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Mediterranean diet and cognitive function: From methodology to mechanisms of action
Siervo M, Shannon OM, Llewellyn DJ, Stephan BC, Fontana L.. Free radical biology & medicine, 2021-09-22
Topic: Risk, prevention and care in population studies
The traditional Mediterranean diet (MedDiet), rich in minimally processed plant foods and fish, has been widely recognized to be one of the healthiest diets. Data from multiple randomized clinical trials have demonstrated its powerful effect against oxidative stress, inflammation and the development and progression of cardiovascular disease, type 2 diabetes, and other metabolic conditions that play a crucial role in the pathogenesis of neurodegenerative diseases. The protecting effects of the MedDiet against cognitive decline have been investigated in several observational and experimental studies. Data from observational studies suggest that the MedDiet may represent an effective dietary strategy for the early prevention of dementia, although these findings require further substantiation in clinical trials which have so far produced inconclusive results. Moreover, as we discuss in this review, accumulating data emphasizes the importance of: 1) maintaining an optimal nutritional and metabolic status for the promotion of healthy cognitive aging, and 2) implementing cognition-sparing dietary and lifestyle interventions during early time-sensitive windows before the pathological cascades turn into an irreversible state. In summary, components of the MedDiet pattern, such as essential fatty acids, polyphenols and vitamins, have been associated with reduced oxidative stress and the current evidence from observational studies seems to assign to the MedDiet a beneficial role in promoting brain health; however, results from clinical trials have been inconsistent. While we advocate for longitudinal analyses and for larger and longer clinical trials to be conducted, we assert our interim support to the use of the MedDiet as a protective dietary intervention for cognitive function based on its proven cardiovascular and metabolic benefits.
Key findings
- Data from multiple randomized clinical trials have demonstrated its powerful effect against oxidative stress, inflammation and the development and progression of cardiovascular disease, type 2 diabetes, and other metabolic conditions that play a crucial role in the pathogenesis of neurodegenerative diseases.
- Data from observational studies suggest that the MedDiet may represent an effective dietary strategy for the early prevention of dementia, although these findings require further substantiation in clinical trials which have so far produced inconclusive results.
- In summary, components of the MedDiet pattern, such as essential fatty acids, polyphenols and vitamins, have been associated with reduced oxidative stress and the current evidence from observational studies seems to assign to the MedDiet a beneficial role in promoting brain health; however, results from clinical trials have been inconsistent.
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Study details
- Study designlongitudinal study
- Evidence strengthHigh
How this study scored 59/100
Published in a peer-reviewed journal, and it is a longitudinal study following the same people over time. Scored zero for sample size, effect reported, studied in people and randomised / blinded because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record and multi-centre collaboration, so those were left out: it earned 34 of the 58 points we could judge it on, which is 59 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Free radical biology & medicine) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 7 / 12 | A longitudinal study following the same people over time |
| Strength of evidence | 5 / 5 | Rated “high” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 3 / 5 | 2021 — within 6 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 34562607) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 34 / 58 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 34 of the 58 points we could judge it on is 59 out of 100. |
| Total | 59 / 100 | — |
What each of these 20 components measures, and what this score is not →
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APA 7th
Siervo, M., Shannon, O. M., Llewellyn, D. J., Stephan, B. C., & Fontana, L. (2021). Mediterranean diet and cognitive function: From methodology to mechanisms of action. Free radical biology & medicine. https://doi.org/10.1016/j.freeradbiomed.2021.09.018
Vancouver
Siervo M, Shannon OM, Llewellyn DJ, Stephan BC, Fontana L. Mediterranean diet and cognitive function: From methodology to mechanisms of action. Free radical biology & medicine. 2021. doi:10.1016/j.freeradbiomed.2021.09.018. PMID: 34562607.
BibTeX
@article{siervo2021-34562607,
author = {Siervo, M. and Shannon, O. M. and Llewellyn, D. J. and Stephan, B. C. and Fontana, L.},
title = {{Mediterranean diet and cognitive function: From methodology to mechanisms of action}},
journal = {Free radical biology \& medicine},
year = {2021},
doi = {10.1016/j.freeradbiomed.2021.09.018},
pmid = {34562607},
url = {https://doi.org/10.1016/j.freeradbiomed.2021.09.018}
}