Nutrition as a preventive and adjunctive therapeutic modulator of rheumatoid arthritis and periodontitis: A narrative review

Abstract

Rheumatoid arthritis (RA) and periodontitis are interconnected chronic inflammatory diseases with overlapping immunological and inflammatory pathways. Increasing evidence highlights a bidirectional association wherein systemic inflammation, immune dysregulation, microbial dysbiosis, and metabolic disturbances amplify disease onset, severity, and progression, creating a self-reinforcing cycle. Their increasing population burden highlights the need for prevention-oriented, patient-implementable adjunctive strategies beyond pharmacological and periodontal care. This narrative review provides a timely interdisciplinary synthesis that reframes nutrition as a modifiable oral-systemic immune-metabolic factor linking both conditions, with relevance for dental and rheumatological practice. Epidemiological, mechanistic, and interventional studies were reviewed, focusing on dietary patterns, nutrients, and metabolic factors involved in inflammatory regulation, including cytokine signaling, oxidative stress, host immune responses, microbial interactions, and metabolic inflammation. Western diets, high in refined carbohydrates and saturated or omega-6-rich fats and low in fiber, together with excess adiposity, are associated with systemic and local inflammatory amplification and may aggravate RA and periodontal pathology. Conversely, Mediterranean and whole-food plant-based dietary patterns rich in fiber, antioxidants, omega-3 fatty acids, micronutrients, and phytochemicals may attenuate inflammatory signaling, enhance antioxidant defenses, modulate microbiome-host interactions, and support immunoregulatory pathways such as short-chain fatty acid production and regulatory T-cell activity. Nutritional strategies emphasizing whole, minimally processed foods may represent promising adjunctive approaches for managing RA and periodontitis by targeting shared inflammatory and metabolic pathways, reducing disease activity, and improving systemic and oral health outcomes. Prospective and interventional studies are needed to clarify causal mechanisms and evaluate the therapeutic potential of targeted nutritional strategies.