A new study from the Medical University of South Carolina raises new concerns about fish oil supplements, especially for people who have experienced repeated mild traumatic brain injuries. Writing in the journal Cell Reports, researchers report that these widely used supplements, often touted as protecting the brain, may actually impede healing after injury.
The study was led by neuroscientist Onder Albayram, Ph.D., an associate professor at MUSC and a member of the National Trauma Association Committee. His team focused on the biological processes involved in repairing blood vessels in the brain after injury.
The growing popularity of omega-3 supplements
Interest in omega-3 fatty acids, a major component of fish oil, is rapidly increasing. According to Fortune Business Insights, these supplements are now appearing in capsules as well as beverages, dairy alternatives, and snack products.
The surge in popularity comes as no surprise to Albayram. “Fish oil supplements are ubiquitous, and people take them for a variety of reasons, often without a clear understanding of their long-term effects,” he says.
“But from a neuroscience perspective, we don’t yet know whether the brain is resilient or tolerant to this supplement. That’s why our study is the first in this field.”
Albayram collaborated with Eda Karakaya, Ph.D., Advye Ergul, MD, and several other researchers from MUSC and partner institutions. Among them was Dr. Semir Beyaz of the Cold Spring Harbor Laboratory Cancer Center in New York.
EPA identified as a potential weak link in brain recovery
The research team discovered what they describe as a context-dependent metabolic vulnerability. Simply put, this means that changes in the way cells use energy can reduce the brain’s ability to recover under certain conditions. This vulnerability appears to be related to the accumulation of eicosapentaenoic acid (EPA), one of the major omega-3 fatty acids found in fish oil.
In their experimental model, they found that higher levels of EPA in the brain were associated with less repair after injury.
Albayram pointed out that not all omega-3s work the same. Docosahexaenoic acid (DHA) is well known for its beneficial role in the brain, making up a major part of neural membranes. But the EPA takes a different route. Uptake into brain structures is low, and its effects vary depending on length of existence and surrounding biological conditions. Therefore, the long-term effects of omega-3 intake on brain recovery and vascular adaptation remain unclear.
Experiment links diet, brain biology and recovery
To better understand these effects, researchers used a series of models to link diet, brain function, and healing. They used mice to examine how long-term use of fish oil affected the brain’s response to repeated mild head impacts. They focused on signals related to vascular stability and repair.
They also studied human brain microvascular endothelial cells, which form part of the barrier between the brain and blood flow. In these cells, EPA, but not DHA, was associated with decreased repair capacity, consistent with results from animal models.
To extend this finding to real-world diseases, the research team analyzed postmortem brain tissue from individuals diagnosed with chronic traumatic encephalopathy (CTE) and who had a history of repeated brain injuries.
The researchers said the results “have implications for the design of precision nutritional management, treatment strategies, and dietary therapies targeting brain injury and neurodegeneration.”
Key findings from the research
The study identified several key patterns. They are summarized below with a brief explanation.
- EPA-induced neurovascular instability leads to perivascular tauopathy and cognitive decline after traumatic brain injury.
“In a hypersensitive brain state modeled in mice, we found that long-term supplementation with fish oil delayed vulnerability. The animals showed decreased neurological and spatial learning abilities over time, along with clear evidence of vascular-associated tau accumulation in the cortex, linking impaired recovery with neurovascular dysfunction and perivascular tau pathology,” Albayram said.
- EPA reprograms cortical transcriptional responses and suppresses angiogenic signaling after traumatic brain injury.
“In the injured cortex, the research team observed coordinated changes in genetic programs that normally support blood vessel stability and repair,” Albayram said. “This pattern included reduced expression of genes related to extracellular matrix organization and endothelial integrity, along with widespread changes consistent with altered lipid handling after injury.”
- Utilization of EPA under permissive metabolic conditions impairs angiogenesis and endothelial integrity, recapitulating cerebrovascular dysfunction following post-traumatic brain injury.
Albayram said that EPA does not act as a universal toxin in human brain microvascular endothelial cells. “Instead, when cells were placed in conditions that promoted fatty acid binding, EPA was associated with weakened angiogenic network formation and decreased endothelial barrier integrity, consistent with key features of neurovascular repair defects seen in vivo.”
- CTE brain reveals neurovascular and fatty acid metabolic reprogramming consistent with EPA-related vulnerability.
“In the postmortem cortex of CTE cases with neuropathologically confirmed history of repetitive brain injury, researchers found evidence of disruption of fatty acid balance and widespread transcriptional changes affecting vascular and metabolic pathways,” Albayram said. “This human arm was used to provide a translational context to ask whether chronically diseased tissues show converging signs of altered lipid handling and decreased vascular stability.”
What the findings mean for fish oil use
Albayram stressed that this study should not be interpreted as a blanket warning against fish oil. “I’m not saying fish oil is good or bad in a universal sense,” he said. “What our data highlights is that biology is context-dependent. We need to understand how these supplements work in the body over time, rather than assuming the same effects apply to everyone.”
The researchers hope their study will prompt more careful consideration of omega-3 supplements, both in clinical settings and in the general public. Their experiments focused on a specific scenario of repeated mild brain injury and used CTE tissue to provide supporting observations rather than directly proving cause and effect.
“As with any research, there are important boundaries,” Albayram says. “In human CTE tissues, we can observe patterns, but we cannot prove what caused those patterns. We also cannot capture all the variables that shape omega-3 handling in real life, such as overall diet, health, and lifestyle.”
Next steps to understanding the effects of omega-3s
The research team will continue to investigate how EPA moves through the body, including how it is absorbed, transported and distributed. They are particularly interested in the mechanisms that control fatty acid movement.
“This paper is a starting point, but it is an important one, opening up new conversations about precision nutrition in neuroscience and giving the field a framework to ask better, more testable questions,” Albayram said.
