11/04/2026
Our Brian’s don’t just need omega 3s, omega 3s are a core component of your brains neuro chemistry
- but don’t take it from me, see a PhD biochemist break it down in this infographic.
***And no u can’t get enough omega 3 from ALA (ALA is mislabeled as an omega 3) it has a conversion rate of 1-3% into omega 3, which means the amounts of ALA in Chia/flaxseed/walnut we would need to eat to get optimal amounts of omega 3s is not practically achievable (Lily Nichols, RDN breaks this down in her articles)
Most omega-3 marketing talks about fish oil "supporting brain health" as though it acts on the brain from the outside. The biology is more fundamental than that. DHA is not simply something your brain uses. It is something your brain is physically made from.
Docosahexaenoic acid (DHA) is a 22-carbon fatty acid with six double bonds. It constitutes approximately 40% of all polyunsaturated fatty acids in the brain and over 90% of the brain's omega-3 content. EPA, by comparison, is 250 to 300 times lower in concentration. When people say "omega-3 for the brain," the molecule that matters structurally is DHA.
DHA sits primarily at the sn-2 position of phosphatidylethanolamine and phosphatidylserine, two of the dominant phospholipids in neuronal membranes. Each of its six double bonds introduces a bend in the carbon chain. Those accumulated kinks prevent the tails from packing tightly, which increases membrane fluidity. That fluidity is not abstract. It determines how quickly every receptor, ion channel, and signaling protein embedded in the membrane can change conformation in response to a signal.
McNamara et al. (2007, Biological Psychiatry) measured the total fatty acid composition of postmortem orbitofrontal cortex (Brodmann Area 10) in 15 patients with major depressive disorder and 27 age-matched controls. After correction for multiple comparisons, DHA was the only fatty acid that was significantly different. MDD patients had 22% less DHA in this region. The deficit was greater in women (32%) than in men (16%), and could not be wholly attributed to lifestyle factors or postmortem tissue variables.
An important nuance: this deficit appears to be region-specific. Later studies from the same group found no significant DHA differences in the amygdala, hippocampus, entorhinal cortex, or other prefrontal areas. The orbitofrontal cortex, the region involved in decision-making, reward evaluation, and emotional regulation, was selectively affected. That specificity makes the finding more precise, not less meaningful.
This is a single postmortem study with a small sample size, and it establishes association, not causation. We cannot say DHA deficiency caused the depression. But the structural role of DHA in the membrane is not in question, and the selective deficit in a region central to mood regulation is worth paying attention to.
Practically: DHA is not synthesized efficiently from plant-based ALA. Conversion rates from ALA to DHA in humans are estimated at less than 1% in most studies. Preformed DHA comes from fatty fish, fish oil, algal oil, and to a lesser extent eggs and organ meats. If you are supplementing omega-3 for brain-related reasons, the DHA content per serving matters more than the total omega-3 on the label. Many products are EPA-dominant. For structural brain composition, DHA is the relevant molecule.
McNamara et al., Biol Psychiatry, 2007.
Weiser et al., Nutrients, 2016.
