DHA (omega-3) (2015-2019) & Alzheimers


Learn more about protecting cognitive capacity.

Researchers investigated whether fish oil supplementation would support cognitive capacity and slow brain atrophy in aged patients. They evaluated more than 800 patients, 229 with normal cognitive capacity, 397 with mild impairment, and 193 with Alzheimer's disease. Patients were tested using standard neuropsychological testing and brain MRI's at 6 months intervals over a 4 year period - in order to determine patients' ability to retain information and the size (volume) of the brain (cerebral cortex, hippocampus, ventricular volumes).

The researchers reported that taking fish oil supplements correlated with better standard memory and cognitive ability, and with less brain shrinkage - a tangible result of the development of Alzheimer's.

The benefit of fish oil supplements was most evident in the normal test group suggesting that the DHA omega-3 fatty acid is helpful for protecting the brain's health in later life.

The study did not specify the dosage, but the World Health Organization recommends EPA and DHA dosages of 300mg to 500mg daily and ALA of 800mg to 1100mg daily.1

Because of the close link between AD and lipid metabolism, DHA2 (and EPA) are both important.3, 4 Modulation of lipid composition in the brain by DHA improves behavior motor function and survival.5 It promotes brain-derived nerve factor,6 supports cognition,7 and enhances neurogenesis. It supports cell differentiation, maturation, neuron survival, reducing inflammation, and well as reduced amyloid beta (A-β) build-up.8

It is possible that the phospholipid form of DHA, found in fish, but not in fish oil supplements, is more effective, especially for those people who carry APOE4, the strongest risk factor for Alzheimer's.9

Note. DHA is also found in fish and omega-3 fatty acid supplements, as well as algae for vegetarians.


1. Daiello LA, Gongvatana A, Dunsiger S, Cohen RA, Ott BR. (2015). Association of fish oil supplement use with preservation of brain volume and cognitive function, Alzheimer's & Dementia. J Alz Ass. Feb.
2. Dyall SC. (2015). Long-chain omega-3 fatty acids and the brain: a review of the independent and shared effects of EPA, DPA, and DHA. Front Aging Neurosci. Apr 21;7:52.
3. Grimm MOW, Michaelson DM, Hartmann T. (2017). Omega-3 fatty acids, lipids, and apoE lipidation in Alzheimer's disease: a rationale for multi-nutrient dementia prevention. J Lipid Res. Nov;58(11):2083-2101.
4. Cardoso C, Afonso C, Bandarra NM. (2016). Dietary DHA and health: cognitive function aging. Nutr Res Rev. Dec;29(2):281-294.
5. Mohaibes RJ, Fiol-deRoque MA, Torres M, Ordinas M, Lopez DJ, et al. (2017). The hydroxylated form of docosahexaenoic acid (DHA-H) modifies the brain lipid composition in a model of Alzheimer's disease, improving behavioral motor function and survival. Biochem Biophy Acta Biomembr. Sep;1859(9 Pt B):1596-1603.
6. Matsuoka Y, Nishi D, Tanima Y, Itakura M, Kojima A, et al. (2015). Serum pro-BDNF/BDNF as a treatment biomarker for response to docosahexaenoic acid in traumatized people vulnerable to developing psychological distress: a randomized controlled trial. Transl Psychiatry. Jul 7;5:e596.
7. Weiser MJ, Butt CM, Mohajeri MH. (2016). Docosahexaenoic Acid and Cognition throughout the Lifespan. Nutrients. Feb 17;8(2):99.
8. Ibid. Grimm. (2017).
9. Patrick RP. (2019). Role of phosphatidylcholine-DHA in preventing APOE4-associated Alzheimer's disease. FASEB J. Feb;33(2):1554-1564.