Study Design
- Cohort: 217,000+ adults from the UK Biobank, aged 40–64, dementia-free at baseline
- Follow-up: Average 8.3 years
- Method: Measured blood omega-3 levels (objective biomarker, not self-reported diet)
- Outcome: 325 cases of early-onset dementia (diagnosed before age 65)
Key Findings
- Participants in the highest omega-3 quintiles had 35–40% lower risk of early-onset dementia
- The association held even after adjusting for APOE-ε4 genetic risk, lifestyle, and cardiometabolic factors
- Both DHA and non-DHA omega-3 showed significant inverse associations, with non-DHA omega-3 being slightly stronger
- This suggests omega-3 benefits for the brain aren't limited to just DHA (EPA and others matter too)
Why It Matters
- First large-scale study linking objectively measured omega-3 blood levels to lower early-onset dementia risk
- Uses blood biomarkers instead of dietary questionnaires (much more reliable)
- Suggests omega-3 may be protective even against genetically-driven dementia risk
Bottom Line
Higher omega-3 in your blood = meaningfully lower risk of developing dementia before 65, regardless of your genetics.