Alpha-linolenic acid

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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. 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. The other group of essential fatty acids is the omega-6 fatty acids, for example linoleic acid. Particularly rich food sources of Alpha-linolenic acid are chia and flaxseed. It is also found in various oils, namely mustard oil, flaxseed oil, canola (rapeseed) oil, soybean oil, pumpkin seed oil, perilla seed oil, and walnut oil. Various studies have shown that ALA is related to lower risk of cardiovascular disease. 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 and macular degeneration.

Research has also suggested a major neuroprotective effect of ALA in in-vivo models of both global ischemia and KA-induced epilepsy. PMID 10775263

Reduction of alpha-linolenic acid yields linolenyl alcohol.

The chemical strucuture of ALA showing physiological numbering (red) and chemical numbering (blue) conventions.

See also

• Gamma-linolenic acid
• Essential fatty acid

References