New framework established for defining prebiotics

The concept of prebiotics – defined as substrates that are selectively utilized by host microorganisms conferring a health benefit – was introduced in the scientific community nearly 30 years ago. Today, prebiotic substances have gained significant attention as potential ways to enhance health through the gut microbiota. But given the rapid recent expansion in high resolution microbiome research technologies, and scientists' growing understanding of the ways dietary compounds and nutrients might impact the microbiome, confusion for scientists and consumers has emerged around which substances have genuine prebiotic effects.

Now a group of eight leading international scientists has developed a comprehensive framework that outlines the criteria for establishing prebiotic status, providing much-needed clarity in this evolving field. This new expert recommendation, published in Nature Reviews Gastroenterology and Hepatology, addresses the key challenges related to scientific substantiation of prebiotics and offers practical guidelines for accurately identifying prebiotics and assessing their health effects. The publication resulted from collaborations coordinated through the International Scientific Association for Probiotics and Prebiotics (ISAPP).

The authors detail a clear scientific pathway for demonstrating prebiotic effects, emphasizing that prebiotics must meet several essential criteria. First and foremost, a prebiotic must be a well-characterized substance that provides a measurable health benefit. In addition, it must be selectively utilized by host microorganisms, show measurable effects on microbiome composition or function, have a plausible mechanism linking the microbiome changes to the observed health benefit, and be safe for its intended use. Importantly, at least one study in the target host is required to demonstrate both microbiome modulation and a health benefit concurrently.

Two of the most important challenges addressed within the paper are validation of selective utilisation within the complexity of the microbial ecosystem's response to a prebiotic intervention, as well as methods for delineating the mediation of health benefits via microbiome-based mechanisms.

The authors say that over time they hope regulatory and commercial approaches to prebiotics will increasingly align with the scientific criteria they specified.

The criteria provide a foundation for understanding what prebiotics are and how to substantiate them, which is essential for the field going forward. Our hope is that scientists around the world take a unified approach to demonstrating the prebiotic status of an ingredient, which will promote clarity and support informed decision-making around prebiotic products."

Prof. Robert Hutkins, lead author, University of Nebraska