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Association between Mediterranean diet and dementia and Alzheimer disease: a systematic review with meta-analysis
Nucci D, Sommariva A, Degoni LM, Gallo G, Mancarella M, Natarelli F, et al.. Aging Clinical and Experimental Research, 2024-03-22
Topic: Amyloid, tau and blood-test diagnosis
Background Dementia affects 5-8% of the population aged over 65 years (~50 million worldwide). Several factors are associated with increased risk, including diet. The Mediterranean diet (MedDiet) has shown potential protective effects against several chronic diseases. Aims This systematic review with meta-analysis aim was to assess the association between adherence to the MedDiet and the risk of dementia in the elderly. Methods PRISMA-2020 guidelines were followed. PubMed/MEDLINE and Scopus were searched on 17 July 2023. The Newcastle-Ottawa Scale tool was used to assess the risk of bias. The protocol was pre-registered in PROSPERO (registration number: CRD 42023444368). Heterogeneity was assessed using the I 2 test. Publication bias was assessed by visual inspection of the funnel plot and by Egger's regression asymmetry test. The final effect size was reported as OR or HR, depending on the study design of the included studies. Results Out of 682 records, 21 were included in the analysis. The pooled OR was 0.89 (95% CI = 0.84-0.94) based on 65,955 participants (I 2 = 69.94). When only cohort studies were included, HR was 0.84 (95% CI = 0.76-0.94) based on 55,205 participants (I 2 = 89.70). When only Alzheimer Disease was considered OR was 0.73 (95% CI = 0.62-0.85) based on 38,292 participants (I 2 = 63.85). Discussion Despite the relatively low risk reduction associated with higher adherence to MedDiet among elderly, it should be considered that this population is the most affected. Conclusions Adherence to MedDiet could be an effective non-pharmacological measure to reduce the burden of dementia, even among elderly.
Key findings
- Several factors are associated with increased risk, including diet.
- Results Out of 682 records, 21 were included in the analysis.
- Discussion Despite the relatively low risk reduction associated with higher adherence to MedDiet among elderly, it should be considered that this population is the most affected.
Why it matters
Pooling 21 observational studies (65,955 older adults), this pre-registered meta-analysis found that closer adherence to a Mediterranean diet was linked to modestly lower odds of dementia (OR 0.89) and somewhat lower odds of Alzheimer disease (OR 0.73). The authors describe the risk reduction as "relatively low", and results varied considerably between studies. Because the included studies were observational, this shows an association, not that the diet prevents dementia.
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Study details
- Study designmeta-analysis
- Participants65,955
- Effect sizePooled OR 0.89 (95% CI 0.84-0.94) for dementia; cohort HR 0.84 (0.76-0.94); Alzheimer's OR 0.73 (0.62-0.85)
- Evidence strengthModerate
Limitations
High heterogeneity (I2 70-90%); mix of odds and hazard ratios; observational designs with varied diet scores.
How this study scored 73/100
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 72 of the 98 points we could judge it on, which is 73 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Aging Clinical and Experimental Research) |
| Journal's citation record | 1 / 4 | Aging Clinical and Experimental Research: journal h-index 125 (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 | 4 / 5 | 2024 — within 3 year(s) of the newest study here |
| Sample size | 4 / 4 | 65,955 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 | 5 / 7 | Cited 100 times (OpenAlex, 2026-10-10) |
| Citations per year | 4 / 5 | 25.0 citations a year over 4 year(s) since 2024 |
| Impact for its field and year | 4 / 6 | Cited 12.5× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 3 / 6 | Cited by 14 other studies in this library |
| Still being cited | 3 / 4 | Cited 100 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Vincenza Gianfredi: h-index 39 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | University of Milan: institution h-index 1,023 (OpenAlex) |
| Multi-centre collaboration | 1 / 3 | OpenAlex lists 3 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 38519775) |
| Free to read | — / 2 | Access not recorded — left out of this score |
| Points | 72 / 98 | Scored on 19 of 20 parts. We have no data for the rest, so they are left out: 72 of the 98 points we could judge it on is 73 out of 100. |
| Total | 73 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
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
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APA 7th
Nucci, D., Sommariva, A., Degoni, L. M., Gallo, G., Mancarella, M., Natarelli, F., et al. (2024). Association between Mediterranean diet and dementia and Alzheimer disease: a systematic review with meta-analysis. Aging Clinical and Experimental Research. https://doi.org/10.1007/s40520-024-02718-6
Vancouver
Nucci D, Sommariva A, Degoni LM, Gallo G, Mancarella M, Natarelli F, et al. Association between Mediterranean diet and dementia and Alzheimer disease: a systematic review with meta-analysis. Aging Clinical and Experimental Research. 2024. doi:10.1007/s40520-024-02718-6. PMID: 38519775.
BibTeX
@article{nucci2024-38519775,
author = {Nucci, D. and Sommariva, A. and Degoni, L. M. and Gallo, G. and Mancarella, M. and Natarelli, F. and others},
title = {{Association between Mediterranean diet and dementia and Alzheimer disease: a systematic review with meta-analysis}},
journal = {Aging Clinical and Experimental Research},
year = {2024},
doi = {10.1007/s40520-024-02718-6},
pmid = {38519775},
url = {https://doi.org/10.1007/s40520-024-02718-6}
}
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