Unexpected side effect of omega-3 - supplement may harm the brain

American researchers have discovered that one of the omega-3 fatty acids, EPA, may not help brain recovery after traumatic brain injury, but rather hinder this process. Experiments on mice showed that EPA worsens results in memory and learning tests and interferes with the restoration of brain blood vessels. Scientists emphasize that the findings are based on laboratory data and further research in humans is needed.

American researchers have obtained data that challenge the conventional wisdom about the benefits of fish oil supplements. In a 2026 study, scientists found that eicosapentaenoic acid (EPA), one of the omega-3 fatty acids, may not help the damaged brain recover, but rather hinder this process after traumatic brain injury. Experiments on mice with mild head injuries showed that animals fed a diet high in EPA performed worse on tests of spatial memory and learning ability. Further investigation revealed that EPA interfered with the restoration of brain blood vessels by altering the metabolic activity of vascular cells, causing energy resources to be redistributed and poorly utilized for recovery processes. Scientists separately examined the effect of another omega-3 acid, DHA, which did not show such negative effects. Meanwhile, EPA accumulated in the damaged brain tissues of the animals, and researchers link its impact to impaired vascular function and subsequent accumulation of tau proteins associated with degenerative processes. The researchers also analyzed brain tissue from people with chronic traumatic encephalopathy and found similar abnormalities. However, the authors do not claim that omega-3 supplements are harmful to everyone and emphasize that further research involving humans is needed.