Impact of Diet on the Microbiome-Immune-Brain Axis in Parkinson's Disease

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.