Docosahexaenoic acid

Docosahexaenoic acid
Docosahexaenoic acid
IUPAC name
(4Z,7Z,10Z,13Z,16Z,19Z)-docosa-4,7,10,13,16,19-hexaenoic acid; Doconexent
Other names
cervonic acid, DHA
Identifiers
CAS number 6217-54-5 YesY
PubChem 445580
ChemSpider 393183 YesY
UNII ZAD9OKH9JC YesY
ChEBI CHEBI:28125 YesY
ChEMBL CHEMBL367149 YesY
Jmol-3D images Image 1
Properties
Molecular formula C22H32O2
Molar mass 328.488 g/mol
Density 0.943 g/cm3
Melting point

-44 °C, 229 K, -47 °F
Boiling point

446.7 °C, 720 K, 836 °F
 YesY acid (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is a primary structural component of the human brain and retina[1] [2] . In chemical structure, DHA is a carboxylic acid with a 22-carbon chain[3] and six cis double bonds; the first double bond is located at the third carbon from the omega end.[4] Its trivial name is cervonic acid, its systematic name is all-cis-docosa-4,7,10,13,16,19-hexa-enoic acid, and its shorthand name is 22:6(n-3) in the nomenclature of fatty acids.

Cold-water oceanic fish oils are rich in DHA. Most of the DHA in fish and complex organisms with access to cold-water oceanic foods originates in photosynthetic and heterotrophic microalgae, and becomes increasingly concentrated in organisms, as they move up the food chain. DHA is also commercially manufactured from microalgae; Crypthecodinium cohnii and another of the genus Schizochytrium.[5] DHA manufactured using microalgae is vegetarian.[5] Some animals with access to seafood make very little DHA through metabolism, but obtain it in the diet. However, in strict herbivores, and carnivores that do not eat seafood, DHA is manufactured internally from α-linolenic acid, a shorter omega-3 fatty acid manufactured by plants (and also occurring in animal products as obtained from plants). Although α-linolenic acid (ALA) does convert to DHA in humans, the process is inefficient and very limited even in healthy individuals. DHA is a major fatty acid in sperm and brain phospholipids and in the retina. Dietary DHA may reduce the risk of heart disease by reducing the level of blood triglycerides in humans.[6] Below-normal levels of DHA have been associated with Alzheimer's disease.

Contents

Central nervous system constituent

DHA is the most abundant omega-3 fatty acid in the brain and retina. DHA comprises 40% of the polyunsaturated fatty acids (PUFAs) in the brain and 60% of the PUFAs in the retina. Fifty percent of the weight of a neuron's plasma membrane is composed of DHA.[7]

DHA modulates the carrier-mediated transport of choline, glycine, and taurine, the function of delayed rectifier potassium channels, and the response of rhodopsin contained in the synaptic vesicles, among many other functions.[8]

DHA deficiency is associated with cognitive decline.[9] Phosphatidylserine (PS) controls apoptosis, and low DHA levels lower neural cell PS and increase neural cell death.[10] DHA are reduced in the brain tissue of severely depressed patients.[11][12]

Metabolic synthesis

In humans, DHA is either obtained from the diet or synthesized from eicosapentaenoic acid (EPA, 20:5, ω-3) via docosapentaenoic acid (DPA, 22:5 ω-3) as an intermediate. This synthesis had been thought to occur through an elongation step followed by the action of Δ4-desaturase. It is now considered more likely that DHA is biosynthesized via a C24 intermediate followed by beta oxidation in peroxisomes. Thus, 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.[13][14]

Health

Attention Deficit Hyperactivity Disorder (ADHD)

Research on DHA supplementation and Attention Deficit Hyperactivity Disorder (ADHD) have shown mixed results. One study of pure DHA supplementation on children with ADHD found no behavioral improvements,[15] while another study found fish oil containing both EPA and DHA did improve behavior.[16]

Alzheimer's disease and decline of mental health

Preliminary studies indicated that DHA can slow the progression of Alzhiemer's disease in mice,[17][18] sparking interest in additional research. However, the first large-scale human trials showed that DHA did not slow decline of mental function in elderly people with mild to moderate Alzheimer's disease.[19] These trials were part of a large US National Institutes of Health (NIH) intervention study to evaluate DHA in Alzheimer's disease.[20]

Researchers from the National Institute on Aging-supported Alzheimer's Disease Cooperative Study conducted a double-blind, randomized, placebo-controlled clinical trial comparing DHA and placebo over 18 months in 402 people (average age=76) diagnosed with mild to moderate Alzheimer's at 51 sites. According to this study, treatment with DHA increased blood levels of DHA, and appeared to increase brain DHA levels, based on a measured increase of DHA in study participants' cerebrospinal fluid.

However, DHA treatment did not slow the rate of change on tests of mental function, global dementia severity status, activities of daily living, or behavioral symptoms in the study population as a whole. Treatment effects did not differ between the mild and moderate Alzheimer's patients, leading study authors to conclude that the results do not support the routine use of DHA for patients with Alzheimer's.

Animal studies in the TG3 transgenic mouse model of Alzheimer's disease had linked dietary DHA to decreases in amyloid plaques and tau. Animal studies also showed, when DHA was combined with arachidonic acid (also present in fish oil), plaque formation was greater with the arachidonic acid compared to DHA alone.

DHA deficiency likely plays a role in decline of mental function in healthy adults, which is indicated in a study from 2010 conducted at 19 U.S. clinical sites on 485 subjects aged 55 and older who met criteria for age-associated memory impairment. The study found algal DHA taken for six months decreased heart rate and improved memory and learning in healthy, older adults with mild memory complaints. These findings indicate the importance of early DHA intervention and provided a statistically significant benefit to cognitive function in individuals over 50 years of age.[21] Higher DHA levels in middle-aged adults is related to better performance on tests of nonverbal reasoning and mental flexibility, working memory, and vocabulary.[22]

Cancer

DHA was found to inhibit growth of human colon carcinoma cells,[23][24] more than other omega-3 PUFAs. The cytotoxic effect of DHA was not caused by increased lipid peroxidation or any other oxidative damage, but rather a decrease in cell growth regulators. However, different cancer lines handle PUFAs differently and display different sensitivities toward them. Such preliminary findings point to the need for further research, and are not proof DHA does or does not provide any benefit for intended treatment, cure, or mitigation of cancer. However, in 2008, DHA was shown to increase the efficacy of chemotherapy in prostate cancer cells,[25] and in 2009, a chemoprotective effect in a mouse model was reported.[26] One large clinical trial, the "Prostate Cancer Prevention Trial", found that DHA was correlated with an increase in high-grade prostate cancer.[27]

Pregnancy and lactation

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. The Food and Drug Administration has noted specific concerns for women who are pregnant or might become pregnant, nursing mothers, and young children regarding mercury levels in fish and shellfish.[28]

DHA has recently gained attention as a supplement for pregnant women, noting studies of improved attention and visual acuity. Given the recently gained attention, the majority of pregnant women in the U.S. fail to get the recommended amount of DHA in their diets.[29] One recent study indicated low levels of plasma and erythrocyte DHA were associated with poor retinal development, low visual acuity, and poor cognitive development. In that same study, alpha-linolenic acid was shown as a source of fetal DHA, but preformed DHA was more readily accredited. A working group from the International Society for the Study of Fatty Acids and Lipids recommended 300 mg/day of DHA for pregnant and lactating women, whereas the average consumption was between 45 mg and 115 mg per day of the women in the study. The March of Dimes recommends pregnant women consume at least 200 mg DHA per day.[30] Other requirements are available from other sources.[31]

Docosahexaenoic acid single-cell oil (DHASCO)[32][33] 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 DHASCO and arachidonic acid single-cell organism oil to its Enfamil Lipil product, received a "Generally Regarded As Safe" status by the Food and Drug Administration and Health Canada.

DHASCO does not make infant formulas more like human milk than "conventional" formula containing alpha-linolenic acid and linoleic acid, which are precursors to DHA. Formula sold in North America uses lipids from microorganisms grown in bioreactors as sources of DHA.[5][34] No scientific review studies show DHA additives benefit brain development of term infants, as formula makers claim in their advertisements, which has led some public interest groups to file complaints with the Federal Trade Commission of the United States, alleging false and misleading advertising.[35]

A study[36] found that preterm infants fed baby formulas fortified with DHASCO provided better developmental outcomes than formulas not containing the supplement.

A study sponsored by March of Dimes and National Institutes of Health suggests that pregnant moms who take DHA supplements during pregnancy give their babies some degree of added protection against getting common colds.[37] The babies whose mothers had taken DHA supplements seemed to get over cold symptoms faster when they did get sick.

Current Research

Although most studies demonstrate positive effects of dietary DHA on human health, contrary results exist. For example, one study[38] found that the use of DHA-rich fish oil capsules did not reduce postpartum depression in mothers or improve cognitive and language development in their offspring during early childhood.

Additional studies confirmed DHA benefits for other nervous system functions, cardiovascular health, and potentially other organs. In one study, men who took DHA supplements for 6–12 weeks decreased the concentrations of several inflammatory markers in their blood by approximately 20%.[39] It has been shown that heart disease patients with higher intakes of DHA and EPA survived longer.[citation needed] A new study found that higher intake of DHA was associated with slower rates of telomere shortening, which is a basic DNA-level marker of aging.[40] Preliminary studies showed that a high intake of DHA was associated with reduced risk for developing Alzheimer's disease,[citation needed] consistent with DHA being the most abundant omega-3 fatty acid in the brain. It is now considered so important to brain and eye development that DHA is included in most infant formulas.[41] Lastly, in preliminary research, it was found that a diet rich in DHA might protect stroke victims from brain damage and disability and aid in a speedier recovery.[42]

Nutrition

The Discovery of Algae-based DHA

In the early 1980s, NASA sponsored scientific research in search of a plant-based food source that could generate oxygen and nutrition on long-duration space flights. The researchers discovered that certain species of marine algae produced rich nutrients. This research led to the development of an algae-based, vegetable-like oil that contains two essential polyunsaturated fatty acids: DHA and ARA (Arachidonic acid).[43]

Use as a food additive

DHA is widely used as a food additive. It was first used primarily in infant formulas.[44] In 2004, the US Food and Drug Administration endorsed qualified health claims for DHA,[45] and by 2007 DHA-fortified dairy items (milk, yogurt, cooking oil) started to appear in grocery stores.

DHA is 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 along with supporting retinal development. Some manufactured DHA is a vegetarian product extracted from algae, and it competes on the market with fish oil that contains DHA and other omega-3's such as EPA. Both fish oil and DHA are odorless and tasteless after processing as a food additive .[46]

Studies of vegetarians and vegans

Main article: Vegetarian nutrition#Omega-3 fatty acids

Vegetarian diets typically contain limited amounts of DHA, and vegan diets typically contain no DHA. Vegetarians and vegans have substantially lower levels of DHA in their bodies, and short-term supplemental ALA has been shown to increase EPA, but not DHA. However, supplemental preformed DHA, available in algae-derived oils or capsules, has been shown to increase DHA levels. While there is little evidence of adverse health or cognitive effects due to DHA deficiency in adult vegetarians or vegans, fetal and breast milk levels remain a concern.[47]

DHA and EPA in fish oils

Fish oil is widely sold in gelatin capsules containing a mixture of omega-3 fatty acids including EPA and smaller quantities of DHA. One study found fish oil higher in DHA than EPA lowered inflammatory cytokines, such as IL-6 and IL-1β, associated with neurodegenerative and autoimmune diseases. They note the brain normally contains DHA, but not EPA, though both DHA and EPA plasma concentrations increased significantly for participants.[48]

Hypothesized role in evolution

An abundance of DHA in seafood has been suggested as being helpful in the development of a large brain,[49] though other researchers claim a terrestrial diet could also have provided the necessary DHA.[50]

See also

Notes and references

  1. ^ "DHA FOR OPTIMAL BRAIN AND VISUAL FUNCTIONING". DHA/EPA Omega-3 Institute. http://www.dhaomega3.org/Overview/DHA-for-Optimal-Brain-and-Visual-Functioning. 
  2. ^ Sears, Dr. William. "DHA as a Brain Food". Ask Dr. Sears. http://www.askdrsears.com/topics/family-nutrition/dha/dha-brain-food. 
  3. ^ docosa- is Greek for 22
  4. ^ The omega end is the one furthest from the carboxyl group.
  5. ^ a b c Martek Biosciences Corporation (5 April 2007). "History of Martek". Archived from the original on February 5, 2007. http://web.archive.org/web/20070205005919/http://aboutmartek.martek.com/history/. Retrieved March 10, 2007. 
  6. ^ Gary J. Nelson, Darshan S. Kelley. "DHA Lowers Blood Triglycerides in Diet Study". Agricultural Research (USDA). http://www.ars.usda.gov/is/AR/archive/sep98/dha0998.pdf. Retrieved September 1998. 
  7. ^ Meharban Singh (March 2005). "Essential Fatty Acids, DHA and the Human Brain from the Indian Journal of Pediatrics, Volume 72" (PDF). http://medind.nic.in/icb/t05/i3/icbt05i3p239.pdf. Retrieved October 8, 2007. 
  8. ^ Arthur A. Spector (1999). "Essentiality of Fatty Acids from Lipids, Vol. 34". http://www.springerlink.com/content/3547007r16268860/. Retrieved October 8, 2007. 
  9. ^ Lukiw WJ, Cui JG, Marcheselli VL, Bodker M, Botkjaer A, Gotlinger K, Serhan CN, Bazan NG. (2005 October). "A role for docosahexaenoic acid-derived neuroprotectin D1 in neural cell survival and Alzheimer disease". J Clin Invest. 115 (10): 2774–83. doi:10.1172/JCI25420. PMC 1199531. PMID 16151530. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1199531. 
  10. ^ Serhan CN, Gotlinger K, Hong S, Arita M (2004). "Resolvins, docosatrienes, and neuroprotectins, novel omega-3-derived mediators, and their aspirin-triggered endogenous epimers: an overview of their protective roles in catabasis". Prostaglandins Other Lipid Mediat. 73 (3-4): 155–72. doi:10.1016/j.prostaglandins.2004.03.005. PMID 15290791. 
  11. ^ McNamara RK, Hahn CG, Jandacek R, et al. (2007). "Selective deficits in the omega-3 fatty acid docosahexaenoic acid in the postmortem orbitofrontal cortex of patients with major depressive disorder". Biol. Psychiatry 62 (1): 17–24. doi:10.1016/j.biopsych.2006.08.026. PMID 17188654. 
  12. ^ "DHA Deficit Detected in Frontal Cortex of Severely Depressed Patients". Fats of Life. September 2007. http://fatsoflife.com/pufa/article.asp?nid=1&edition=this&id=493. Retrieved 2007-10-31. 
  13. ^ De Caterina, R and Basta, G (June 2001). "n-3 Fatty acids and the inflammatory response – biological background". European Heart Journal Supplements 3 (Supplement D): D42–D49. doi:10.1016/S1520-765X(01)90118-X. 
  14. ^ A Voss, M Reinhart, S Sankarappa and H Sprecher (October 1991). "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". The Journal of Biological Chemistry 266 (30): 19995–20000. PMID 1834642. http://www.jbc.org/content/266/30/19995.full.pdf+html. Retrieved January 2, 2011. 
  15. ^ Voigt RG, Llorente AM, Jensen CL, Fraley JK, Berretta MC, Heird WC. (2001 Aug). "A randomized, double-blind, placebo-controlled trial of docosahexaenoic acid supplementation in children with attention deficit/hyperactivity disorder.". J Pediatr. 139 (2): 173–4. doi:10.1067/mpd.2001.116050. PMID 11487742. 
  16. ^ Sinn N, Bryan J. (2007 Apr). "Effect of supplementation with polyunsaturated fatty acids and micronutrients on learning and behavior problems associated with child ADHD.". J Dev Behav Pediatr. 28 (2): 139–44. doi:10.1097/01.DBP.0000267558.88457.a5. PMID 17435458. http://www.dhaomega3.org/Cognitive-Performance/Effect-of-Supplementation-with-Polyunsaturated-Fatty-Acids-and-Micronutrients-on-Learning-and-Behavior-Problems-Associated-with-Child-ADHD. 
  17. ^ "DHA Fights Alzheimer’s Brain Plaques in Mice". US Department of Veterans Affairs. 
  18. ^ Lim, Giselle,; Frederic Calon, Takahashi Morihara, et al (March 23, 2005). "A Diet Enriched with the Omega-3 Fatty Acid Docosahexaenoic Acid Reduces Amyloid Burden in an Aged Alzheimer Mouse Model". The Journal of Neuroscience. http://www.jneurosci.org/content/25/12/3032.full.pdf. 
  19. ^ Quinn JF, Raman R, Thomas RG, et al. (November 2010). "Docosahexaenoic acid supplementation and cognitive decline in Alzheimer disease: a randomized trial". JAMA 304 (17): 1903–11. doi:10.1001/jama.2010.1510. PMID 21045096. 
  20. ^ National Institute on Aging (July 16, 2007). "DHA Phase 3 trial in Alzheimer's disease". http://clinicaltrials.gov/ct/show/NCT00440050. Retrieved August 10, 2007. 
  21. ^ Karin Yurko-Mauroa, Deanna McCarthya, Dror Romb, Edward B. Nelsona, Alan S. Ryana, Andrew Blackwellc, Norman Salem Jr.a, Mary Stedman (03 May 2010). "Beneficial effects of docosahexaenoic acid on cognition in age-related cognitive decline". http://www.alzheimersanddementia.com/article/S1552-5260%2810%2900040-3/abstract. 
  22. ^ Matthew, Muldoon; Christopher M. Ryan, Lei Sheu, Jeffrey K. Yao, Sarah M. Conklin, and Stephen B. Manuck (January, 28). "Serum Phospholipid Docosahexaenonic Acid Is Associated with Cognitive Functioning during Middle Adulthood". Journal of Nutrition. http://jn.nutrition.org/content/early/2010/02/24/jn.109.119578.short. 
  23. ^ Kato T, Hancock RL, Mohammadpour H, McGregor B, Manalo P, Khaiboullina S, Hall MR, Pardini L, Pardini RS (2002). "Influence of omega-3 fatty acids on the growth of human colon carcinoma in nude mice". Cancer Lett. 187 (1-2): 169–77. doi:10.1016/S0304-3835(02)00432-9. PMID 12359365. 
  24. ^ Schønberg SA, Lundemo AG, Fladvad T, Holmgren K, Bremseth H, Nilsen A, Gederaas O, Tvedt KE, Egeberg KW, Krokan HE (2006). "Closely related colon cancer cell lines display different sensitivity to polyunsaturated fatty acids, accumulate different lipid classes and downregulate sterol regulatory element-binding protein 1". Cancer Lett. 273 (12): 2749–65. doi:10.1111/j.1742-4658.2006.05292.x. PMID 16817902. 
  25. ^ Shaikh IAA, Brown I, Schofield AC, Wahle KWJ, Heys SD (November 2008). "Docosahexaenoic acid enhances the efficacy of docetaxel in prostate cancer cells by modulation of apoptosis: the role of genes associated with the NF-kappaB pathway.". Prostate. 68 (15): 1635–1646. doi:10.1002/pros.20830. PMID 18668525. 
  26. ^ Elmesery ME, Algayyar MM, Salem HA, Darweish MM, El-Mowafy AM (April 2009). "Chemopreventive and renal protective effects for docosahexaenoic acid (DHA): implications of CRP and lipid peroxides". Cell Div 4 (1): 6. doi:10.1186/1747-1028-4-6 (inactive 2010-01-07). PMC 2680397. PMID 19341447. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2680397. 
  27. ^ . doi:10.1093/aje/kwr027. PMID 21518693. 
  28. ^ [1]
  29. ^ Beth Vincent, MHS (2005-10-31). "The Importance of DHA During Pregnancy and Breastfeeding". Archived from the original on 2007-11-17. http://web.archive.org/web/20071117084833/http://www.drlaura.com/sah/sahm.html?mode=view&tile=1&id=10576. Retrieved 2007-10-29. 
  30. ^ http://www.marchofdimes.com/aboutus/49267_55545.asp
  31. ^ Jennifer Denomme, Ken D. Stark, and Bruce J. Holub (August 20, 2004). "Directly Quantitated Dietary (n-3) Fatty Acid Intakes of Pregnant Canadian Women Are Lower than Current Dietary Recommendations". http://jn.nutrition.org/cgi/content/abstract/135/2/206. Retrieved October 9, 2007. 
  32. ^ DHASCO and ARASCO in Infant Formula - Food Standards
  33. ^ Harnam, F; F. Shahidi (May 2004). "Synthesis of structured lipids via acidolysis of docosahexaenoic acid single-cell oil (DHASCO) with capric acid.". J Agric Food Chem 52 (10): 2900–2906. doi:10.1021/jf035316f. PMID 15137833. http://www.ncbi.nlm.nih.gov/pubmed/15137833. 
  34. ^ Connell, Gary, J. et al. (2001-07-26). "SOLVENTLESS EXTRACTION PROCESS". http://www.wipo.int/ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=01/53512.010726&ELEMENT_SET=DECL. Retrieved February 8, 2006.  A patent at the WIPO.
  35. ^ Replacing Mother—Imitating Human Breast Milk in the Laboratory. The Cornucopia Institute. January 2008
  36. ^ Clandinin M, Van Aerde J, Merkel K, Harris C, Springer M, Hansen J, Diersen-Schade D (2005). "Growth and development of preterm infants fed infant formulas containing docosahexaenoic acid and arachidonic acid". J Pediatr 146 (4): 461–8. doi:10.1016/j.jpeds.2004.11.030. PMID 15812447. 
  37. ^ Ramakrishnan, Usha; et al. (8/01/11). "Prenatal Docosahexaenoic Acid Supplementation and Infant Morbidity: Randomized Controlled Trial". Journal of the American Academy of Pediatrics. doi:10.1542/peds.2010-1386. http://pediatrics.aappublications.org/content/early/2011/07/28/peds.2010-1386. 
  38. ^ Maria Makrides, “The Effects of DHA Supplementation During Pregnancy on Maternal Depression and Neurodevelopment of Young Children.” The Journal of American Medical Association http://jama.ama-assn.org/content/304/15/1675.abstract
  39. ^ Kelley DS et al. DHA supplementation decreases serum C-reactive protein and other markers of inflammation in hypertriglyceridemic men. J Nutr. 2009 Mar;139(3):495-501. Epub 2009 Jan 21.
  40. ^ Farzaneh-Far R et al. Association of Marine Omega-3 Fatty Acid Levels With Telomeric Aging in Patients With Coronary Heart DiseaseJAMA. 2010;303(3):250-257.
  41. ^ Aline Hittle. “DHA in Slowing the Progression of AD.” Baylor College of Medicine. http://www.bcm.edu/neurology/alzheimers/index.cfm?pmid=16413
  42. ^ “Kathleen Blanchard. “DHA in Fish Oil Could Protect from Stroke Disability.” Louisiana State University.
  43. ^ Jones, John. "Nutritional Products from Space Research". May 1st, 2001. NASA. http://www.sti.nasa.gov/tto/spinoff1996/42.html. 
  44. ^ "FDA: Why is there interest in adding DHA and ARA to infant formulas?". US Food & Drug Adminstration. http://www.fda.gov/Food/FoodSafety/Product-SpecificInformation/InfantFormula/ConsumerInformationAboutInfantFormula/ucm108558.htm. Retrieved July, 2002. 
  45. ^ "FDA Announces Qualified Health Claims for Omega-3 Fatty Acids". US Food & Drug Administration. 
  46. ^ Rivlin, Gary (2007-01-14). "Magical or Overrated? A Food Additive in a Swirl". The New York Times. http://www.nytimes.com/2007/01/14/business/yourmoney/14omega.html?_r=1. Retrieved 2007-01-15. 
  47. ^ Sanders, Thomas A.B. (August–September 2009). "DHA status of vegetarians". Prostaglandins, Leukotrienes, and Essential Fatty Acids (International Society for the Study of Fatty Acids and Lipids) 81 (2–3): 137–141. doi:10.1016/j.plefa.2009.05.013. ISSN 0952-3278. PMID 19500961. 
  48. ^ Vedin I, et al. (1 June 2008). "Effects of docosahexaenoic acid–rich n–3 fatty acid supplementation on cytokine release". Am J Clin Nutr 87 (6): 1616–1622. PMID 18541548. http://www.ajcn.org/cgi/content/abstract/87/6/1616. 
  49. ^ Crawford, M et al. (2000). "Evidence for the unique function of docosahexanoic acid (DHA) during the evolution of the modern hominid brain". Lipids 34 (S1): S39–S47. doi:10.1007/BF02562227. PMID 10419087. 
  50. ^ Carlson BA, Kingston JD (2007). "Docosahexaenoic acid biosynthesis and dietary contingency: Encephalization without aquatic constraint". Am. J. Hum. Biol. 19 (4): 585–8. doi:10.1002/ajhb.20683. PMID 17546613. 

External links

v · d · eLipids: fatty acids
Saturated
VFA: Acetic (C2) · Propionic (C3) · Butyric (C4) · Valeric (C5) · Caproic (C6) · Enanthic (C7) · Caprylic (C8) · Pelargonic (C9) · Capric (C10) · Undecylic (C11) · Lauric (C12) · Tridecylic (C13) · Myristic (C14) · Pentadecanoic (C15) · Palmitic (C16) · Margaric (C17) · Stearic (C18) · Nonadecylic (C19) · Arachidic (C20) · Heneicosylic (C21) · Behenic (C22) · Tricosylic (C23) · Lignoceric (C24) · Pentacosylic (C25) · Cerotic (C26) · Heptacosylic (C27) · Montanic (C28) · Nonacosylic (C29) · Melissic (C30) · Hentriacontylic (C31) · Lacceroic (C32) · Psyllic (C33) · Geddic (C34) · Ceroplastic (C35) · Hexatriacontylic (C36)
n−3 Unsaturated
α-Linolenic • Stearidonic • Eicosapentaenoic • Docosahexaenoic
n−6 Unsaturated
n−9 Unsaturated
biochemical families: prot · nucl · carb (glpr, alco, glys) · lipd (fata/i, phld, strd, gllp, eico) · amac/i · ncbs/i · ttpy/i

Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • docosahexaenoic acid — do·co·sa·hex·a·e·no·ic acid .dō kō sə .hek sə .ē .nō ik n an omega 3 fatty acid C22H32O2 found esp. in fish of cold waters abbr. DHA * * * do·co·sa·hexa·eno·ic ac·id (do ko″sə hek″sə e noґik) all cis 4,7,10,13,16,19… …   Medical dictionary

  • docosahexaenoic acid — noun an omega 3 fatty acid with 22 carbon atoms; found in fish (especially tuna and bluefish) • Hypernyms: ↑omega 3 fatty acid, ↑omega 3 * * * ˌdōkōsəˌheksəˌē¦nōik noun Etymology: International Scientific Vocabulary docosa (as in docosanoic acid) …   Useful english dictionary

  • docosahexaenoic acid — noun Etymology: International Scientific Vocabulary docosanoic acid (a crystalline fatty acid) + hexa + ene + oic an omega 3 fatty acid C22H32O2 found especially in fish of cold waters …   New Collegiate Dictionary

  • docosahexaenoic acid — an omega 3 fatty acid found in fish which protects ageing rodent brains from the clumping seen in Alzheimer s disease. This chemical is formed in microalgae of the genus Schizochytrium and concentrated up the food chain to fish and other… …   Dictionary of ichthyology

  • docosahexaenoic acid — noun An omega 3 fatty acid and essential fatty acid found in fish oils, metabolized to form the docosanoids. Syn: DHA, cervonic acid …   Wiktionary

  • docosahexaenoic acid — n. DHA, essential fatty acid which is important in the development of babies especially concerning their eyes and brain; omega 3 fatty acid found in tuna and bluefish …   English contemporary dictionary

  • docosahexaenoic acid — /dok euh seuh hek seuh i noh ik, dok /, Biochem. See DHA. [see DOCOSANOIC, HEXA ] * * * …   Universalium

  • docosahexaenoic — adjective Of or pertaining to docosahexaenoic acid or its derivatives …   Wiktionary

  • dervonic acid — docosahexaenoic acid …   Dictionary of ichthyology

  • Omega-3 fatty acid — For an explanation of n and numerical nomenclature (such as n−3 or 18:3), see Fatty acid#Nomenclature. Types of fats in food Unsaturated fat Monounsaturated fat Polyunsaturated fat Trans fat Cis fat Omega fatty acids: ω−3 ω−6 ω−9 Saturated fat… …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”