Oral and Gut Microbiota Changes During Long-term Fasting in Humans (OralFast)

Buchinger Wilhelmi Clinic, University of Geneva, Switzerland, King's College London, ETH Zurich (Switzerland)

The aim of this longitudinal trial is to investigate the effects of a 10±3-day fasting period in 30 subjects. Changes in the oral and gut microbiota, halitosis, as well as inflammatory and antioxidative parameters and biomarkers of sulfur metabolism will be analysed.

Fasting has been linked with changes in gut microbiota as part of the physiological adaptation. Furthermore, associations have been described between oral disease and nutrition (diet rich in carbohydrates). The aim of the present longitudinal clinical study is to explore the effect of a 10±3-day fasting period on the oral and gut microbiota. 30 systemically healthy subjects attending the Buchinger Wilhelmi Clinics for fasting, will participate. Changes in oral microbiota will be assessed in plaque and saliva samples and a number of inflammatory markers will be analyzed in Gingival Crevicular fluid (GCF) and blood obtained before, during and after the fasting period. The changes in the oral microbiota will be associated to the composition of the gut microbiota. Changes in periodontal parameters and halitosis related to the fasting period will be further evaluated. Given the known association between sulfur metabolism and the redox status, parameters from the antioxidant status and oxidative damages will also be assessed.

oral microbiota, intestinal microbiota, inflammatory status, redox status, sulfur metabolism, halitosis

The participants will undergo a fasting program that includes the daily intake of 250 kcal under medical supervision.

Concentration of volatile sulfide compounds (hydrogen sulfide, methylmercaptan and dimethyl sulphide) using the OralChrome devise

Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas (Pg), Tannerella forsythia (Tf), Treponema denticola (Td), Parvimonas micra (Pm) and Prevotella intermedia (Pi) analysed by RT-q-PCR

using the S-sulfocysteine (SSC) method which is a HPLC-based method using automated precolumn derivatization with OPA and UV detection at 338 nm in serum and urine

Sillness & Loe, 1964: from 0 = no plaque to 3 = abundant plaque along the gingival margin, interdental spaces filled with plaque

Inclusion Criteria: Both subjects with periodontitis and healthy periodontium will be included. Signed informed consent Exclusion Criteria: Not able to sign the informed consent diagnosticated with cachexia, anorexia, nervosa, advanced kidney, liver or cerebrovascular insufficiency Smoking the intake of antibiotics within the last 8 weeks, as well as the intake of probiotics within the last 4 weeks periodontal treatment in the last 6 months chronic manifest psychical and psychiatric diseases participation in another study pregnancy or breastfeeding