Dietary patterns across the continuum of age-related cognitive decline: a scoping review

Cognitive impairment (CI) represents a progressive syndrome along the continuum from subjective cognitive decline (SCD) to dementia, with no curative treatment available. Dietary patterns, as a modifiable factor, have been linked to a slower rate of cognitive deterioration. This study aims to systematically map the effects of different dietary patterns on the progression of CI and to inform precision nutritional care for older adults. This scoping review was conducted following PRISMA-ScR guidelines and the Joanna Briggs Institute (JBI) framework. A systematic search was performed in PubMed, Cochrane Library, Web of Science, Embase, Scopus, SinoMed, VIP, and Wanfang from inception to January 27, 2026. Eligibility criteria were defined using the PCC (Population, Concept, Context) framework. Studies published in Chinese or English were included. Two reviewers independently screened titles, abstracts, and full texts. Data were synthesized narratively and mapped in tables and figures. 16 studies were included (6 randomized controlled trials, 9 observational studies, and 1 pilot study). Mediterranean diet (MD), the Dietary Approaches to Stop Hypertension diet (DASH), the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet, the ketogenic diet (KD) were the main patterns. The intervention duration ranged from 6 weeks to one year. These dietary patterns were associated with better global and domain-specific cognition, a low risk of Alzheimer’s disease (AD), and a slower rate of cognitive decline. Eight biological pathways were identified, encompassing multiple interconnected mechanisms. Healthy dietary patterns exert protective effects across the cognitive continuum. MIND and MD were the most frequently investigated patterns and showed consistent associations with more favorable cognitive outcomes. Clinical practice should integrate early nutritional assessment, culturally adapted dietary interventions, and long-term adherence management to slow cognitive decline. Current studies exhibit considerable heterogeneity in outcome measures, intervention durations, and study populations, leading to inconsistent evidence. Future research should include large-scale, long-term, and standardized clinical studies to develop culturally appropriate and precise dietary intervention strategies. Open Science Framework https://doi.org/10.17605/OSF.IO/J7FPV .