Obstructive sleep apnea (OSA) is a highly prevalent and heterogeneous sleep disorder characterized by recurrent upper airway collapse during sleep, resulting in intermittent hypoxia, sleep fragmentation, sympathetic activation, and increased cardiometabolic risk. Although obesity is the most recognized modifiable risk factor, growing evidence indicates that nutritional factors influence OSA through mechanisms extending beyond body weight regulation, including systemic inflammation, oxidative stress, endothelial dysfunction, gut microbiota alterations, and metabolic dysregulation. The emergence of precision medicine and incretin-based therapies has further highlighted the need to integrate personalized nutritional approaches into OSA management. A literature search was conducted in PubMed/MEDLINE, Scopus, and Web of Science to identify experimental studies, observational studies, randomized clinical trials, systematic reviews, meta-analyses, and international clinical guidelines addressing nutritional mechanisms, dietary patterns, gut microbiota, chrononutrition, incretin-based therapies, and precision nutrition in adults with OSA. Current evidence suggests that nutritional interventions may influence OSA through multiple biological pathways beyond weight reduction. Mediterranean and DASH dietary patterns are associated with favorable cardiometabolic effects, while dietary fiber, polyphenols, omega-3 fatty acids, and other antioxidant compounds may modulate pathways related to inflammation, oxidative stress, endothelial function, and metabolic regulation. However, evidence directly demonstrating improvements in objective respiratory outcomes remains limited and heterogeneous. Emerging research also suggests potential roles for gut microbiota modulation and chrononutrition in metabolic and sleep regulation, although most evidence remains mechanistic, observational, or indirect. In addition, glucagon-like peptide-1 receptor agonists and dual incretin agonists have demonstrated clinically relevant reductions in body weight and OSA severity, providing opportunities for integration with nutritional management. Nevertheless, evidence supporting phenotype-specific and biomarker-guided nutritional interventions remains insufficient. Nutrition represents a promising adjunctive strategy in the multidisciplinary management of OSA by targeting inflammatory, metabolic, vascular, and microbiome-related mechanisms that extend beyond weight loss alone. Future research should focus on precision nutrition approaches integrating metabolic phenotyping, biomarkers, gut microbiota, and digital health technologies to optimize personalized treatment and improve long-term clinical outcomes.
