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Mediterranean Diet and Age-Related Cognitive Decline: A Randomized Clinical Trial
Valls-Pedret C, Sala-Vila A, Serra-Mir M, Corella D, de la Torre R, Martínez-González MÁ, et al.. JAMA Internal Medicine, 2015
Topic: Risk, prevention and care in population studies
Epidemiologic studies suggest that a Mediterranean diet, an antioxidant-rich cardioprotective dietary pattern, delays cognitive decline, but clinical trial evidence is lacking. Objective To investigate whether a Mediterranean diet supplemented with antioxidant-rich foods influences cognitive function compared with a control diet. Results Follow-up cognitive tests were available in 334 participants after intervention (median, 4.1 years). In multivariate analyses adjusted for confounders, participants allocated to a Mediterranean diet plus olive oil scored better on the RAVLT (P = .049) and Color Trail Test part 2 (P = .04) compared with controls; no between-group differences were observed for the other cognitive tests. All cognitive composites significantly (P Conclusions and relevance In an older population, a Mediterranean diet supplemented with olive oil or nuts is associated with improved cognitive function.
Key findings
- Epidemiologic studies suggest that a Mediterranean diet, an antioxidant-rich cardioprotective dietary pattern, delays cognitive decline, but clinical trial evidence is lacking.
- Objective To investigate whether a Mediterranean diet supplemented with antioxidant-rich foods influences cognitive function compared with a control diet.
- Results Follow-up cognitive tests were available in 334 participants after intervention (median, 4.1 years).
- In multivariate analyses adjusted for confounders, participants allocated to a Mediterranean diet plus olive oil scored better on the RAVLT (P = .049) and Color Trail Test part 2 (P = .04) compared with controls; no between-group differences were observed for the other cognitive tests.
- All cognitive composites significantly (P Conclusions and relevance In an older population, a Mediterranean diet supplemented with olive oil or nuts is associated with improved cognitive function.
Why it matters
In this randomized trial of an older population, 334 participants had follow-up cognitive tests after a median of 4.1 years. The group assigned to a Mediterranean diet plus olive oil scored better than the control-diet group on two tests (RAVLT, P = .049; Color Trail Test part 2, P = .04), with no differences on the other tests. The study measured test scores, not dementia, so it does not show that this diet prevents or treats Alzheimer's disease.
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Study details
- Study designRCT
- Participants447
- Effect sizeGlobal cognition composite: +0.05 (95% CI -0.11 to 0.21) olive-oil arm vs -0.38 (-0.57 to -0.18) control; P=0.005
- Evidence strengthModerate
Limitations
Only 334 of 447 participants had follow-up testing; single city; a 2018 published correction addressed randomisation irregularities in the parent PREDIMED trial, so results should be read alongside that erratum.
How this study scored 82/100
Published in a leading specialty journal, and it is a randomised controlled trial. We have no data on free to read, so that was left out: it earned 80 of the 98 points we could judge it on, which is 82 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (JAMA Internal Medicine) |
| Journal's citation record | 3 / 4 | JAMA Internal Medicine: journal h-index 258 (OpenAlex, 2026-10-29) |
| Study design | 11 / 12 | A randomised controlled trial |
| 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 | 1 / 5 | 2015 — within 20 year(s) of the newest study here |
| Sample size | 2 / 4 | 447 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 | 1 / 2 | Randomised (as stated in the record) |
| Times cited | 6 / 7 | Cited 948 times (OpenAlex, 2026-10-10) |
| Citations per year | 5 / 5 | 72.9 citations a year over 13 year(s) since 2015 |
| Impact for its field and year | 6 / 6 | Cited 71.0× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 4 / 6 | Cited by 44 other studies in this library |
| Still being cited | 4 / 4 | Cited 274 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 4 / 4 | Last-listed author Emilio Ros: h-index 122 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | Universitat de València: institution h-index 846 (OpenAlex) |
| Multi-centre collaboration | 2 / 3 | OpenAlex lists 9 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 25961184) |
| Free to read | — / 2 | Access not recorded — left out of this score |
| Points | 80 / 98 | Scored on 19 of 20 parts. We have no data for the rest, so they are left out: 80 of the 98 points we could judge it on is 82 out of 100. |
| Total | 82 / 100 | — |
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Read the original
- DOI: 10.1001/jamainternmed.2015.1668
- PubMed: 25961184
- Original source →
- Free full text: hdl.handle.net →
Full text: free to read — Unpaywall 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
Valls-Pedret, C., Sala-Vila, A., Serra-Mir, M., Corella, D., de la Torre, R., MÁ, M.-G., et al. (2015). Mediterranean Diet and Age-Related Cognitive Decline: A Randomized Clinical Trial. JAMA Internal Medicine. https://doi.org/10.1001/jamainternmed.2015.1668
Vancouver
Valls-Pedret C, Sala-Vila A, Serra-Mir M, Corella D, de la Torre R, MÁ M.-G, et al. Mediterranean Diet and Age-Related Cognitive Decline: A Randomized Clinical Trial. JAMA Internal Medicine. 2015. doi:10.1001/jamainternmed.2015.1668. PMID: 25961184.
BibTeX
@article{vallspedret2015-25961184,
author = {Valls-Pedret, C. and Sala-Vila, A. and Serra-Mir, M. and Corella, D. and de la Torre, R. and MÁ, Martínez-González and others},
title = {{Mediterranean Diet and Age-Related Cognitive Decline: A Randomized Clinical Trial}},
journal = {JAMA Internal Medicine},
year = {2015},
doi = {10.1001/jamainternmed.2015.1668},
pmid = {25961184},
url = {https://doi.org/10.1001/jamainternmed.2015.1668}
}
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