Omega-3 Fatty Acids & Cognitive Aging: What the Evidence Shows

Omega-3 polyunsaturated fatty acids — specifically EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) — are essential structural components of neuronal membranes. The human brain is approximately 60% fat, with DHA comprising up to 97% of the omega-3 fatty acids found in brain tissue.

A 2022 meta-analysis in Nutrients reviewed 22 randomized controlled trials and found that omega-3 supplementation significantly improved episodic memory and global cognitive function in adults with mild cognitive impairment. The effect was strongest in participants with low baseline omega-3 index — which includes the majority of Western adults eating typical diets.

“The combination of adequate protein and high omega-3 index was associated with significantly better cognitive resilience in women over 60 than either factor alone.”

Salmon and fatty fish are among the most bioavailable dietary sources of EPA and DHA — the same forms the brain uses directly. Plant-based omega-3 sources (flaxseed, walnuts) provide ALA, which the body converts to EPA/DHA at only 5–10% efficiency.

Critically, omega-3 status appears to interact with protein intake for brain health: a 2024 review in Frontiers in Aging Neuroscience found that the combination of adequate protein and high omega-3 index was associated with significantly better cognitive resilience in women over 60 than either factor alone.