Onder Albayram Fish Oil Raises Alarm as Study Links EPA Supplements to Tau Buildup Following Repeated Head Injuries

A new scientific study has raised concerns over the long-term use of fish oil supplements, suggesting that a key omega-3 fatty acid may interfere with brain repair after repeated mild traumatic brain injuries and could be linked to protein changes associated with Alzheimer's disease.

The research, published in the journal Cell Reports, found that eicosapentaenoic acid (EPA), commonly found in fish oil supplements, may reduce the brain's ability to heal itself following injury and may contribute to the accumulation of tau protein in brain tissue.

Fish Oil Study Links EPA to Reduced Brain Repair

The study, led by Onder Albayram, PhD, at the Medical University of South Carolina, examined how long-term fish oil supplementation affects brain recovery mechanisms. Using both mouse models and human brain microvascular endothelial cells, researchers focused on repeated mild traumatic brain injuries, a condition often seen in contact sports, military service, and accidental falls.

Findings showed that EPA, but not docosahexaenoic acid (DHA), was associated with reduced repair capacity in endothelial cells that line brain blood vessels. These cells are essential for regulating blood flow, maintaining the blood-brain barrier, and supporting tissue recovery after injury.

Researchers observed impaired vascular network formation and reduced wound healing activity in human cell models exposed to EPA under conditions designed to mimic fatty acid metabolism.

Tau Protein Buildup and Neurovascular Disruption

The study also identified vascular-associated accumulation of tau protein in the cortex of animal models following long-term fish oil supplementation combined with repeated head injuries. Tau is a protein linked to neurodegenerative conditions, including Alzheimer's disease and chronic traumatic encephalopathy.

The researchers reported that these changes occurred alongside disruptions in neurovascular coupling, a process that links brain activity to blood flow. In animal models, these biological changes were also associated with reduced spatial learning and memory performance.

According to the study authors, the findings suggest that the brain's vascular system may play a more active role in injury-related degeneration than previously understood, particularly in the context of repeated mild traumatic brain injury.

EPA Effects on Brain Blood Vessels Under Scrutiny

A key focus of the research was the behaviour of cerebrovascular endothelial cells, which form the inner lining of brain blood vessels. These cells regulate oxygen delivery, metabolic exchange, and tissue repair processes.

Researchers found that EPA appeared to directly impair these cells' ability to recover after injury-like conditions. This effect was not observed with DHA, indicating a possible difference in how individual omega-3 fatty acids interact with brain repair mechanisms.

The study suggests that under certain biological conditions, dietary components such as EPA may influence how effectively the brain responds to repeated injury.

Fish Oil Supplements Not Rejected for General Use

Medical experts not involved in the study have stressed that the findings do not suggest fish oil supplements are broadly harmful. Instead, they highlight a potentially specific risk for individuals exposed to repeated head trauma.

Dr Dung Trinh, an internist and chief medical officer of Healthy Brain Clinic, said the results should be interpreted cautiously, noting that brain health outcomes vary widely depending on underlying conditions such as trauma history, vascular health and metabolic factors.

He said the findings are most relevant to groups such as athletes, veterans, and individuals with recurrent concussions, and advised that supplement use should be discussed with a healthcare professional, particularly regarding EPA-rich formulations.

Brain Health Diet Context and Omega-3 Sources

Nutrition specialists emphasise that omega-3 fatty acids remain an important part of a balanced diet when obtained from whole food sources. Diets such as the Mediterranean and MIND diet patterns are widely associated with cognitive health benefits.

Recommended dietary sources include fatty fish such as salmon, sardines, mackerel, and trout, which naturally contain both EPA and DHA. Plant-based sources such as walnuts, flaxseeds, and chia seeds also provide alpha-linolenic acid, although conversion to active omega-3 forms is limited.

Experts also highlight the importance of overall dietary patterns, hydration and reduced intake of ultra-processed foods in supporting brain vascular health and reducing inflammation.

Study Limitations and Need for Human Research

Researchers noted that the findings are based on animal and cellular models, meaning they cannot yet confirm that the same effects occur in humans. The dose of EPA used in experimental conditions may not directly reflect typical human supplement intake.

Further clinical studies are needed to determine whether long-term fish oil supplementation has similar effects in people, particularly those with or without a history of repeated brain injury.