During the 13th World Congress on Probiotics, Prebiotics and New Foods, held recently in Rome (italy) Microbiomepost sat down with Patrick Veiga, Gut Microbiome & Nutrition Research Director at INRAE (France).

One of the major challenges in probiotic research is the variability of clinical trial outcomes—some show clear benefits, while others fail to demonstrate efficacy. 

A key factor behind this inconsistency lies in the presence of “responders” and “non-responders.” On average, only about 60% of individuals benefit from probiotic supplementation, meaning trial results can fluctuate depending on participant recruitment. Recent research is beginning to uncover distinct profiles that differentiate responders from non-responders, including variations in gut microbiota, diet, and health status. However, predictive power remains limited, highlighting the need for larger, multi-dimensional cohorts that integrate microbiome, dietary, and clinical data. 

The future of probiotics may resemble a stratified or even personalized model, where individuals are matched with products likely to work for them—similar to how shoe sizes guide purchases today. Large-scale projects, such as the French Gut initiative, are paving the way toward this precision approach, aiming to build the evidence base for more robust and predictable probiotic interventions.