Dietary Fibre Modulates Body Composition, Blood Glucose, Inflammation, Microbiome, and Metabolome in a Murine Model of Periodontitis

<b>Background:</b> Dietary fibre plays a crucial role in metabolic regulation, inflammation, and microbiome composition. However, its impact on systemic and oral health, particularly in periodontitis, remains unclear. This study investigated the effects of high- and low-fibre diets on body composition, glycaemic control, inflammation, microbiome, and metabolome in a murine model of experimental periodontitis. <b>Methods:</b> Thirty-six male C57BL/6 mice were randomised to a high-fibre (40% fibre) or low-fibre (5% fibre) diet for eight weeks. Body weight, fat mass, lean mass, fasting blood glucose, serum inflammatory markers, alveolar bone loss, and root length were assessed. Oral and faecal microbiome composition was analysed using 16S rRNA sequencing. Metabolomic and short-chain fatty acid (SCFA) profiling was conducted using liquid chromatography-mass spectrometry (LC-MS). <b>Results:</b> Mice on the high-fibre diet exhibited significantly lower body weight (<i>p</i> < 0.0001), fat mass (<i>p</i> = 0.0007), and lean mass (<i>p</i> < 0.0001) compared to the low-fibre group. Fasting blood glucose levels were significantly lower in the high-fibre group (<i>p</i> = 0.0013). TNF-α and IFN-γ levels were significantly elevated in the low-fibre group (<i>p</i> < 0.0001), suggesting a heightened pro-inflammatory state. While alveolar bone loss and root length did not differ significantly, microbiome analysis revealed distinct bacterial compositions (PERMANOVA, <i>p</i> < 0.05), with fibre-fermenting taxa enriched in high-fibre-fed mice. Metabolomic analysis identified 19 significantly altered metabolites, indicating dietary adaptations. <b>Conclusions:</b> A high-fibre diet improves glycaemic control, reduces systemic inflammation, and alters microbial and metabolic profiles in experimental periodontitis. These findings highlight dietary fibre's role in modulating metabolic and inflammatory pathways relevant to periodontal and systemic diseases.