Science continues to show that the gut plays a key role in health. This became even clearer during the 13th GMFH World Summit, held on March 15–16, 2025, in Washington, D.C. The event brought together healthcare professionals from around the world to discuss the theme — Microbiome Milieu: Diet, Drugs and Environment.
Here are the highlights from the four plenary sessions and thematic workshops.
Could gut microbes make you skinnier or heavier?
Have you ever considered that what you eat doesn’t just affect you, but also the microorganisms living inside you? This idea set the stage for the Summit, which began with an inspiring keynote lecture showing how our diet can influence not only our metabolism but also the gut microbiota.
This perspective was brought by Dr. Karine Clément, who presented the NutriOmics approach, integrating data on nutrition, metabolism, and gut microbiota. She showed that simple lifestyle habits—such as a varied diet, regular exercise, and avoiding smoking—can positively influence both metabolic health and microbial diversity. Dr. Clément and her team identified that individuals with lower microbial diversity tend to have a less healthy metabolism, but that dietary changes were able to improve this scenario.
In the future, advanced tools like omics sciences may help to personalize prevention and treatment strategies for obesity, considering the unique profile of each individual. For example, people with obesity have a lower abundance of Akkermansia, Faecalibacterium, and butyrate production potential, while having higher trimethylamine production potential, the latter being a gut microbiota-derived metabolite produced from dietary nutrients. Changes at the level of microbiota explain the significant variability between individuals in current obesity treatments and may offer clues to better selecting individuals who will benefit from pharmacological and dietary treatments, while also helping to integrate microbiome-targeted treatments as an add-on.
What we eat can help — or harm — our gut health
The first plenary session of the GMFH Summit 2025 brought together three experts who shared complementary perspectives on how diet and the gut microbiota can influence health — for better or worse.
Dr. Ashwin Ananthakrishnan opened the session by showing that our food choices can increase or reduce the risk of various diseases, since different components of the diet can directly impact the composition of the gut microbiota and, consequently, our health.
Next, Dr. Abigail Johnson offered a practical reflection on the methodological rigor needed to advance in this field. She pointed out that everything starts with a clear question: what do we want to discover? From there, it’s possible to define the right tools to collect dietary data and understand how this information can be combined with data on the gut microbiota. Johnson also acknowledged the current limitations of nutrition and microbiome research. Numerous nutrients that are not quantified on a food label (e.g., polyphenols found in most plant-based foods) can improve host health by feeding the gut microbiota, and scientists have begun considering how the type of food, cooking methods, and background diet affect gut microbes.
Wrapping up the session, Dr. Benoit Chassaing presented a study that caught the audience’s attention by showing the first study to show that reducing the consumption of food additives — especially emulsifiers, commonly found in ultra-processed foods — can help relieve symptoms of mild-to-moderately active Crohn’s disease. Findings in mice also showed that dietary emulsifiers can make it easier for certain intestinal bacteria to cross the intestinal barrier, increasing their potential to damage gut health. A clear message stood out: small changes in what we eat can have a big impact on gut health!
Beyond the gut: new clues into the relationship between the gut microbiota, cholesterol, and brain health
Did you know that your gut influences much more than just digestion? The second plenary session of the GMFH Summit 2025 delivered a clear message: the impacts of the gut microbiota go far beyond the intestine.
Dr. Bernd Schnabl presented surprising findings about a condition called auto-brewery syndrome — a rare situation in which the gut microbiota produces large amounts of alcohol, even without alcohol consumption, contributing to liver disease. He pointed out that the imbalance of these microorganisms can be treated in the near future with fecal microbiota transplantation, bringing hope to patients facing this diagnosis.
Next, Dr. Chenhao Li showed that certain gut bacteria, such as those from the Oscillibacter genus, are linked to cardiovascular risk factors, potentially affecting cholesterol metabolism and the balance of lipids in the body. It is interesting to note that cholesterol can be converted to coprostanol by the gut microbiota, and the presence of bacteria encoding the gene involved in this conversion is linked to lower levels of stool and blood cholesterol.
To close the session, Dr. Andrea Merchak highlighted a connection we don’t always consider in our day-to-day lives — the link between the gut and the brain. She explained that inflammation in the gut can directly impact brain health and may be associated with the development of neurodegenerative diseases. Key players involved in the gut-brain communication shaping the risk of brain inflammation and neurodegeneration are bile acids and gut inflammation. And she left an important message: our well-being doesn’t depend on a single factor, but rather on everything we are exposed to every day — diet, environment, lifestyle. According to Dr. Merchak, to fully understand these connections and turn knowledge into concrete actions, it is essential to invest in collaborative science, bringing together different fields to develop prevention and treatment strategies.
How to improve gut health? Why one-size-fits-all approaches don’t work
The afternoon of the first day of the GMFH Summit 2025 was dedicated to a series of thematic workshops, offering participants the opportunity to delve deeper into specific discussions about diet, gut microbiota, and health. In the first workshop, the speakers addressed how nutritional recommendations can be tailored according to each person’s health status. The second workshop introduced innovative perspectives by presenting new tools for studying the microbiome.
The third session focused on a very current question: Should we consume more fiber or less? The answer, as always in science, is that it depends. Fiber that comes from foods is the first choice and it seems prudent to increase the variety of non-processed plant foods to favour the growth of different bacteria. However, there is no one-size-fits-all diet advice, as the host’s health, immune status, diet, and gut microbiota have a significant impact on the final effect of fiber on health. Inulin can nourish gut bacteria, while psyllium and wheat fibers impact gut microbiota composition without promoting microbiota growth. Speakers also discussed how different dietary patterns can lead to distinct and stable states of the gut microbiota. Finally, the fourth workshop was dedicated to early life, exploring the ins and outs of probiotic administration to reduce the risk of necrotizing enterocolitis, sepsis, and death in preterm infants.
The sessions provided a more exclusive space for knowledge exchange among researchers, healthcare professionals, and students interested in understanding how scientific findings can be applied in everyday practice.
The gut ecosystem: more than just bacteria
Bacteria aren’t the whole story! On the second day, the third plenary session expanded the discussion to include the virome (the set of viruses in the gut), fungi, and the interaction between bacteriophages and bacteria.
The challenges of using bacteriophages therapeutically — viruses that infect bacteria — as an alternative to antibiotics, were discussed by Robert Schooley. He explained that, despite their promising potential, there are still many barriers to applying this strategy in practice, such as the difficulty in predicting their effectiveness, the need to protect them against stomach acid, and the risk of bacteria developing resistance to phages over time.
Dr. Kyla Ost then brought attention to a lesser-known component of the gut microbiome: fungi. She highlighted that, although they represent only 1 to 2% of the microbiota, Candida species play an important role in regulating the immune system. When in balance, they may contribute to metabolic health and promote beneficial immune responses, but when out of balance and in the form of hyphae (long, narrow, and tube-like filaments, they can promote inflammation and disease.
The presentations reinforced that, to fully understand the impact of the microbiome on health, it is essential to look beyond bacteria and consider viruses and fungi, underscoring the idea that gut health depends on a complex and interconnected ecosystem.
The gut microbiome and oncology
The fourth plenary session of the event focused on the interactions between the gut microbiota and oncology. Dr. Jonathan Peled discussed different strategies that can be used to modulate the microbiota during cancer therapies, such as the use of antibiotics, probiotics, prebiotics, and postbiotics, with the goal of improving treatment response and reducing side effects.
Next, Dr. Carrie Daniel-MacDougall emphasized the role of diet as a tool to support microbiota health, highlighting that a varied diet rich in prebiotic foods can help maintain microbial balance and promote symbiotic relationships between beneficial microorganisms. Diet is one of the most researched factors known to shape cancer risk and treatment outcomes through influencing the gut microbiota. Danie-MacDougall presented recent findings on how incorporating navy beans into the diet of colorectal cancer survivors may improve gut health and regulate immune and inflammatory processes. Ongoing human clinical trials are exploring how delivering prepared meals high in fiber to metastatic melanoma patients on immunotherapy may shape treatment outcomes.
Also in this plenary session, Dr. Cynthia Sears presented data on the presence of bacterial biofilms in cases of colorectal cancer. Dr. Sears showed that these structures are more frequent in tumors located in the right side of the colon and may contribute to cancer development by compromising the intestinal barrier and activating inflammatory pathways. The researcher also discussed possible mechanisms by which oral antibiotics and the bacterium Clostridioides difficile may be associated with colon cancer, reinforcing the importance of understanding the role of the microbiota in the prevention and treatment of this disease.
Closing the session, Dr. KC Huang presented new tools to investigate how gut bacteria colonize the body and interact with the environment. Dr. Huang highlighted that technologies such as metagenomic sequencing and bacterial lineage tracking allow these interactions to be monitored in detail, paving the way for increasingly precise discoveries about the impact of the gut microbiota on health.
The sessions left us with a powerful reminder:
The GMFH Summit 2025 made it clear that the gut microbiota is shaped daily by our choices: what we eat, the medications we use, and the environment we live in. These factors not only impact gut health, but also influence connections with different organs and systems throughout the body.
Science is advancing to turn these discoveries into practical recommendations, reaffirming that taking care of the gut is taking care of overall health.
