Abstract
CONTEXT: Diet plays a critical role in cognitive integrity and decline in older adults. However, little is known about the relationship between diet and cognitive integrity in middle age. OBJECTIVE: To investigate the relationship between dietary patterns in healthy middle-aged adults and neurocognition both in middle age and later in life. DATA SOURCES: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, the following electronic databases were searched: Web of Science, Scopus, PubMed, and PsychInfo. DATA EXTRACTION: Data from eligible articles was extracted by 2 reviewers. DATA ANALYSIS: Articles included in the systematic review were synthesized (based on the synthesis without meta-analysis reporting guidelines) and assessed for quality (using the Joanna Briggs Institute checklist for randomized controlled trials, cohort studies, and cross-sectional studies) by 2 reviewers. RESULTS: Of 1558 studies identified, 34 met the eligibility criteria for inclusion. These comprised 9 cross-sectional studies, 23 longitudinal or prospective cohort studies, and 2 randomized controlled trials. Findings were mixed, with some studies reporting a significant positive relationship between adherence to various "healthy" dietary patterns and neurocognition, but others reporting no such relationship. CONCLUSION: This systematic review demonstrated that adherence to the Mediterranean diet and other healthy dietary patterns in middle age can protect neurocognition later in life. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42020153179.