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Study links omega-3 supplements with increased risk of cognitive decline

The study authors stress that the findings are not definitive

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Mark Huffman
Reporter

Mark Huffman has covered consumer issues since 2004, with a special focus on protecting and empowering older adults. A former news correspondent for the Associated Press Radio Network, Westwood One, and ConsumerAffairs, Mark brings decades of journalistic experience to RetirementLiving.com. He is passionate about giving consumers a voice and helping them make informed decisions. Mark has also created educational content, including Senior Scam Alert, a video resource designed to help seniors recognize and avoid fraud. He holds a B.A. from the University of Kentucky and lives with his family in Richmond, Virginia.
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Key Insights

  • A new longitudinal study in the Journal of Prevention of Alzheimer’s Disease found that people taking omega-3 supplements showed faster cognitive decline than non-users across multiple standard tests of memory and thinking.
  • The decline was observed in measures such as MMSE, ADAS-Cog13, and CDR-SB, indicating worsening global cognition, memory, and functional abilities over time.
  • Researchers concluded that omega-3 supplementation may be linked to accelerated brain metabolic dysfunction (reduced glucose use in key brain regions) rather than classic Alzheimer’s markers like amyloid or tau.

Omega-3 supplements may have health benefits, but a new study suggests they may also increase the risk of cognitive decline in older adults.

The study analyzed data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI), following older adults over time to track supplement use, cognitive performance, and brain imaging changes. 

Contrary to the long-held belief that omega-3s protect the brain, the researchers found a consistent association between supplement use and more rapid cognitive deterioration. Importantly, this relationship was not explained by traditional Alzheimer’s pathology (such as amyloid plaques or tau tangles), suggesting a different biological mechanism may be involved. 

Instead, brain scans pointed to reduced metabolic activity (FDG hypometabolism) in regions vulnerable to Alzheimer’s disease as a key pathway linking omega-3 supplementation to decline.

Findings are not definitive

The authors emphasize that these findings do not necessarily prove omega-3 supplements cause cognitive decline, but they do challenge assumptions about their universal benefit and highlight the need for more targeted research on who may benefit — or potentially be harmed — by supplementation.

Before stopping or starting omega-3 supplements, it may be wise to discuss the matter with your healthcare provider.