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Reference: Petersson, S.D. and E. Philippou, Mediterranean Diet, Cognitive Function, and Dementia: A Systematic Review of the Evidence. Adv Nutr, 2016. 7(5): p. 889-904.
One-sentence summary: A Mediterranean diet reduced the risk of cognitive impairment and dementia, and was associated with improved cognitive functioning.
Study type: A systematic literature review of 5 RCTs and 27 observational studies.
Diet: Adherence to the Mediterranean diet or a Mediterranean diet intervention. Adherence to a Mediterranean diet was defined through scores that estimated the conformity of the dietary pattern of the studies’ population with the Mediterranean dietary pattern.
Outcomes measured: Cognitive function or cognitive decline (e.g. dementia).
Population: Most of the studies (n = 26) included participants aged >60 years, and nineteen of the 32 studies included only women. Studies were from the United States (16 studies), Europe (11 studies), Australia (4 studies) and China (1 study).
Quality assessment of studies was undertaken using custom checklists derived from existing widely used questionnaires that included items related to population, recruitment, assessment of exposure and outcome, confounding, and statistical analyses. The overall quality of the studies was rated as average.
The bottom line:
A Mediterranean diet may improve cognitive performance and be protective for cognitive impairment and dementia; although the majority of the evidence is observational without adjusting for confounders. More RCTs and large epidemiological studies adjusted for confounders are needed in order to strengthen the empirical evidence for the role of the Mediterranean Diet in cognitive function, as well as the roles of the individual dietary components.
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