Trial of 365 Adults Finds Omega-3 Supplements Fail to Improve Cognition After 24 Months
Updated
Updated · CNN · Jun 18
Trial of 365 Adults Finds Omega-3 Supplements Fail to Improve Cognition After 24 Months
1 articles · Updated · CNN · Jun 18
Summary
A randomized, double-blind trial of 365 adults aged 55 to 80 found high-dose omega-3 supplements did not improve memory, cognition or hippocampus size versus placebo over 24 months.
The null result held even though the treatment group’s red-blood-cell omega-3 levels rose from 4.9% to 11% and cerebrospinal-fluid DHA increased 17% after six months.
Nearly 50% of participants carried at least one APOE4 variant and all had very low omega-3 levels plus dementia risk factors such as obesity, inactivity, high blood pressure or high cholesterol; they still showed no cognitive benefit.
Lead author Hussein Yassine said supplements are a poor standalone tool for dementia prevention, pointing instead to exercise, sleep, stress reduction, plant-based eating and omega-3-rich whole foods such as fatty fish, nuts and seeds.
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Omega-3 Supplements Alone Don’t Prevent Cognitive Decline: 2026 Study Underscores Importance of Holistic Brain Health
Overview
A major clinical trial published in June 2026 found that high-dose omega-3 supplements, despite being essential nutrients that help form brain cell connections vital for cognition, did not improve memory or prevent brain cell loss in older adults at risk for dementia. Even though participants’ omega-3 levels increased, there was no cognitive benefit compared to placebo. This challenges the belief that taking fish oil supplements alone can protect brain health, highlighting that while omega-3s are important, their benefits are best realized as part of a healthy lifestyle rather than as a standalone solution.