From Diet to Oral and Periodontal Health: Exploring the Crucial Role of Nutrition—A Narrative Review

Background: The growing body of evidence linking dietary factors to oral and periodontal health is characterized by substantial heterogeneity in study design, dietary assessment methods, and reported outcomes, warranting a comprehensive narrative synthesis. Diet is a key determinant of oral and periodontal health, influencing inflammation, oxidative stress, salivary composition, and the oral microbiome. Objectives: This narrative review aims to synthesize current clinical, epidemiological, and mechanistic evidence on how dietary patterns and specific nutrients affect oral and periodontal health, focusing on inflammatory pathways, microbiome modulation, nutrient-dependent tissue mechanisms, and clinical outcomes. Methods: A structured narrative search was conducted in PubMed, Scopus, Web of Science, and Google Scholar (2000–2025). Studies examining diet, nutrients, the oral microbiome, caries, gingival inflammation, or periodontal disease were screened through a multistep process, resulting in 98 included articles. Results: High-sugar and ultra-processed diets trigger inflammation and oral dysbiosis, increasing caries and periodontal susceptibility. In contrast, nutrient-rich and anti-inflammatory diets improve immune regulation, support microbial balance, and are associated with better periodontal parameters. Conclusions: Dietary habits significantly shape oral and periodontal outcomes through interconnected metabolic, microbial, and immunological pathways. Integrating targeted nutritional counseling into dental care may strengthen prevention strategies and improve long-term oral health.