Interactions Between Omega-3 Fatty Acids and Genetic Variants in Contributing to Cognitive Decline and Cardiovascular Disease Risk in Older Adults: A Systematic Review.
Level 3 - non-randomized controlled study
Systematic review of heterogeneous observational studies without meta-analysis
PubMed 41818679 · doi:10.1093/nutrit/nuag019
What was done
Systematic review (PROSPERO CRD42024623183) searching Embase, Medline, Scopus, and Web of Science through December 10, 2024. Two independent reviewers screened records and assessed risk of bias to examine whether genetic variants modify the association between fish intake or omega-3 fatty acids and cognitive decline or cardiovascular disease in community-dwelling adults aged 65 years and older.
What was found
Of 2349 records identified, 15 studies met inclusion criteria. Meta-analysis was precluded by substantial heterogeneity. Studies reported conflicting findings for dementia, Alzheimer disease, and cardiovascular disease outcomes; however, higher omega-3 biomarker levels or fish intake appeared associated with slower cognitive decline in APOE-ε4 carriers. The abstract reports no numerical effect sizes or risk estimates.
Why it matters
It highlights that genetic status (APOE-ε4) may influence the cognitive response to omega-3 intake, but confirms the broader evidence base for dementia and cardiovascular disease outcomes remains inconsistent.
Limits
The abstract provides no quantitative effect estimates or sample sizes across included studies. Substantial heterogeneity prevented meta-analysis, and evidence for major clinical endpoints is small and conflicting.