International experts establish first scientific definition of gut health

For the first time, global scientists have established a clear definition of gut health as: “A state of normal gastrointestinal (GI) function without active GI disease and gut-related symptoms that affect quality of life.” 

Although the 13 experts note that “gut health” is used increasingly across scientific, marketing, and public spheres, it has lacked a universal definition, coherent understanding, and assessment.

The new distinction encompasses a person’s physiological function, experience of symptoms, and the possibility of restoring gut health when symptoms and impacts are controlled despite a diagnosed digestive disorder.

According to the scientists, the lack of definition has led to narrow focuses, such as on the gut microbiome, while neglecting other gut health factors, such as digestive function and symptoms. They add that due to this, there have been no criteria to measure or track gut health over time.

Unified approach to gut health

The Nature Reviews Gastroenterology and Hepatology paper identified six domains of gut health: digestion, microbiome, gut barrier, immunity, metabolism, and gut-brain axis. Each can be measured in distinct ways, depending on the research goals. Symptoms can also be measured through validated assessment tools.

“Recent evidence showing how the gut microbiome has a major role in our overall health is just one way new insights on gut health are emerging,” says first author Maria L. Marco, Ph.D., professor at the University of California, Davis, US. 

“By defining gut health, we provide a framework to use the term in a more thoughtful and coordinated way between researchers, clinicians, and the broader public alike.”

The International Scientific Association for Probiotics and Prebiotics initiated the collaboration via a working group in September 2024. The group discussed the various domains of gut health and ways they could each be evaluated.

The group included scientists and physicians whose expertise encompassed gastroenterology, pediatrics, nutrition, immunology, and microbiology.

The experts believe that a definition is the starting point for understanding what supports gut and overall health across populations. The resulting paper presents a framework that can be used for designing studies and clinical gut wellness management.

Key points

The paper outlines essential points to consider for a meaningful understanding of gut health, such as combining an individual’s experience of GI activity with objective measures of gut function.

Also, GI disease does not exclude gut health, according to the experts. It can coexist, especially during periods of pathological remission. 

The paper adds that poor gut health is possible even without symptoms or measurable functional abnormalities. However, several measures of functions lack sufficient validation.

Additionally, the authors say that transient GI symptoms resulting from physiological responses to the environment, such as stomach issues when traveling, need to be distinguished from long-lasting conditions that hinder quality of life.

Lastly, they stress that risk factors that could impact gut health in the future are not fully understood in the present. Therefore, the researchers do not account for this in the established gut health definition.