Modified Mediterranean diet effects on Parkinson's disease (MED-PARK): a single-centre randomised controlled trial protocol.

introductionOnly symptomatic treatments are available for patients with Parkinson's disease (PD), the second most common chronic neurodegenerative disease worldwide, and it is therefore imperative to identify disease-modifying interventions that can alter the course of the disease. Epidemiological studies in PD patients suggest that a Mediterranean diet is associated with better motor and non-motor symptoms, slower progression and reduced mortality. Few interventional studies, however, investigated the relationship between diet and PD severity and progression. This study aims to determine whether a Mediterranean nutritional intervention can benefit motor and non-motor symptoms experienced by PD patients. As a secondary aim, the effects of a modified Mediterranean diet on the immune system, metabolomics and microbiome will also be assessed. METHODS AND ANALYSIS: This is an interventional, non-pharmacological, superiority, randomised, controlled, single-centre, masked study with two parallel groups to evaluate the efficacy and safety of a modified Mediterranean diet on motor and non-motor patient-reported symptoms. PD patients meeting inclusion criteria will be enrolled (44 participants, aged between 40 years and 85 years), block-randomised and split into two parallel arms to either maintain their usual diet (control) or follow a modified Mediterranean diet for 6 months (intervention).Patient-reported symptomatology is the primary outcome, measured through the Movement Disorders Society Unified PD Rating Scale (MDS-UPDRS) I+II score. Secondary outcomes include the immunophenotype of circulating cells of the adaptive immune system, the nasal and faecal microbiome composition, faecal and urinary metabolites and the measurement of inflammatory and metabolic markers. Disease severity (MDS-UPDRS III), non-motor symptomatology (Non-Motor Symptoms Scale), participant's well-being (36-Item Short Form Health Survey), gastrointestinal symptomatology (Gastrointestinal Symptom Rating Scale and the Patient Assessment of Constipation Quality of Life) and intensity of dopaminergic replacement therapy (levodopa equivalents) will also be assessed. Evaluations will be conducted before the start and at the end of the intervention. ETHICS AND DISSEMINATION: The Ethical Committee 'Comitato Etico Territoriale Lombardia 5' first approved this study on 17 September 2024 Prot. Nr. 420/24. Findings will be disseminated via peer-reviewed research papers and conference presentations. TRIAL REGISTRATION NUMBER: NCT06705517.