Impact of Diet on the Microbiome-Immune-Brain Axis in Parkinson's Disease
NCT Number: NCT06463769
Status: NOT_YET_RECRUITING
Study Type: INTERVENTIONAL
Phases: NA
Conditions: Parkinson Disease
Interventions: BEHAVIORAL: 8 week predominantly plant-based New Nordic LPF-diet program|BEHAVIORAL: maintenance of the predominantly plant-based New Nordic LPF-diet
Sponsor: University of Kiel
Collaborators: University Hospital Schleswig-Holstein
Sex: ALL
Age: ADULT, OLDER_ADULT
Enrollment: 75
Study Design: Allocation: RANDOMIZED|Intervention Model: PARALLEL|Masking: NONE|Primary Purpose: TREATMENT
Start Date: 2025-05
Completion Date: 2028-07
Locations: Institute of Human Nutrition, Kiel, 24105, Germany|Kiel University, University Hospital Schleswig-Holstein, Kiel, 24105, Germany

Summary:
Habitual adherence to a predominantly plant-based diet, rich in low-processed food (LPF) has been associated with a reduced risk for development and slower progression of Parkinson's Disease (PD). This could be due to neuroprotective effects by modulation of the gut microbiota and decreased neuronal and metabolic inflammation. So far, the effect of a predominantly plant-based LPF-diet on the microbiome-immune-brain axis in patients with PD remains unknown. In addition, the influence of dietetic measures on the gut microbiome is variable and may depend on (long-term) adherence as well as on PD-specific factors and lifestyle.

The investigators hypothesize that compared to an average German diet, the predominantly plant-based New Nordic LPF-diet, as a culturally adapted diet, which is rich in fermentable fiber and phytochemicals, will have beneficial effects on the gut microbiome of patients with PD by increasing the abundance of short-chain fatty acid (SCFA)-producing bacteria (primary outcome) and will improve gut motility, metabolic resilience, and inflammation (secondary outcomes). Furthermore, the investigators postulate that a patient-centered dietary intervention program, including a multifaceted patient education and supported by a web-application, will lead to high adherence as a key determinant of long-term changes in the gut microbiome. This dietary intervention will be accepted by patients as a low-threshold treatment that balances personal benefits, therapeutic barriers and ethical concerns of early risk disclosure in PD.

Primary Outcome Measures: abundance of key SCFA-producing gut bacteria, analysis of stool samples, pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention
Secondary Outcome Measures: systemic inflammation markers, hsCRP and IL-6 in serum, pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention|metabolic resilience, modeling of one parameter (metabolic resilience) including information on postprandial glucose, insulin, triglycerides and NEFA following a mixed meal tolerance test, pre vs. post intervention (8 weeks)|gastrointestinal peptide-hormones, ghrelin, GLP-1, PYY, pre vs. post intervention (8 weeks)|energy balance, changes in body weight, pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention|energy partitioning, changes in body composition, pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention
Other Outcome Measures: clinical motor symptoms, clinical examination, pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention|clinical non-motor symptoms, clinical examination, pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention|gastric emptying, 13C-breath test, pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention|gastrointestinal transit time, using a test meal with food colouring and the time to colour appearance in stool, pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention|gut motility, functional visceral MRI, pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention|dietary adherence via serum markers, serum carotinoid and Trimethylamine oxid-levels will be combined and tertiles will be formed, pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention|dietary adherence via healthy Nordic food Index, healthy Nordic food Index using data from a food frequency questionnaire, pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention|food literacy effectiveness, self-perceived food literacy scale (questionnaire), pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention|patient acceptance, Parkinson's Disease Questionnaire (PDQ-39), pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention|patient quality of life, Ways of Coping Questionnaire (WCQ), pre vs. post intervention (8 weeks) + pre intervention vs. follow-up 6 months after completion of intervention