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Alpha-linolenic acid

Alpha-linolenic acid:Linolenic acid
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Linolenic acid

Alpha-linolenic acid (ALA) is a polyunsaturated omega-3 fatty acid with the molecular formula C18H30O2 and molar mass 278.43 g/mol. In physiological literature, it is given the name 18:3(n-3). Its systematic chemical name is all-cis-9,12,15-octadecatrienoic acid.[1] Chemically, ALA is a carboxylic acid with an 18-carbon chain and three cis double bonds; the first double bond is located at the third carbon from the omega end.

Alpha-linolenic acid is a member of the group of essential fatty acids called omega-3 fatty acids, so called because they are an essential dietary requirement for all mammals. Alpha linolenic acid is the main fatty acid in the thylakoid membranes of the green leaves of plants (the membranes responsible for photosynthesis).[citation needed] Greens, therefore, and animals that eat greens, are a good source of this omega-3 fat. Some seeds and seed oils are also rich in alpha linolenic acid, notably rapeseed, chia, flaxseed, hemp, walnuts, and soybeans, but most seeds and seed oils are much richer in the omega-6 fat linoleic acid. Linoleic acid is also an essential fat, but it, and the other omega-6 fats, compete with omega-3s for positions in cell membranes and have very different effects on human health. Studies have found evidence that ALA is related to a lower risk of cardiovascular disease.[2][3]

However, the mechanism is still unclear: The body converts ALA into the longer chain fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), and it is unknown whether the protective effect against cardiac arrhythmia is exerted by ALA itself, or by these metabolic products. Some studies have linked ALA with rapidly progressing prostate cancer[4] and macular degeneration.[5]

Research has also suggested a major neuroprotective effect of ALA in in-vivo models of both global ischemia and KA-induced epilepsy.[6]

Reduction of alpha-linolenic acid yields linolenyl alcohol.

Alpha-linolenic acid:The chemical strucuture of ALA showing physiological numbering (red) and chemical numbering (blue) conventions.
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The chemical strucuture of ALA showing physiological numbering (red) and chemical numbering (blue) conventions.



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References

  1. ^ Beare-Rogers (2001). IUPAC Lexicon of Lipid Nutrition (pdf). Retrieved on February 22 2006.
  2. ^ Penny M. Kris-Etherton, William S. Harris, [and] Lawrence J. Appel, for the Nutrition Committee (2002). "Fish Consumption, Fish Oil, Omega-3 Fatty Acids, and Cardiovascular Disease" (pdf). Circulation 106 (21): 2747-2757. DOI:10.1161/01.CIR.0000038493.65177.94. Retrieved on 25 July 2006. PMID 12438303
  3. ^ William E. Connor (2000). "Importance of n-3 fatty acids in health and disease" (pdf). American Journal of Clinical Nutrition 71 (1 Suppl.): 171S-5S. Retrieved on 25 July 2006. PMID 10617967
  4. ^ Brouwer IA, Katan MB, Zock PL (2004). "Dietary alpha-linolenic acid is associated with reduced risk of fatal coronary heart disease, but increased prostate cancer risk: a meta-analysis.". Journal of Nutrition 134 (4): 919-22. Retrieved on 13 November 2006. PMID 15051847
  5. ^ Eunyoung Cho, Shirley Hung, Walter C Willett, Donna Spiegelman, Eric B Rimm, Johanna M Seddon, Graham A Colditz and Susan E Hankinson (2001). "Polyunsaturated fatty acids are potent neuroprotectors". American Journal of Clinical Nutrition 73 (2): 209-218. Retrieved on 13 November 2006. PMID 11157315
  6. ^ Inger Lauritzen, Nicolas Blondeau, Catherine Heurteaux, Catherine Widmann, Georges Romey and Michel Lazdunski (2000). "Polyunsaturated fatty acids are potent neuroprotectors". The EMBO Journal 19 (8): 1784-1793. Retrieved on 6 October 2005. PMID 10775263

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Articles with unsourced statements | Fatty acids | Essential fatty acids | Essential nutrients

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