Preventive Effects of a Cocoa‐Enriched Diet on Gingival Oxidative Stress in Experimental Periodontitis

Background: Oxidative stress affects the progression of periodontitis. Cocoa is a rich source of flavonoids with antioxidant properties, which could suppress gingival oxidative stress in periodontal lesions. The purpose of the present study was to investigate the effects of a cocoa‐enriched diet on gingival oxidative stress in a rat‐periodontitis model. Methods: In this 4‐week study, rats were divided into three groups (n = 8/group): a control group (fed a regular diet) and two periodontitis groups (fed a regular diet or cocoa‐enriched diet [10% of food intake]). Periodontitis was induced by ligature placement around the mandibular first molars. Serum levels for reactive oxygen metabolites were measured at baseline and 2 and 4 weeks. At 4 weeks, the levels of 8‐hydroxydeoxyguanosine and reduced/oxidized glutathione ratio were determined to evaluate gingival oxidative damage and antioxidant status, respectively. Results: Rats with experimental periodontitis that were fed a regular diet showed an increase in the level of serum reactive oxygen metabolites in a time‐dependent manner. These rats also had an increased 8‐hydroxydeoxyguanosine level and decreased reduced/oxidized glutathione ratio in the gingival tissue, inducing alveolar bone loss and polymorphonuclear leukocyte infiltration. Although experimental periodontitis was induced in the rats fed a cocoa‐enriched diet, they did not show impairments in serum reactive oxygen metabolite level and gingival levels for 8‐hydroxydeoxyguanosine and reduced/oxidized glutathione ratio. Alveolar bone loss and polymorphonuclear leukocyte infiltration after ligature placement were also inhibited by cocoa intake. Conclusion: Consuming a cocoa‐enriched diet could diminish periodontitis‐induced oxidative stress, which, in turn, might suppress the progression of periodontitis.