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Association between plant-based diets and incident dementia: results from prospective cohort studies and a meta-analysis
Jie Shen, Hui Chen, Yiying Gong, Yuhui Huang, Minyu Wu, Yuxuan Gu, Tian Wang, Luigi Fontana, et al.. The journal of prevention of Alzheimer's disease, 2026-01-20
Topic: Risk, prevention and care in population studies
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 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.
Key findings
- 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.
- 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).
- These findings support recommendations to adopt diets rich in healthy plant foods for dementia prevention.
Why it matters
In three cohorts plus a meta-analysis, eating more healthful plant foods was linked to lower dementia risk, while unhealthful plant-based diets were linked to higher risk. These are observational associations, so they support dietary recommendations but cannot prove that changing diet directly prevents dementia.
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Study details
- Study designmeta-analysis
- Participants207,981
- Effect sizePooled HR for dementia, highest vs lowest tertile: overall PDI 0.70 (95% CI 0.53-0.92); unhealthful PDI 1.42 (95% CI 1.19-1.70)
- Evidence strengthModerate
Limitations
Observational diet data from food-frequency questionnaires; residual confounding by overall health behaviour; dementia ascertainment methods differed between cohorts.
How this study scored 66/100
Published in a peer-reviewed journal, and it is a meta-analysis pooling many studies. We have no data on free to read, so that was left out: it earned 65 of the 98 points we could judge it on, which is 66 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (The journal of prevention of Alzheimer's disease) |
| Journal's citation record | 0 / 4 | The Journal of Prevention of Alzheimer s Disease: journal h-index 63 (OpenAlex, 2026-10-29) |
| Study design | 12 / 12 | A meta-analysis pooling many studies |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 5 / 5 | 2026 — within 1 year(s) of the newest study here |
| Sample size | 4 / 4 | 207,981 participants |
| Effect reported | 3 / 3 | Effect reported with a statistic (interval, p-value, ratio or similar) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | A review of other studies — randomisation is not credited here |
| Times cited | 2 / 7 | Cited 5 times (OpenAlex, 2026-10-10) |
| Citations per year | 1 / 5 | 2.5 citations a year over 2 year(s) since 2026 |
| Impact for its field and year | 4 / 6 | Cited 13.1× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 1 / 4 | Cited 5 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Changzheng Yuan: h-index 41 (OpenAlex, whole career) |
| Institution's track record | 3 / 3 | Harvard University: institution h-index 3,235 (OpenAlex) |
| Multi-centre collaboration | 3 / 3 | OpenAlex lists 10 institution(s) in 3 countries |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 41564649) |
| Free to read | — / 2 | Access not recorded — left out of this score |
| Points | 65 / 98 | Scored on 19 of 20 parts. We have no data for the rest, so they are left out: 65 of the 98 points we could judge it on is 66 out of 100. |
| Total | 66 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
- DOI: 10.1016/j.tjpad.2025.100457
- PubMed: 41564649
- Original source →
- Free full text: PubMed Central →
Full text: free to read — PubMed Central lists this copy as free to read: the link above (checked 10 Oct 2026).
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
APA 7th
Shen, J., Chen, H., Gong, Y., Huang, Y., Wu, M., Gu, Y., et al. (2026). Association between plant-based diets and incident dementia: results from prospective cohort studies and a meta-analysis. The journal of prevention of Alzheimer's disease. https://doi.org/10.1016/j.tjpad.2025.100457
Vancouver
Shen J, Chen H, Gong Y, Huang Y, Wu M, Gu Y, et al. Association between plant-based diets and incident dementia: results from prospective cohort studies and a meta-analysis. The journal of prevention of Alzheimer's disease. 2026. doi:10.1016/j.tjpad.2025.100457. PMID: 41564649.
BibTeX
@article{shen2026-41564649,
author = {Shen, Jie and Chen, Hui and Gong, Yiying and Huang, Yuhui and Wu, Minyu and Gu, Yuxuan and Wang, Tian and Fontana, Luigi and others},
title = {{Association between plant-based diets and incident dementia: results from prospective cohort studies and a meta-analysis}},
journal = {The journal of prevention of Alzheimer's disease},
year = {2026},
doi = {10.1016/j.tjpad.2025.100457},
pmid = {41564649},
url = {https://doi.org/10.1016/j.tjpad.2025.100457}
}
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