the world to evaluate the effect of probiotics and prebiotics in the treatment of obesity. Of course, the good old recommendation of a diet rich in fibre and low in fats and refined sugars remains immensely important. 

What recommendations would you make for maintaining a healthy microbiota? 

Just as a healthy lifestyle, a healthy diet, and physical exercise are the basis of good physical and mental health, they are also the basis of a healthy microbiota. It is necessary to aim for a diet that is rich in fibre — such as fruits, vegetables, and cereals; contains probiotics (which could also come from lactofermented foods); and is low in simple sugars, fats, and animal proteins. In addition, it is recommended to do regular physical exercise, which improves intestinal motility and helps to modulate the diversity and abundance of intestinal microorganisms. 

What role do you see for personalised medicine in the future of microbiota research, particularly concerning obesity and diabetes? 

Personalised medicine is the future of research when it comes to the microbiota and its interaction with human health. Understanding an individual’s unique microbiota is crucial for setting up a targeted therapy, such as one that uses probiotics and/or prebiotics that are adapted to the individual microbiota’s specific characteristics. 

Diagnosing and supporting a microbiota — preventatively and therapeutically — requires a collective and interdisciplinary effort across fields as varied as laboratory diagnosis, the development of adapted therapeutic products, and the psychological care of the patient.  

When it comes to laboratory diagnosis, analytical tools already exist and we now expect to see developments around the use of diagnostic data. At Unilabs, for example, we have selected several tools with which to pursue our ambitions in this space, and we are evaluating which analytical processes we can use alongside them to generate accurate and reliable solutions for our customers. Our aim is to be able to identify specific imbalances early, allowing for treatment before the symptoms of a disease appear. In addition, regular monitoring of the microbiota would allow therapeutic strategies to be adapted as a disease progresses, based on metabolic responses and changes in its composition. For the moment, these decision-making algorithms have not yet proven themselves, but we are confident that they will soon be more reliable. 

Could you share any exciting developments or upcoming studies in the field of microbiotas that you believe will significantly impact public health? 

The host-microbiota interaction plays a role in several areas. Obesity, diabetes, and inflammatory bowel disease have already been mentioned, but the list is much longer. The link between dysbiosis (an imbalance of microorganisms in the body) and colorectal cancer is currently being studied. The link between the gut microbiota and mental health also continues to generate great interest. As the concept of the gut-brain axis is increasingly explored, it is believed that there is a link between alteration of the microbiota and depression, anxiety, and autism. We can also mention studies on the link between the microbiota and longevity, aging, neurodegeneration, and cardiovascular diseases. Finally, observations seem to show that the microbiota has an influence on the effectiveness of certain drugs, such as anticancer drugs and antidepressants. 

Knowledge in all these areas will make it possible to develop preventative and therapeutic solutions, and will allow for greater personalisation of patient (and their microbiota) care. While much is yet to be explored, great progress has been made. For example, the first successes of faecal transplants in the treatment of recurrent Clostridium difficile infections, and the beneficial effects of probiotics in chronic inflammatory diseases and obesity, encourage us to believe that the therapeutic microbiota-based arsenal will be rapidly expanded.