Ask the author session

Understanding how our gut influences our brain is one of the most exciting frontiers in metabolic and liver-related research. For people living with MASLD/MASH (formerly NAFLD/NASH), obesity, and metabolic dysfunction, new insights into the gut–brain–liver axis are emerging every year.

One particularly compelling example is the recent paper published in GUT by Dr. Virginia Mela and colleagues: “Microbiota fasting-related changes ameliorate cognitive decline in obesity and boost ex vivo microglial function through the gut-brain axis.”

In our latest Ask the Author session, Prof. Jean-François Dufour sat down with Dr. Mela to explore the study’s design, findings, and what they could mean for individuals at risk of fatty liver disease. The conversation is rich, accessible, and highly relevant for anyone interested in the interplay between nutrition, inflammation, cognition, and metabolic liver disease.

👉 You can watch the full interview on our website—don’t miss it.

A Closer Look: Three Diets, One Key Question

Dr. Mela and her team conducted a randomized controlled trial involving 96 participants with obesity. Participants were assigned to one of three well-defined dietary interventions for three months:

Mediterranean diet (rich in olive oil, fish, legumes, vegetables)
Ketogenic diet (very low carbohydrate, high fat)
Alternate-day fasting (restricted intake on fasting days; controlled intake on non-fasting days)

The goals?

To determine how these diets affect weight loss
To explore whether they can improve cognitive performance, given the well-established link between obesity and cognitive decline

All participants underwent detailed metabolic, inflammatory, microbiota, and cognitive assessments before and after the intervention period.

What They Discovered: Alternate-Day Fasting Stands Out

While all three diets produced similar weight loss—and the ketogenic diet led to the greatest reduction in fat mass—the alternate-day fasting diet had the most impressive effect on cognitive improvement.

Dr. Mela explains that this benefit appears to be driven by several biological changes:

1. Reduced systemic inflammation

Inflammatory markers fell significantly after the alternate-day fasting intervention, suggesting a broad anti-inflammatory effect.

2. Improved microglial function

Microglia—the brain’s resident immune cells—showed healthier, more functional behavior after exposure to participants’ post-diet biological samples.

3. Favorable shifts in gut microbiota

Alternate-day fasting increased specific beneficial bacterial taxa that correlated with cognitive improvements.

4. Increased riboflavin production

A standout finding was the rise in riboflavin, a microbiota-derived metabolite known for anti-inflammatory and immunomodulatory effects—potentially linking gut changes to brain improvements.

Prof. Dufour highlighted how elegant and multidimensional the study is, bridging microbiota composition, metabolites, brain immune cell activity, and cognition.

What Does This Mean for MASLD/MASH?

With new drugs entering the MASLD/MASH treatment landscape, lifestyle strategies remain essential. Dr. Mela emphasizes that dietary interventions like alternate-day fasting may play a powerful preventive role:

They help minimize metabolic dysfunction and inflammation—two key drivers of fatty liver disease progression. While diet alone may be insufficient in later disease stages, integrating such patterns early could reduce risk, support metabolic health, and potentially complement future pharmacotherapies.

Why You Should Watch the Full Interview

This conversation is not just about nutrition—it’s about how strategic dietary patterns reshape the microbiota, influence immune function in the brain, and potentially protect metabolic health.

Whether you’re:

living with MASLD/MASH,
a clinician advising patients,
a researcher in the metabolic field, or
simply someone curious about the gut–brain axis,

this interview offers science-based insights delivered in a clear and engaging way.

👉 Watch the full interview with Dr. Virginia Mela now here on the Swiss NASH Foundation website.
It’s an inspiring look at how dietary science continues to evolve—and how it may help us prevent and better understand metabolic liver disease.

In a recent “Ask the Author” session, Professor Stefano Romeo discussed his groundbreaking work on data-driven cluster analysis to identify distinct types of metabolic dysfunction associated with steatotic liver disease. The conversation highlighted a significant shift from “non-alcoholic” to “metabolic” in defining liver diseases, emphasizing a positive and more inclusive approach. This blog post delves into the key insights from the session, exploring the study’s design, findings, and implications for managing patients with Metabolic dysfunction-associated steatotic liver disease (MASLD).

Prof. Stefano Romeo answering to the questions of Prof. Jean-François Dufour.

Study Design and Methodology Professor Romeo’s study aimed to address the heterogeneity observed in Metabolic dysfunction-associated steatotic liver disease (MASLD). The research began with a simple clustering approach using six readily available clinical variables: HbA1c, triglycerides, LDL, age, BMI, and ALT . This unsupervised machine learning method identified three distinct clusters, two of which showed histological evidence of Metabolic dysfunction-associated steatotic liver disease (MASLD) .

Key Findings The study revealed significant differences between the identified clusters:

Cluster 1: Characterized by higher triglycerides and HbA1c levels, indicating more pronounced dyslipidemia and diabetes .
Cluster 2: Showed increased ALT levels, suggesting a more liver-specific disease .
UK Biobank Replication: The findings were replicated in the UK Biobank, confirming that the cluster with higher triglycerides and HbA1c was associated with more cardiovascular events, while the cluster with elevated ALT was primarily linked to liver-related events .

Causality between Liver Disease and Cardiovascular Events Further research explored the causal relationship between Metabolic dysfunction-associated steatotic liver disease (MASLD) and cardiovascular events using polygenic risk scores based on genes affecting fatty liver disease: TM6SF2 and PNPLA3 .

TM6SF2 and PNPLA3: Associated with lipoprotein retention, higher MASH and fibrosis, and lower cardiovascular disease risk .
Increased Lipogenesis: The group without lipoprotein retention showed an association with the entire spectrum of cardio-renal metabolic syndrome .

Two Distinct Phenotypes of MASLD The combined results from the cluster analysis and genetic studies suggest the existence of two distinct types of Metabolic dysfunction-associated steatotic liver disease (MASLD) :

Liver-Specific MASLD: Primarily affects the liver due to liver-specific mechanisms .
Systemic MASLD: Affects the entire body, with broader systemic implications .

Implications for Patient Management These findings have significant implications for how Metabolic dysfunction-associated steatotic liver disease (MASLD) patients are managed . Recognizing these distinct phenotypes allows for more targeted treatment strategies, addressing specific metabolic dysfunctions and reducing the risk of cardiovascular events in susceptible individuals .

Conclusion Professor Romeo’s work marks a significant advancement in understanding the complexities of Metabolic dysfunction-associated steatotic liver disease (MASLD). By identifying distinct metabolic subtypes and their associated risks, this research paves the way for more personalized and effective treatment approaches, ultimately improving patient outcomes .

Link to full article in Nature journal.

Tag: Ask the author

How Fasting-Driven Microbiota Changes May Protect the Brain in Obesity: A Fascinating Conversation With Dr. Virginia Mela