DOCOSAHEXAENOIC ACID

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The chemical structure of docosahexaenoic acid showing physiological numbering (red) and chemical numbering (blue) conventions.
Chemical name
Chemical formula
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PubChem	445580
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'Docosahexaenoic acid' (commonly known as 'DHA'; 22:6(ω-3), ''all-cis''-docosa-4,7,10,13,16,19-hexaenoic acid; trivial name 'cervonic acid') is an omega-3 essential fatty acid. Chemically, DHA is a carboxylic acid with a 22-carbon chain and six ''cis'' double bonds; the first double bond is located at the third carbon from the omega end.
DHA is most often found in fish oil. Most of the DHA in fish and other more complex organisms originates in microalgae of the genus ''Schizochytrium'', and concentrates in organisms as it moves up the food chain. DHA is also commercially manufactured from ''Crypthecodinium cohnii''. History of Martek Martek Biosciences Corporation Most animals make very little DHA metabolically, however small amounts are manufactured internally through the consumption of α-linolenic acid, an omega-3 fatty acid found in chia, flax, and many other seeds and nuts.
DHA is a major fatty acid in sperm and brain phospholipids, and especially in the retina. Dietary DHA can reduce the level of blood triglycerides in humans, which may reduce the risk of heart disease. Low levels of DHA cause reduction of brain serotonin levels Latest Publications on the Link between DHA and Intelligence / The Brain. Cambridge Applied Polymers Ltd. and have been associated with ADHD, Alzheimer's disease, and depression, among other diseases, and there is mounting evidence that DHA supplementation may be effective in combating such diseases (see external links at the end of this article).

Contents

Metabolic synthesis

DHA in Alzheimer's Disease

DHA Inhibiting Human Carcinoma in Mice

DHA in breast milk and infant formula

Superiority of Algae Derived DHA in Infant Nutrition

DHA Studies of Vegans and Vegetarians

Promotion of DHA as a food additive

See also

References

Metabolic synthesis

In the human body, DHA is either present in the diet or it is derived from eicosapentaenoic acid (EPA, 20:5, ω-3) via docosapentaenoic acid (DPA, 22:5 ω-3) as an intermediate. This is done with an elongation step followed by the action of Δ4-desaturase. Another pathway has also been described in peroxysomes and mitochondria. EPA is twice elongated yielding 24:5 ω-3, then desaturated to 24:6 ω-3, then shortened to DHA (22:6 ω-3) via beta oxidation. This pathway is known as 'Sprecher's shunt'. n-3 Fatty acids and the inflammatory response – biological background De Caterina, R and Basta, G The metabolism of 7,10,13,16,19-docosapentaenoic acid to 4,7,10,13,16,19-docosahexaenoic acid in rat liver is independent of a 4- desaturase Voss, M Reinhart, S Sankarappa and H Sprecher

DHA in Alzheimer's Disease

A large NIH drug trial is currently recruiting patients for evaluating DHA in Alzheimer's disease. ^[1] This is the first human trial of DHA. Animal studies in TG3 transgenic mouse model of Alzheimer's disease have shown decrease in amyloid plaques and tau by DHA. Animal studies also show that when combined with Arachidonic acid (another fatty acid present in fish oil) the effectiveness of DHA in preventing plaques was lesser than when used alone.

DHA Inhibiting Human Carcinoma in Mice

Researchers at the University of Nevada conducted a study on the effects of DHA supplementation on the growth of human colon adeno carcinoma in mice. The animals received one of four specialized diets: low fat with corn oil (omega-6 linoleic acid), high fat with corn oil (omega-6 linoleic acid), high fat with fish oil (omega-3 EPA and DHA), and high fat with algae-derived DHA (omega-3 DHA). At completion, the mice receiving a diet supplemented with algae-derived DHA had tumors that were smaller than those of mice receiving diets supplemented with omega-3 from fish oil as well as those fed both the high and low fat corn oil (omega-6) diets. These results indicate that algae-derived DHA possesses greater tumor suppressing properties than do corn or fish oil.
^[2]

DHA in breast milk and infant formula

DHA concentrations in breast milk range from 0.07% to greater than 1.0% of total fatty acids, with a mean of about 0.34%. DHA levels in breast milk are higher if a mother's diet is high in fish.
DHA has been an ingredient in several brands of premium infant formula sold in North America since 2001 after Mead Johnson, the first infant formula manufacturer to add DHA and ARA (arachodonic acid) to its Enfamil Lipil product, received approval by the Food and Drug Administration and Health Canada. Both DHA and ARA are permitted in infant formula as both are components of human breast milk. The addition of DHA at dose effective levels has been shown to improve congitive function in both term and preterm infants.
DHA makes infant formula more like human milk than "conventional" formula containing linolenic acid and linoleic acid, which are s to DHA. Formula sold in North America uses lipids from microorganisms grown in bioreactors as sources of DHA. SOLVENTLESS EXTRACTION PROCESS Connell, Gary, J. ''et al'' A patent at the WIPO. Martek DHA and ARA Introduction

Superiority of Algae Derived DHA in Infant Nutrition

A study Growth and development of preterm infants fed infant formulas containing docosahexaenoic acid and arachidonic acid, Clandinin M, Van Aerde J, Merkel K, Harris C, Springer M, Hansen J, Diersen-Schade D, , , J Pediatr, 2005 found that preterm infants fed baby formulas fortified with DHA derived directly from algae gained weight faster than infants fed formula fortified with DHA from fish oil. Additionally, there are no risks of harmful contaminants such as methyl mercury or dioxins, which may be present in fish and fish oils. This is especially important for pregnant and nursing women and young children.

DHA Studies of Vegans and Vegetarians

Vegans and vegetarians have markedly lower stores of DHA. Their bodily DHA levels do not rise much even with high dietary levels of linolenate. This, and features of the production and distribution of DHA in pregnant and lactating women, indicates that DHA ''per se'' is an essential nutrient.
Is docosahexaenoic acid (DHA) essential? Lessons from DHA status regulation, our ancient diet, epidemiology and randomized controlled trials, Muskiet F, Fokkema M, Schaafsma A, Boersma E, Crawford M, , , J Nutr, 2004

Promotion of DHA as a food additive

DHA is actively promoted by its major manufacturers, Martek Biosciences and Ocean Nutrition Canada, as a food additive. Until recently sales other than to makers of infant formula have been minimal; however, in 2007 several DHA-fortified dairy items (milk, yogurt) began selling in grocery stores. In anticipation of demand Martek had by 2007 increased its manufacturing capacity to three times the amount which was able to sell.
There is less DHA available in the average diet than formerly due to cattle being taken off grass and fed grain before butchering; likewise there is less in eggs due to factory farming. DHA is widely believed to be helpful to people with a history of heart disease, for premature infants, and to support healthy brain development especially in young children. Some manufactured DHA is a vegetarian product extracted by a patented process from algae, but costs approximately twice as much as fish oil. Both are odorless and tasteless after processing. Magical or Overrated? A Food Additive in a Swirl Gary Rivlin

See also

★ List of omega-3 fatty acids

★ Polyunsaturated fatty acids

References

1. DHA Phase 3 trial in Alzheimer's disease National Institute on Aging
2. Martek Biosciences's DHA Shown To Inhibit Human Colon Carcinoma In Mice.