Mediterranean Diet, Alzheimer Disease Biomarkers, and Brain Atrophy in Old Age

Abstract

Objective:To determine if following a Mediterranean-like diet (MeDi) relates to cognitive functions and in vivo biomarkers for Alzheimer’s disease (AD), we analyzed cross-sectional data from the German Longitudinal Cognitive Impairment and Dementia StudyMethod:The sample (n=512, mean age: 69.5±5.9 years) included 169 cognitively normal participants and subjects at higher AD risk (53 AD relatives, 209 SCD and 81 MCI). We defined MeDi adherence based on the Food Frequency Questionnaire. Brain volume outcomes were generated via voxel-based morphometry on T1-MRI and cognitive performance with an extensive neuropsychological battery. AD-related biomarkers (Aβ42/40 ratio, pTau181) in cerebrospinal fluid were assessed in n=226 individuals. We analyzed the associations between MeDi and the outcomes with linear regression models controlling for several covariates. Additionally, we applied hypothesis-driven mediation and moderation analysis.Results:Higher MeDi adherence related to larger mediotemporal gray matter volume (p<0.05 FWE corrected), better memory (β±SE = 0.03 ± 0.02; p=0.038), and less amyloid (Aβ42/40 ratio, β±SE = 0.003 ± 0.001; p=0.008) and pTau181 pathology (β±SE = -1.96±0.68; p=0.004). Mediotemporal volume mediated the association between MeDi and memory (40% indirect mediation). Finally, MeDi favorably moderated the associations between Aβ42/40 ratio, pTau181 and mediotemporal atrophy. Results were consistent correcting for ApoE-ε4 status.Conclusion:Our findings corroborate the view of MeDi as a protective factor against memory decline and mediotemporal atrophy. Importantly, they suggest that these associations might be explained by a decrease of amyloidosis and tau-pathology. Longitudinal and dietary intervention studies should further examine this conjecture and its treatment implications.

US Older Adults That Consume Avocado or Guacamole Have Better Cognition Than Non-consumers: National Health and Nutrition Examination Survey 2011–2014

“…In a cross-sectional analysis of the National Health and Nutrition Examination Survey (NHANES) survey (2011-2014), Taylor et al found that greater Mediterranean Diet adherence was associated with better cognitive performance among individuals aged 60 years and older (6). Similarly, the German Longitudinal Cognitive Impairment and Dementia Study found that those with greater adherence to the Mediterranean Diet had better memory in older adults (7). Although avocados are not part of a traditional Mediterranean diet, consumption is dramatically increasing worldwide, and their nutrient profile aligns strikingly well with the Mediterranean dietary pattern.…”

Alzheimer’s Disease, Mild Cognitive Impairment and Mediterranean Diet. A Systematic Review and Dose-Response Meta-Analysis

“…According to nationality, fourteen studies [ 1 , 3 , 7 , 8 , 10 , 13 , 17 , 20 , 27 , 33 , 35 , 36 , 38 ] included American participants, four studies [ 9 , 15 , 31 , 32 ] included Australian participants, one study [ 34 ] shows results of Swedish individuals, one study [ 11 ] is based on Brazilian results, other one the participants were German [ 30 ] and only one study was performed in France [ 37 ].…”

“…Eight longitudinal studies [ 1 , 13 , 14 , 16 , 27 , 34 , 37 , 38 ], eleven cross-sectional articles [ 3 , 8 , 10 , 11 , 12 , 17 , 30 , 31 , 32 , 33 , 35 ] and one case-control study nested in a cohort [ 17 ] were included. Also, two studies [ 7 , 36 ] that analyzed its main associations cross-sectional and longitudinally were reviewed.…”

“…Among the studies included, seven of them [ 1 , 10 , 11 , 16 , 20 , 30 , 37 ] analyzed associations between MD adherence and neuropsychological tests (NPT). Significant results were found in four of them.…”

“…One study [ 10 ] showed that higher MD adherence was related with better learning and memory performance in non-demented subjects. Other study showed that higher MD adherence was related with better memory [ 30 ]. Another one [ 11 ] demonstrated association between higher adherence MD and higher Mini-Mental State Examination (MMSE) scores in Cognitively Normal (CN).…”