For years, gut health has been used liberally across research papers, probiotic marketing campaigns, and patient conversations—often without a consistent clinical definition. Now, a new 2026 consensus statement from the International Scientific Association for Probiotics and Prebiotics (ISAPP), published in Nature Reviews Gastroenterology & Hepatology, attempts to bring much-needed clarity to a term that sits at the intersection of microbiome science, GI physiology, and patient-reported outcomes.
For gastroenterologists, the key shift is this: gut health is no longer defined solely by the absence of disease—but by the presence of normal GI function and the absence of symptoms that meaningfully impact quality of life. Importantly, this means patients with conditions like IBD may still be considered to have “gut health” during periods of clinical remission.
The consensus moves beyond a microbiome-centric lens to frame gut health as a composite of multiple functional domains—including digestion, motility, epithelial barrier integrity, immune homeostasis, endocrine signalling, and the gut–brain axis. While biomarkers across these domains are emerging, the panel cautions that many currently lack validated clinical thresholds or correlation with patient outcomes—limiting their utility in routine practice.