Managing Constipation and Its Risks in Parkinson's Disease: Is There a Role for Dietary Fiber?

A common consequence of Parkinson's disease (PD) is constipation. Beyond its deleterious effect on the quality of life in affected persons, constipation is associated with gut microbiota dysbiosis and microbial-generated inflammatory metabolites, which may further disease progression. Management strategies are needed, and diet, specifically higher fiber dietary patterns or fiber supplements, may be recommended. However, therapeutic effectiveness and potential health benefits have been underexplored, and risks may be unappreciated. This perspective addresses whether high-fiber diets and fiber supplements to support laxation are efficacious, safe, and generally feasible for people with PD. Diverse sources of fiber from plant-based dietary patterns may be particularly critical for balancing microbiota and the microbial production of beneficial vs. inflammatory metabolites, although adherence to such dietary patterns may be challenging. Supplemental fiber may be needed to manage constipation symptoms. However, the potential safety issues related to fiber supplementation, such as appetite suppression, unintentional weight loss, and risk of malnutrition in the context of neurodegeneration, must also be considered. Slow colonic transit time and defecatory disorders of PD may be best managed with high intakes of bran or hull fibers resistant to microbial fermentation, which will significantly increase stool bulking. However, clinical trials are needed to confirm efficacy and dose-response.