EditorialGut Microbiota and Its Importance on Human Health – The Need for Reliable Measurements to Assess the Microbial Gut Function and Its Correlated Pathologies

Lilian Terezinha Costa^*

• Federal University of Rio de Janeiro, Rio de Janeiro, Brazil

Since the beginnig of Human Microbiome Project (Nature 569, 641-648 2019) the gut microbiota has play an importante role in understanding human health and disease. New research has shown the correlation between microbial composition and physiological processes and pathological conditions, from metabolic disorders and inflammation to neurodevelopment and cancer. However, despite the remarkable progress in microbiome research, a persistent challenge remains: how to obtain reliable, reproducible, and clinically meaningful measurements of gut microbiota structure and function. This research topic, titled "Gut Microbiota and Its Importance on Human Health -The Need for Reliable Measurements to Assess the Microbial Gut Function and Its Correlated Pathologies," aimed to show the state of art of methodological challenges inherent in microbiome science. These contributions provide not only technical insights and innovations but also raise essential questions regarding standardization, reproducibility, and translational applicability.The issue brings a study on the stability of oral and fecal microbiomes under room temperature storage conditions, providing promising evidence that supports the feasibility of large-scale microbiome studies in real-world settings, even when ideal storage is not possible. The findings have critical implications for the design and logistics of populationbased microbiome research.In another original contribution, microbiome dynamics in response to delta9tetrahydrocannabinol (THC) treatment are explored in a murine model of obesity. The study demonstrates that specific bacterial features are predictive of weight changes, highlighting the potential of microbiome-informed modeling in metabolic interventions.Addressing the technical limitations of sampling, a novel approach is introduced via the SIMBA capsule, a minimally invasive device that enables precise spatiotemporal sampling of the small intestine microbiome. This technological innovation opens new avenues for studying host-microbiome interactions in regions previously di icult to access.The clinical implications of microbiome alterations are further explored in a pilot study linking gut dysbiosis and the reduced abundance of Faecalibacterium prausnitzii to pediatric cancer. Although preliminary, these findings point to potential microbial biomarkers for early detection or disease susceptibility.A population-based study adds to this issue by revealing that Lactobacillus colonization in infants is not only age-and breastfeeding-dependent, but also modulated by specific HLA haplotypes. These results provide critical insights into host genetic influences on microbial ecology, with direct relevance for probiotic design and personalized nutrition strategies.To deepen our understanding of what constitutes a "healthy" microbiome, a case report on a fecal microbiota super-donor o ers a rare glimpse into the complex microbial architecture associated with successful fecal transplantation, reinforcing the value of highresolution taxonomic profiling.Finally, a review on intestinal and fecal pH as a fast and accessible biomarker of gut function. The authors argue that pH, often overlooked, can serve as a surrogate for microbial metabolic activity and o ers potential as a diagnostic and monitoring tool in clinical practice.Together, all contributions highlight the multidimensional nature of gut microbiota research-spanning from sample handling and novel measurement tools to mechanistic insights and translational perspectives. Importantly, they converge on a common theme: the urgent need for reliable, standardized methodologies to ensure that microbiome data are not only scientifically robust but also clinically actionable.Hopefully this special research topic motivates further discussion, innovation, and clinical research in microbiome. We thank all the authors and reviewers for their valuable contributions and are confident that these works will serve as a meaningful resource for researchers and clinicians alike.