A new study from the Medical University of South Carolina is raising fresh concerns about fish oil supplements, especially for people who experience repeated mild traumatic brain injuries. Writing in the journal Cell Reports, researchers report that these widely used supplements, often promoted as protective for the brain, could actually interfere with healing after injury.
The research was led by neuroscientist Onder Albayram, Ph.D., an associate professor at MUSC and a member of the National Trauma Society Committee. His team focused on the biological processes involved in repairing blood vessels in the brain after injury.
Rising Popularity of Omega-3 Supplements
Interest in omega-3 fatty acids, the key components of fish oil, has been growing rapidly. According to Fortune Business Insights, these supplements are now appearing not only in capsules but also in drinks, dairy alternatives, and snack products.
That surge in popularity does not surprise Albayram. “Fish oil supplements are everywhere, and people take them for a range of reasons, often without a clear understanding of their long-term effects,” he said.
“But in terms of neuroscience, we still don’t know whether the brain has resilience or resistance to this supplement. That’s why ours is the first such study in the field.”
Albayram collaborated with Eda Karakaya, Ph.D., Adviye Ergul, M.D., Ph.D., and several other researchers at MUSC and partner institutions. Among them was Semir Beyaz, Ph.D., at the Cold Spring Harbor Laboratory Cancer Center in New York.
EPA Identified as a Potential Weak Point in Brain Recovery
The team discovered what they describe as a context-dependent metabolic vulnerability. In simple terms, this means that changes in how cells use energy may reduce the brain’s ability to recover under certain conditions. This vulnerability appears to be linked to the buildup of eicosapentaenoic acid, or EPA, one of the main omega-3 fatty acids found in fish oil.
In their experimental models, higher levels of EPA in the brain were associated with weaker repair after injury.
Albayram noted that not all omega-3s behave the same way. Docosahexaenoic acid, or DHA, is well known for its beneficial role in the brain and is a major part of neuronal membranes. EPA, however, follows a different pathway. It is less incorporated into brain structures, and its effects can vary depending on how long it is present and the surrounding biological conditions. Because of this, the long-term impact of omega-3 intake on brain recovery and blood vessel adaptation has remained unclear.
Experiments Link Diet, Brain Biology, and Recovery
To better understand these effects, the researchers used a series of models to connect diet, brain function, and healing. In mice, they examined how long-term fish oil use influenced the brain’s response to repeated mild head impacts. Their focus was on signals related to blood vessel stability and repair.
They also studied human brain microvascular endothelial cells, which form part of the barrier between the brain and the bloodstream. In these cells, EPA, but not DHA, was linked to reduced repair capacity, aligning with the findings from the animal models.
To extend the findings to real-world disease, the team analyzed postmortem brain tissue from individuals diagnosed with chronic traumatic encephalopathy (CTE) who had a history of repeated brain injury.
The researchers described the results as having “implications for precision nutrition, therapeutic strategies and the design of dietary interventions targeting brain injury and neurodegeneration.”
Key Findings From the Study
The study identified several major patterns, which are summarized below along with simplified explanations.
- EPA-driven neurovascular instability triggers perivascular tauopathy and cognitive decline following TBI.
“In a sensitive brain state modeled in mice, long-term fish oil supplementation revealed a delayed vulnerability. The animals showed poorer neurological and spatial learning performance over time, together with clear evidence of vascular-associated tau accumulation in the cortex, linking impaired recovery to neurovascular dysfunction and perivascular tau pathology,” Albayram said.
- EPA reprograms cortical transcriptional responses and suppresses angiogenic signaling following traumatic brain injury.
“In the injured cortex, the team observed a coordinated shift in gene programs that normally support vascular stability and repair,” Albayram said. “The pattern included reduced expression of genes tied to extracellular matrix organization and endothelial integrity, alongside broader changes consistent with altered lipid handling after injury.”
- EPA utilization under permissive metabolic conditions impairs angiogenesis and endothelial integrity, recapitulating post-traumatic brain injury cerebrovascular dysfunction.
Albayram said that in human brain microvascular endothelial cells, EPA did not act as a universal toxin. “Instead, when cells were placed in conditions that encouraged fatty acid engagement, EPA was associated with weaker angiogenic network formation and reduced endothelial barrier integrity, matching key features of the neurovascular repair deficit seen in vivo.”
- CTE brain reveals neurovascular and fatty acid metabolic reprogramming consistent with EPA-linked vulnerability.
“In postmortem cortex from neuropathologically confirmed CTE cases with a history of repetitive brain injury, the researchers found evidence of disrupted fatty acid balance and broad transcriptional changes affecting vascular and metabolic pathways,” Albayram said. “This human arm was used to provide translational context, asking whether chronic disease tissue shows convergent signatures of altered lipid handling and reduced vascular stability.”
What the Findings Mean for Fish Oil Use
Albayram stressed that the study should not be interpreted as a blanket warning against fish oil. “I am not saying fish oil is good or bad in some universal way,” he said. “What our data highlight is that biology is context-dependent. We need to understand how these supplements behave in the body over time, rather than assuming the same effect applies to everyone.”
The researchers hope their work encourages a more careful look at omega-3 supplementation, both in clinical settings and among the general public. Their experiments focused on a specific scenario, repeated mild brain injury, and used CTE tissue to provide supporting observations rather than direct proof of cause and effect.
“As with any study, there are important boundaries,” Albayram said. “In the human CTE tissue, we can observe patterns, but we cannot prove what drove them. We also cannot capture every variable that shapes omega-3 handling in real life, including overall diet, health status and lifestyle.”
Next Steps in Understanding Omega-3 Effects
The team plans to continue investigating how EPA moves through the body, including how it is absorbed, transported, and distributed. They are especially interested in the mechanisms that control fatty acid movement.
“This paper is a starting point,” Albayram said, “but it is an important one. It opens a new conversation about precision nutrition in neuroscience, and it gives the field a framework to ask better, more testable questions.”
