Association between plant-based diets and incident dementia: results from prospective cohort studies and a meta-analysis
Year: 2026
Type: review
Abstract: BACKGROUND: Plant-based diets are increasingly advocated for their health benefits, yet their associations with dementia risk remains inconclusive. We evaluated the associations between plant-based dietary patterns and dementia risk across three prospective cohorts and a meta-analysis. METHODS: Cohort analyses included the Health and Retirement Study (HRS; N = 6642), Framingham Heart Study Offspring cohort (FOS; N = 3045), and Whitehall II study (WHII; N = 8219). Participants were aged ≥45 years and free of dementia at baseline. The overall plant-based diet index (PDI), healthful plant-based diet index (hPDI) and unhealthful plant-based diet index (uPDI) were calculated from validated food frequency questionnaires. Further, a meta-analysis was conducted incorporating data from 5 cohort studies (N = 207,981). RESULTS: In the cohort analyses, 891 incident dementia cases were identified over 166,762 person-years. In multivariable-adjusted Cox proportional hazard models, higher scores in PDI and hPDI were associated with lower risk of dementia (highest vs. lowest tertile: pooled HR for PDI = 0.70, 95% CI, 0.53-0.92, p for trend <0.001; pooled HR for hPDI = 0.71, 0.48-1.06, p for trend = 0.03). Main contributors to lower risk were higher intake of vegetables, nuts, tea or coffee, and legumes. Conversely, higher uPDI was associated with higher dementia risk (highest vs. lowest tertile: pooled HR = 1.42, 1.19-1.70, p for trend <0.001). In the meta-analysis, individuals in the highest hPDI tertile had 21% lower dementia risk, and those in the highest uPDI tertile had 24% higher risk. CONCLUSIONS: The healthful plant-based diet was associated with lower risk of dementia, whereas the unhealthful plant-based diet was linked to higher risk. These findings support recommendations to adopt diets rich in healthy plant foods for dementia prevention.
Authors: Jie Shen, Hui Chen, Yiying Gong, Yuhui Huang, Minyu Wu, Yuxuan Gu, Tian Wang, Luigi Fontana, Shuang Rong, Shujiao Qian, Maurizio Tonetti, Xiaoran Liu, Changzheng Yuan
Institutions: Harvard University, Second Affiliated Hospital of Zhejiang University, Zhejiang University, Nanjing Normal University, The University of Sydney, Royal Prince Alfred Hospital, University of Science and Technology of China, Shanghai Jiao Tong University, Shanghai Ninth People's Hospital, Rush University Medical Center
Language: English
Topic: Nutritional Studies and Diet
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $4,060
Funder: Alzheimer's Association
Award: G2568008354
OpenAlex ID: W7124869600