DHA May Require a Special Form to Reach the Brain

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DHA (docosahexaenoic acid, the omega-3 fat concentrated in fish oil) makes up a large share of brain fat, and APOE4 carriers appear to have reduced DHA delivery to the brain. Standard fish oil supplements increase DHA in the bloodstream, but Davidson says DHA crosses the blood-brain barrier efficiently only in a specific chemical form called lysophosphatidylcholine (lyso-PC) DHA — a form the body has limited ability to produce from regular fish oil. This explains why DHA supplementation studies on cognition have shown little benefit, despite the biological plausibility.

A lyso-PC DHA supplement derived from krill oil is already on the market in limited form; a fish-oil-based version is in development. Davidson's research organization, Jocasta, plans to conduct studies documenting whether lyso-PC DHA actually increases brain DHA levels. For readers currently taking standard fish oil for brain health, the evidence does not yet support that benefit; for cardiovascular purposes, EPA appears to be the more evidence-backed component, and its mechanism appears to be anti-inflammatory and antithrombotic rather than triglyceride-lowering.