Exploring the associations between dietary nitrate and nitrite intake and markers of self-reported periodontal disease in the UK Biobank cohort

PURPOSE: Periodontal disease, an inflammatory condition affecting the tissue surrounding the teeth, has been associated with various systemic health issues. Dietary nitrate and nitrite are found in a range of plant and animal foods and, depending upon source, have been linked with both positive and negative health effects, including improved oral health with plant sources. This study aimed to investigate the associations between source-dependent (plant- and animal-sourced) nitrate and nitrite intake and odds of periodontal disease. METHODS: We explored cross-sectional and longitudinal associations between tertiles of source-dependent nitrate and nitrite intake and the odds of periodontal disease using multivariable logistic regression models (cross-sectional analyses) and generalised estimating equations (longitudinal analyses) in 158,778 and 83,026 participants, respectively, from the UK Biobank. Dietary nitrate/nitrite intake was estimated from 24 h dietary assessments and a comprehensive food composition database. RESULTS: Higher intake of plant-derived nitrate was associated with significantly lower odds of periodontal disease in cross-sectional (OR [95%CI]: 0.925 [0.894-0.958]) and longitudinal (OR [95%CI]: 0.880 [0.840-0.921]) analyses compared with lower intakes. A similar pattern of association was observed for plant-derived nitrite. Animal-derived nitrate intake was not associated with odds of periodontal disease. Higher intake of animal-derived nitrite was associated with significantly higher odds of periodontal disease in cross-sectional analyses only (OR [95% CI]: 1.043 [1.009-1.078]). CONCLUSION: Plant-derived nitrate and nitrite were associated with lower odds of self-reported periodontal disease, whilst animal-derived nitrite showed adverse associations in cross-sectional analyses only. Associations between dietary nitrate and nitrite with oral health outcomes may therefore depend on food source. Further mechanistic and intervention research is needed to test causality.