AbstractBackgroundPlant‐based diets have been associated with a lower risk of several chronic diseases, but the relationship with PD is unknown.ObjectivesWe examined the association of three different plant‐based diets with PD incidence in the UK Biobank cohort.MethodsWe conducted a prospective study among 126,283 participants from the UK Biobank cohort. Three plant‐based diet indices (overall plant‐based diet index, PDI; healthful plant‐based diet index, hPDI; and unhealthful plant‐based diet index, uPDI) were derived from 24‐hour dietary recalls based on 17 food groups. Multivariable Cox regression models were used to estimate the risk of PD across quartiles of the PDIs and for each of the food groups that constituted the score. Further analyses were carried out to assess potential heterogeneity in associations between hPDI and PD across strata of some hypothesized effect modifiers.ResultsDuring 11.8 years of follow‐up (1,490,139 person‐years), 577 cases of PD incidence were reported. After multivariable adjustment, participants in the highest hPDI and overall PDI quartile had lower risk of PD (22% and 18%, respectively), whereas a higher uPDI was associated with a 38% higher PD risk. In food‐based analyses, higher intakes of vegetables, nuts, and tea were associated with a lower risk of PD (28%, 31% and 25%, respectively). Stratifying by Polygenic Risk Score (PRS), results were significant only for those with a lower PRS for PD.ConclusionsFollowing a healthful plant‐based diet and in particular the inclusion of readily achievable intakes of vegetables, nuts and tea in the habitual diet are associated with a lower risk of PD. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.