Docosahexaenoic acid (DHA)

Docosahexaenoic acid or DHA is one of the three main types of polyunsaturated Omega-3 fatty acids. The other two are eicosapentaenoic (EPA) and Alha-lioleic acid (ALA). Since DHA and EPA are mainly derived from fish, they are also at times known as marine omega-3s. ALA is the plant based Omega-3. DHA is a key component of the brain making up a galloping 97% of the fats found in the brain in addition to accounting for 93% of the fats in the retina. It is also a significant component of the heart.

Omega-3s, among them DHA make up a fundamental part of the cell membranes in the entire body and influence the cell receptors found in the said membranes. They also make available the starting point for the assembly of hormones responsible for clotting of blood, inflammation and artery wall contractions and relaxations. Finally, Omega-3s unite with cells responsible for regulation of genetic function.

While there are no disputes regarding the health benefits of Omega-3 fats, not many realize the differences in the three main types of acids.  EPA and DHA constitute the major portion of the Omega-3s but their ratio in commercial preparations varies greatly. Typically they contain higher quantities of EPA, simply because it is the cheaper of the two and it also gives off less fishy odour making it easier to ingest. However, according to research, it is DHA that offers the maximum neurological advantages.

Tremendous amount of interest has been generated in Omega-3s in the recent past. This is due to a large amount of research which indicates that these essential acids are vital to good health at every stage of life. A Swedish study indicates that DHA is closely associated with optimum bone mineral density in healthy adults.1 A separate study found that top 20% of its participants with the highest levels of plasma DHA showed 47% decrease in development of dementia.2 Controlled omega-3 studies point to their ability to protect against ischemic stroke, a primary source of long-term disability.3 Enhanced intake of Omega-3 fatty acids is also associated with healthy cognitive function in later years.4 One study using boys and girls between the ages of nine to twelve years of age found that supplementing their diets with omega-3s diminished reckless behaviour, particularly in girls.5

Due to the complex relationship of Omega-3 acids with the different systems of the body both at cellular and neurological levels, it is vital to ensure that optimal quantities of these oils are ingested.


  1. Hogstrom M, et al. n-3 Fatty acids are positively associated with peak bone mineral density and bone accrual in healthy men: the NO2 Study. Am J Clin Nutr, 2007. 85:803-7.
  2. Schaefer E, et al. Plasma phosphatidylcholine docosahexaenoic acid content and risk of dementia and Alzheimer disease: the Framingham Heart Study. Arch Neurol, 2006. 63:1545-50.
  3. He KA, et al. The puzzle of dietary fat intake and risk of ischemic stroke: a brief review of epidemiologic data. J Am Diet Assoc, 2007. 107:287-95.
  4. Whalley LJ, et al. Cognitive aging, childhood intelligence, and the use of food supplements: possible involvement of n-3 fatty acids. Am J Clin Nutr, 2004. 80:1650-7.
  5. Itomura M, Hamazaki K, Sawazaki S, et al. The effect of fish oil on physical aggression in schoolchildrenµa randomized, double-blind, placebo-controlled trial. J Nutr Biochem. 2005 Mar;16(3):163-71.
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By Andy

Hi, my name is Dr. Andy Williams and I am a biologist with a keen interest in diet and nutrition. This site was set up to help me explore the research, facts and fiction about Krill Oil. Please feel free to contact me if you have any comments, questions or suggestions.

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