A personalized plant-rich, time-restricted nutritional intervention for motor and non-motor symptoms in Parkinson's disease: A randomized controlled trial
Journal of Parkinson's disease, vol.16, no.2, pp.351-361, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 16 Issue: 2
- Publication Date: 2026
- Doi Number: 10.1177/1877718x261422067
- Journal Name: Journal of Parkinson's disease
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, EMBASE, MEDLINE, Directory of Open Access Journals
- Page Numbers: pp.351-361
- Keywords: gut-brain interactions, inflammation, metabolism, neurodegeneration, non-motor symptoms, tremor, nutrition
- Dokuz Eylül University Affiliated: Yes
Abstract
BackgroundParkinson's disease is (PD) a progressive neurodegenerative disorder. This study investigated the effects of an individualized nutritional intervention based on the Ketoflex 12/3 protocol, in addition to standard medical treatment, on motor and non-motor symptoms in PD.Methods40 individuals with PD were included in the study, and participants were randomly assigned to intervention and control. All individuals were classified according to inflammatory, glycotoxic, toxic, and vascular biotypes. The intervention group was assigned a plant-rich diet with a low glycemic index, consistent with ketogenic principles, free of inflammatory effects, and including intermittent fasting. The primary endpoint was the change in motor symptoms measured by the Unified Parkinson's Disease Rating Scale part III (UPDRS-III) from baseline to six months. Secondary endpoints included apathy (Starkstein Apathy Scale), activities of daily living (ADL/IADL), and gastrointestinal function (Bristol stool scale).ResultsCompared with the control group, the intervention group showed a significantly greater improvement in motor symptoms as measured by UPDRS-III (-11.0 vs +2.1 points from baseline to six months; p < 0.001). Significant between-group differences were also observed for secondary endpoints, including apathy (Starkstein Apathy Scale), activities of daily living (ADL/IADL), and gastrointestinal function (Bristol stool scale), all favoring the intervention group. Spearman correlation analyses revealed significant negative correlations with ADL and UPDRS-III scores, particularly in individuals with an inflammatory phenotype.ConclusionsThe findings suggest an individualized nutritional approach may contribute to improvement in both motor and non-motor symptoms in PD. Larger, multi-center trials with extended follow-up are needed. Parkinson's disease is a complex condition that affects both movement and non-motor functions such as digestion, sleep, and mood. In this study, we examined whether a personalized, plant-rich eating approach, in which participants ate their daily meals within a fixed time window, could improve selected motor and non-motor symptoms in people with Parkinson's disease. Participants followed an individualized diet plan based on their metabolic characteristics, including guidance on what and when to eat, and received regular support over a six-month period.The results suggest that this nutritional approach was feasible in daily life and associated with improvements in motor symptoms and some non-motor features. However, as this was a pilot study with a relatively small number of participants, the findings should be interpreted with caution. Larger, well-controlled studies are needed to confirm these results and to better understand how personalized nutrition may support the management of Parkinson's disease.