Stanford University
Parkinson's disease often causes constipation and changes in gut bacteria, but it is not known how quickly a daily fiber supplement changes gut physiology in people with Parkinson's, or how long any change lasts after stopping. This study will test how a daily fiber bar affects bowel function and gut inflammation in people with Parkinson's disease and in household members who live with them. Participants will eat one fiber bar (11 grams of fiber) each day for 3 months, then stop and be followed for one more month, for about 4 months in total. At three points (before starting, after 3 months of fiber, and one month after stopping), participants will collect a stool sample at home and mail it to Stanford in a provided kit, so no clinic visits are needed. Every week, participants will also fill out a short questionnaire about how often they have bowel movements, their bowel regimen, and they will complete a questionnaire about how bowel symptoms affect their daily life. In the lab, we will measure proteins in the stool that are signs of gut inflammation. We want to learn how fast these proteins change when fiber is added, whether changes last after fiber is stopped, and whether people with Parkinson's respond differently than their household partners. We expect that fiber will change gut inflammation and bowel function during the fiber period, and that these changes will differ between people with Parkinson's and their partners after the fiber bars are stopped. Results may help guide future research on diet and gut function in Parkinson's disease.
Rationale: Parkinson's disease (PD) is a progressive neurological disorder, and the biological drivers of disease progression remain poorly defined. Gastrointestinal (GI) dysfunction is among the earliest and most common non-motor features of PD, and constipation, dysbiosis, and an altered gut microbial composition are reported in up to \~80% of people with PD (PWP). PWP show reduced abundance of commensal taxa that produce metabolites, notably short-chain fatty acids (SCFAs), that are involved in intestinal motility, epithelial barrier integrity, and mucosal immune homeostasis. SCFAs are gen…
Inclusion Criteria Arm 1: * Diagnosed with Parkinson's disease by a movement disorders specialist * Age 18+ * Lives with a participant in this study enrolled or planning to enroll in Arm 2 * Not currently consuming a fiber supplement Inclusion Criteria Arm 2: * No history of neurodegenerative disease, including Alzheimer's disease, Parkinson's disease, Amyotrophic Lateral Sclerosis (ALS), Frontotemporal dementia, Multiple Sclerosis * Age 18+ * Lives with a participant in this study enrolled or planning to enroll in Arm 1 * Not currently consuming a fiber supplement Exclusion Criteria Arm 1…
NeuroFiber® prebiotic fiber bar (Sorridi Therapeutics): a vegan, plant-based whole-food bar with a proprietary blend of 14 prebiotic and whole-food fibers, formulated as a source of prebiotic fiber to support short-chain fatty acid-producing gut bacteria. Each bar is one serving (50 g) with 11 g of fiber. Participants eat one bar daily and may choose one flavor (Lemon Cranberry or Dark Chocolate Cherry) or receive an equal shipment of both. Ingredients include a prebiotic fiber blend, date paste, almonds, walnuts, whole-grain oats, pumpkin and chia seeds, fruit, coconut, green tea extract, and vitamins D3, B12, and E; Lemon Cranberry also contains cashews and flax seeds, and Dark Chocolate Cherry also contains cocoa products. No inulin or gums. Contains tree nuts. Donated by the manufacturer. Tolerability previously assessed in open-label pilot NCT07127120.