A Fasting‐Mimicking Diet Affects the Inflammatory Response Following Periodontal Treatment: A Multi‐centre Feasibility Randomised Controlled Pilot Trial

Aim To investigate whether cycles of fasting‐mimicking diet (FMD), used as an adjunct to non‐surgical periodontal treatment, are feasible and could influence clinical and inflammatory responses, particularly with respect to C‐reactive protein (CRP). Materials and Methods Individuals with periodontitis were randomised to receive steps 1 and 2 of periodontal treatment, either following their regular diet (controls) or with three adjunctive 5‐day courses of FMD (test). Blood and gingival crevicular fluid (GCF) samples were collected to study the levels of inflammatory biomarkers, along with clinical parameters and patient‐reported outcome measurements (PROMs). All patients were followed up at days 1, 7, 45, 90 and 180 post treatment, and food diaries were completed. Exploratory repeated measures ANOVA and non‐parametric tests were used. Results Twenty‐seven patients completed the 6‐month follow‐up. Feasibility criteria were satisfied. Baseline serum high‐sensitivity (hs)‐CRP increased on Day 1 in both groups and then decreased. Exploratory longitudinal analyses indicated temporal changes in hs‐CRP and selected GCF biomarkers (including MMP‐8, CRP, IL‐6, IL‐1 α and IL‐1 β ), with descriptive trends towards lower values at later time points in the FMD group observed for hs‐CRP, MMP‐8 and IL‐6. No inter‐group periodontal clinical differences were detected. Only minimal adverse events were reported in the FMD group, with no inter‐group differences in PROMs and clinical outcomes. Conclusion Three cycles of FMD, adjunctive to step 2, were associated with a reduction of the inflammatory response after subgingival instrumentation, although these changes did not benefit clinical parameters. Given the exploratory nature of the analyses and the multiple comparisons performed, these findings should be interpreted with caution.