Obesity is a risk factor for poor oral health. Here we test the hypothesis that weight gain due to high carbohydrate diets affects the inflammatory response in a mouse model of periodontitis.
300 male C57BL/6 mice (8 wk old) were fed ad libitum one of 15 isocaloric diets composed of differing percentages of total net metabolisable energy: protein (5, 10, 15%), carbohydrate (75, 70, 65%), fat was fixed at 20%. Mice were maintained on experimental diets for 18-19 weeks. The maxilla were dissected, stained and dried before taking standardised photographs. Periodontal bone loss was assessed by measurements of 3 positions of the second molar on both sides of the maxilla. Data were analysed, and ‘Geometric Framework’ surfaces generated using two generalised additive mixed models (GAMMs). In all models, the response variable was alveolar bone loss, and the identity of the animal from which the measurement was fitted as a random effect.
Increasing intake of total carbohydrates was associated with a linear increase in alveolar bone loss in mice (p < 0.01). On the other hand, protein intake had no effect on bone loss (p=0.29). The mean concentration of IL-1ß in gingival tissues was 1.046 ± 0.565 ng/mg total protein. There was a positive correlation between dietary carbohydrate content and pro-inflammatory cytokine IL-1ß, although the effect was not statistically significant (p= 0.08). There was no evidence that weight moderates the effect of diet on bone loss (linear mixed model,p=0.47).
This is the first study to explore macronutrient composition and types of carbohydrate on the development of natural occurring periodontitis. In the experimental model used an association between weight gain and the periodontitis associated bone loss was not found. However, increased carbohydrate intake significantly increased bone loss. Further research needs to show if weight gain is a risk factor for inflammatory diseases.