The potential role of gut microbiota, SCFAs, and intestinal permeability in obesity: A scoping review

Objectives: We aimed to summarize the relationships among obesity, gut microbiota dysbiosis, short-chain fatty acids (SCFAs), and intestinal permeability, and to explore thepotential dietary interventions that may reverse these imbalances. Methods: A scoping review was performed by searching Web of Science (WOS), PubMed, the Cochrane Library, and ScienceDirect from their inception until January 28, 2024. We applied predefined inclusion and exclusion criteria to select relevant articles for data extraction and synthesis. Results: Analysis of 48 articles revealed that obesity was associated with elevated Firmicutes, Proteobacteria, and Firmicutes/Bacteroidetes ratio, with a concomitant reduction in Bacteroidetes. At the genus level, Desulfovibrio and Streptococcus were enriched. SCFAs (especially butyric, propionic, and acetic acids) declined and intestinal permeability increased. Diet interventions, including probiotics, prebiotics, dietary patterns, and active food ingredients, reversed these shifts, promoting beneficial bacteria such as Bacteroides , Akkermansia , and Bifidobacterium , while reducing the abundance of Helicobacter . These changes in microbiota were accompanied by restored SCFA levels and improved intestinal permeability. These permeability changes involved alterations in physical (e.g., tight junction proteins), chemical (e.g., mucus production), and immune (e.g., inflammatory and oxidative markers) barriers, with most of these changes likely mediated by gut microbiota and SCFAs. Changes in G-protein coupled receptors (GPCRs) in the gut were also observed, with a decrease in GPCRs under obese conditions and an increase following dietary interventions. Conclusions: This review emphasizes the critical role of gut microbiota dysbiosis, reduced SCFAs, and impaired intestinal permeability in obesity, as well as the potential of dietary interventions to reverse these changes and improve gut health. These findings underscore the importance of multi-genera modulation based on microbiota ecological principles, and suggest future research on SCFA supplementation to offer new approaches for treating obesity linked to intestinal permeability.