Bigger Brain Volume, Better Function

A 2022 study—widely discussed in subsequent years—found that adults with higher levels of omega-3 fatty acids had notably larger brain volumes. In particular, the hippocampus, the region responsible for memory formation and learning, was significantly larger in those with elevated omega-3 status. Participants in the top 25% for omega-3 levels showed greater total brain volume and hippocampal size compared to those in the lowest quartile.

The implications are substantial. Researchers observed that individuals with lower omega-3 levels exhibited brain characteristics equivalent to approximately two additional years of structural aging. In contrast, higher levels appeared to help preserve brain integrity.

Cognitive Benefits: Memory and Executive Function

Beyond physical brain structure, omega-3s are also associated with enhanced cognitive performance. Individuals with higher levels demonstrated stronger visual memory and improved executive function—skills that include problem-solving, planning, and attention control.

These findings reinforce the idea that omega-3 fatty acids, particularly DHA and EPA, play a functional role in maintaining mental sharpness as we age.

Reducing the Risk of Cognitive Decline

Long-term studies and meta-analyses further suggest that regular, moderate intake of omega-3s may reduce the risk of cognitive decline and dementia by around 20%. While not a cure, omega-3s appear to offer a protective effect, especially when consumed consistently over time.

Importantly, the timing of intake matters. Maintaining adequate omega-3 levels during midlife has been identified as a key factor in preserving brain structure and reducing the likelihood of dementia later on.

Prevention, Not Cure

Researchers emphasise that omega-3s are most effective as a preventive strategy rather than a treatment. Their benefits are most pronounced before significant cognitive decline occurs or in the earliest stages of impairment. This positions omega-3 intake as a proactive measure—something to prioritise well before symptoms arise.

Diet Matters: Supporting Evidence

Supporting this perspective, research published in the American Journal of Clinical Nutrition in 2026 found that individuals with higher adherence to the MIND diet—a dietary pattern rich in brain-supportive nutrients including healthy fats—experienced slower grey matter shrinkage. The effect was equivalent to delaying brain aging by approximately 2.5 years.

Where to Get Omega-3s

The most beneficial omega-3 fatty acids for brain health—EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid)—are primarily found in oily fish such as salmon, mackerel, and sardines, as well as in high-quality fish oil supplements such as Equazen.

Conclusion

The science is increasingly clear: omega-3 fatty acids are a valuable ally in maintaining brain health. From preserving brain volume to supporting memory and potentially reducing the risk of dementia, their role is both structural and functional.

Incorporating omega-3s into your diet—particularly during midlife—may be one of the simplest and most effective steps you can take to support cognitive longevity.

References

• Research published in Neurology, the medical journal of the American Academy of Neurology
• The American Journal of Clinical Nutrition