Exploring Putative Causal Associations between Diet and Periodontal Disease Susceptibility

Introduction: Dietary factors may play an important role in periodontal health. However, current evidence from observational studies remains inconclusive. Objective: This study aimed to investigate the causal relationships between dietary exposures and periodontal disease risks using Mendelian randomization analysis. Methods: Large-scale genome-wide association study summary statistics for 20 dietary factors were obtained from the MRC-IEU consortium. Multivariable and univariable 2-sample Mendelian randomization analyses were performed to assess the causal effects of each dietary exposure on 6 periodontal outcomes, including gingivitis and periodontitis. Results: Genetically predicted higher dried fruit intake was significantly associated with reduced risks of acute gingivitis (odds ratio [OR]: 0.02; 95% confidence interval [CI]: 0.00–0.42; P = 0.01) and bleeding gums (OR: 0.96; 95% CI: 0.93–0.99; P = 0.01). Higher fresh fruit and water intake showed protective effects against chronic gingivitis (OR: 0.18; 95% CI: 0.04–0.91; P = 0.04 and OR: 0.15; 95% CI: 0.04–0.53; P = 0.00) and bleeding gums (OR: 0.95; 95% CI: 0.92–0.981; P = 0.00 and OR: 0.98; 95% CI: 0.96–0.99; P = 0.02). Alcohol intake frequency and processed meat intake were risk factors for bleeding gums (OR: 1.01; 95% CI: 1.00–1.02; P = 0.01 and OR: 1.05; 95% CI: 1.01–1.08; P = 0.00) and painful gums (OR: 1.01; 95% CI: 1.00–1.01; P = 0.00 and OR: 1.02; 95% CI: 1.01–1.03; P = 0.00). Most of the causal relationships between genetic predisposition to the specified dietary factors and periodontal diseases remained statistically significant (P < 0.05) after adjusting for genetic risks associated with dentures, smoking, and type 2 diabetes in multivariable Mendelian randomization models. Conclusions: The findings suggest potential protective effects of higher fruit and water intake against gingivitis and other periodontal problems, while alcohol and processed meat intake may increase the risks of periodontal disease. Our study provides preliminary causal evidence on the effects of diet on periodontal health and could inform prevention strategies targeting dietary habits to improve oral health. Knowledge Transfer Statement: This study suggests that fruit and water intake may protect against periodontal disease, while alcohol and processed meats increase risk, informing dietary guidelines to improve oral health.