Olive oil, particularly virgin (VOO) and extra-virgin olive oil (EVOO), is a central component of the Mediterranean diet and has been associated with cardiometabolic, anti-inflammatory, and intestinal health benefits. Increasing evidence suggests that these effects may involve interactions with the gut microbiota, intestinal barrier, and host inflammatory pathways. This narrative review summarizes current evidence on the impact of olive oil, olive-derived phenolics, and olive oil-rich dietary patterns on gut microbiota modulation, barrier function, inflammatory bowel diseases, and related systemic outcomes. The available literature indicates that olive oil may interact with the gut ecosystem through both its oleic acid-rich lipid matrix and its minor phenolic fraction. VOO and EVOO appear more consistently associated than refined oils with microbial or microbial metabolite profiles related to saccharolytic metabolism, short-chain fatty acid production, mucus-layer dynamics, and anti-inflammatory intestinal environments. Olive-derived phenolics, including hydroxytyrosol, tyrosol, oleuropein derivatives, and oleocanthal, can undergo microbial biotransformation and may influence bile acid metabolism, epithelial barrier integrity, and inflammatory signaling. Whole EVOO evidence is strongest in experimental colitis models, whereas human evidence mainly supports effects on postprandial endotoxemia, lipid oxidation, and selected inflammatory markers. However, findings remain heterogeneous and depend on oil quality, phenolic composition, comparator fat, dietary context, and host condition. Well-controlled human studies directly comparing EVOO, VOO, refined olive oil, and oleic acid-rich controls are needed to clarify reproducible microbiota-mediated effects and their relevance to intestinal and systemic health.
Barrera-Chamorro et al. (2026) studied this question.