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Western Mediterranean diet predicts 9-year changes in episodic memory in an adult lifespan sample of Americans
Kelly Rose Burdett Parker, Ryan P. McGrath, Yeong S. Rhee, Jeremy M. Hamm. Journal of Alzheimer s Disease, 2025-03-17
Topic: Risk, prevention and care in population studies
Background The Mediterranean Diet (MD) is well-studied for slowing cognitive declines. Few studies have examined how a Western MD (wMD) may impact cognitive function. Objective This study examined whether a wMD predicted less cognitive decline over 9 years in a national sample of American adults. The measures were episodic memory (EM) and executive functioning (EF) at baseline and 9 years follow-up. Methods This is a secondary analysis of the Midlife in the United States Study (MIDUS), using a longitudinal cohort design with cross-sectional dietary data. Participants in this study had data from Waves 2 and 3 of MIDUS ( n = 833, 46 ± 12 years; 45% male). Regression analyses tested whether wMD adherence predicted 9-year changes in EM and EF. Moderator analyses determined whether the relationship between wMD, EM, and EF differed across sociodemographic characteristics. Results wMD score at Wave 2 predicted attenuated declines in EM 9 years later (β = 0.06, p = 0.04). The association between wMD and EM was not moderated by age, sex, race, education, or income and thus is consistent across sociodemographic subpopulations. wMD did not predict EF (fully adjusted wMD β = 0.00, p = 0.86). Contextualized effect sizes showed that individuals who strongly adhered to the wMD (+1 SD) experienced ∼50–60% less decline in 9-year EM when compared to those with average adherence. Conclusions A wMD was related to slowed EM declines across sociodemographic populations in a national U.S. sample. Education is needed about healthful dietary habits, including increased fruit and vegetable intake.
Key findings
- Results wMD score at Wave 2 predicted attenuated declines in EM 9 years later (β = 0.06, p = 0.04).
- Contextualized effect sizes showed that individuals who strongly adhered to the wMD (+1 SD) experienced ∼50–60% less decline in 9-year EM when compared to those with average adherence.
Why it matters
In this 9-year study of 833 American adults, stronger adherence to a Western Mediterranean diet predicted less decline in episodic memory but did not predict executive functioning. This suggests that this dietary pattern may help slow memory decline, though it did not affect all cognitive abilities.
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Study details
- Study designcross-sectional
- Participants833
- Evidence strengthModerate
How this study scored 46/100
Published in a peer-reviewed journal, and it is a snapshot of people at one point in time. Scored zero for effect reported and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Journal of Alzheimer s Disease) |
| Journal's citation record | 2 / 4 | Journal of Alzheimer s Disease: journal h-index 218 (OpenAlex, 2026-10-29) |
| Study design | 4 / 12 | A snapshot of people at one point in time |
| 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 | 2025 — within 3 year(s) of the newest study here |
| Sample size | 2 / 4 | 833 participants |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 1 / 7 | Cited 3 times (OpenAlex, 2026-10-10) |
| Citations per year | 1 / 5 | 1.0 citations a year over 3 year(s) since 2025 |
| Impact for its field and year | 2 / 6 | Cited 2.5× 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 3 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Jeremy M. Hamm: h-index 22 (OpenAlex, whole career) |
| Institution's track record | 0 / 3 | North Dakota State University: institution h-index 351 (OpenAlex) |
| Multi-centre collaboration | 0 / 3 | OpenAlex lists 1 institution(s) in 1 country — scores zero (affiliation lists can be incomplete) |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 40091565) |
| Free to read | 2 / 2 | Free to read |
| Total | 46 / 100 | — |
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Read the original
- DOI: 10.1177/13872877251320861
- PubMed: 40091565
- Original source →
- Free full text: Journal of Alzheimer s Disease →
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
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. Check the citation against the original before you use it.
APA 7th
Parker, K. R. B., McGrath, R. P., Rhee, Y. S., & Hamm, J. M. (2025). Western Mediterranean diet predicts 9-year changes in episodic memory in an adult lifespan sample of Americans. Journal of Alzheimer s Disease. https://doi.org/10.1177/13872877251320861
Vancouver
Parker KRB, McGrath RP, Rhee YS, Hamm JM. Western Mediterranean diet predicts 9-year changes in episodic memory in an adult lifespan sample of Americans. Journal of Alzheimer s Disease. 2025. doi:10.1177/13872877251320861. PMID: 40091565.
BibTeX
@article{parker2025-40091565,
author = {Parker, Kelly Rose Burdett and McGrath, Ryan P. and Rhee, Yeong S. and Hamm, Jeremy M.},
title = {{Western Mediterranean diet predicts 9-year changes in episodic memory in an adult lifespan sample of Americans}},
journal = {Journal of Alzheimer s Disease},
year = {2025},
doi = {10.1177/13872877251320861},
pmid = {40091565},
url = {https://doi.org/10.1177/13872877251320861}
}
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