Plant-based natural products for symptomatic relief of Parkinson's disease: prevalence, interest, awareness and determinants

Natural health products (NHP) have emerged as a potential symptomatic therapeutic approach for persons with Parkinson's disease (PwP). The objective of this study was to quantify the prevalence of ever use of NHP, interest in plant-based NHP, awareness of potential herb-drug interactions, and how often NHP use was discussed by PwP with their healthcare professionals. We addressed these objectives by embedding a cross-sectional 4-item survey within a large population-based cohort of PwP (PRIME-NL study). Sixty-five percent (n=367) of the 566 participants who were contacted completed the survey. Of those participants, 132 (36%) reported having used NHP to alleviate Parkinson's disease (PD)-related symptoms, with coffee, cannabis and turmeric being the most popular. Overall, 12% (n=44) of PwP had used at least one NHP other than coffee or cannabis. Furthermore, 71% (n=259) participants expressed an interest in exploring the use of NHP, but only 39% (n=51) of NHP users were aware that these products could interact with PD medication. Finally, only 39% (n=51) of NHP users had discussed the use of NHP with their neurologist or PD nurse specialist. In a sensitivity analysis, we conservatively assumed that all non-responders to the survey had never used NHP and had no interest in exploring NHP. This rendered an estimated prevalence of NHP use of 23% and an estimated interest in exploring NHP of 46%. In conclusion, over one in three PwP has used NHP to alleviate symptoms of PD and the majority of PwP is interested in exploring the use of plant-based NHP. Most users had not discussed the intake of NHP with their PD healthcare professional and were unaware that these products could interact with PD medication. This study supports the need for evidence-based research on the properties of plant-derived therapeutics. ### Competing Interest Statement A.d.R.J. is supported by a Launch award from the Parkinson's Foundation (PF-Launch-937655), the Michael J Fox Foundation, internal funds from the Institute of Nutrition and Functional Foods (INAF), the Quebec Parkinson's Network, and funds from the Fondation CHU de Quebec. B.R.B. currently serves as Editor in Chief for Journal of Parkinson's disease; serves on the editorial board of Practical Neurology and Digital Biomarkers; has received honoraria from serving on the scientific advisory board for AbbVie, Biogen, and UCB; has received fees for speaking at conferences from AbbVie, Zambon, Roche, GE Healthcare, and Bial; and has received research support from the Netherlands Organization for Scientific Research, The Michael J. Fox Foundation, UCB, AbbVie, the Stichting Parkinson Fonds, the Hersenstichting Nederland, the Parkinson's Foundation, Verily Life Sciences, Horizon 2020, the Topsector Life Sciences and Health, the Gatsby Foundation, and the Parkinson Vereniging. N.M.d.V reports grants from The Netherlands Organisation for Health Research and Development (ZonMw) and The Michael J Fox Foundation. F.C. is a Fonds de recherche du Quebec-Sante research scholar and is supported by the Canadian Institutes of Health Research. S.K.L.D. has received funding from the Parkinson's Foundation (PF-FBS-2026), ZonMW (09150162010183), ParkinsonNL (P2022-07 and P2021-14), Michael J Fox Foundation (MJFF-022767) and Edmond J Safra Foundation. ### Funding Statement This research is part of the Proactive and Integrated Management and Empowerment in Parkinson's Disease (PRIME) project, which was funded by the Gatsby Foundation [GAT3676] as well as by the Ministry of Economic Affairs by means of the PPP Allowance made available by the Top Sector Life Sciences & Health to stimulate public-private partnerships. The Center of Expertise for Parkinson & Movement Disorders was supported by a center of excellence grant by the Parkinson Foundation. The authors declare that there are no conflicts of interest relevant to this work. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee of Radboud University Medical Center gave ethical approval for this work I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors