Gregory, S, Pullen, H, Ritchie, C W, Shannon, O M, Stevenson, E J & Muniz-terrera, G 2022, ' Mediterranean diet and structural neuroimaging biomarkers of Alzheimer's and cerebrovascular disease : A systematic review ', Experimental gerontology, vol. 172, 112065, pp. 112065 . https://doi.org/10.1016/j.exger.2022.112065Test
Background: Adherence to the MedDiet has been associated with better cognitive performance, lower incidence of dementia, stroke and lower Alzheimer’s disease (AD) biomarker burden. The aim of this study was to evaluate the evidence base for the MedDiet in relation to hippocampal volume and white matter hyperintensity volume (WMHV). Methods: For the systematic review we searched for studies reporting on MedDiet and hippocampal volume or WMHV in MedLine, EMBASE, CINAHL and PsycInfo. We included studies with adult participants in any setting, time or language. Searches were initially carried out on 21 st July 2021 with final searches run on 19 th August 2021. Papers were screened independently by two authors (SG and HP) against eligibility criteria. Data on participant demographics, MedDiet calculation and adherence, hippocampal volume and/or WMHV was extracted by one author (SG) and checked by a second author (SG). Data was narratively synthesised. Findings: Of an initial 111 papers identified, five papers, enrolling 2566 participants, were eligible for inclusion in the review. The mean age of participants in studies ranged from 68.8 years to 80.3 years and participants were healthy volunteers, had subjective cognitive decline, or dementia. All studies included in the review were cross-sectional or cohort studies. Three studies reported on hippocampal volume, with inconclusive or no associations seen with MedDiet adherence. One study found a significant association between higher MedDiet adherence and lower WMHV, while two other studies found no significant associations. Interpretation: Overall these results highlight a gap in our knowledge about the associations between MedDiet and AD and cerebrovascular related structural neuroimaging findings. Future research is needed to increase the frequency of dietary assessments, alternative imaging outcomes and data from low and middle income countries. Registration Details: PROSPERO Registration: CRD42021269620 Funding Information: This systematic review was funded by the MRC (MRC UK Nutrition Research Partnership (NRP) Collaboration Award (MR/T001852/1). Declaration of Interests: All authors have completed the ICMJE uniform disclosure form at http://www.icmje.org/disclosure-of-interestTest/. SG and OS receive support from the MRC for this work. OS has received a research grant from the Newcastle NIHR BRC; CWR has received consultancy fees from Biogen, Eisai, MSD, Actinogen, Roche, and Eli Lilly, as well as payment or honoraria from Roche and Eisai; no other relationships or activities that could appear to have influenced the submitted work.
