Linoleic acid 880497 223636539 2008-07-05T00:33:56Z Quarknimble 7397263 /* Foods */ {{Chembox new | Name = '''Linoleic acid''' | ImageFile = LAnumbering.png | ImageSize = 375px | IUPACName = ''cis, cis''-9,12-octadecadienoic acid.<ref>{{cite web|author=Beare-Rogers|title=IUPAC Lexicon of Lipid Nutrition| year=2001| url=http://www.iupac.org/publications/pac/2001/pdf/7304x0685.pdf| accessdate=2006-02-22| format=pdf}}</ref> | Section1 = {{Chembox Identifiers | CASNo = {{{CAS|60-33-3}}} | SMILES = CCCCCC=CCC=CCCCCCCCC(=O)O }} | Section2 = {{Chembox Properties | Formula = C<sub>18</sub>H<sub>32</sub>O<sub>2</sub> | MolarMass = [[List of elements by atomic mass|280.44548(1724)]] g/[[Mole (unit)|mol]] | Density = 0.9 g/cm<sup>3</sup> | MeltingPt = -5 °C | BoilingPt = °C }} }} '''Linoleic acid''' (LA) is an unsaturated [[omega-6 fatty acid]]. It is a colorless liquid. In physiological literature, it is called 18:2(n-6). Chemically, linoleic acid is a [[carboxylic acid]] with an 18-carbon chain and two ''[[cis]]'' double bonds; the first double bond is located at the sixth carbon from the omega end. The word ''linoleic'' comes from the [[Greek language|Greek]] word ''linon'' ([[flax]]). ''Oleic'' means ''of, relating to, or derived from oil'' or ''of or relating to [[oleic acid]]'' since removing the omega-6 double bond produces oleic acid. ==In Physiology== Linoleic acid is a [[polyunsaturated]] [[fatty acid]] used in the biosynthesis of [[prostaglandin]]s. It is found in the lipids of [[cell membrane]]s. It is abundant in many [[vegetable oil]]s, especially [[safflower]] and [[sunflower]] oils. To be fully utilised by the body, LA must be converted into [[gamma-linolenic acid]], a reaction catalysed by the [[enzyme]] [[desaturase|delta-6-desaturase]] (D6D). Linoleic acid is a member of the group of [[essential fatty acids]] called [[omega-6 fatty acid]]s, so called because they are an essential dietary requirement for all mammals. The other group of essential fatty acids is the [[omega-3 fatty acid]]s, for example [[Alpha-linolenic acid]]. Omega-6 deficiency symptoms include dry hair, hair loss,<ref name=Cunnane>{{cite journal |author=Cunnane S, Anderson M |title=Pure linoleate deficiency in the rat: influence on growth, accumulation of n-6 polyunsaturates, and (1-<sup>14</sup>C) linoleate oxidation |journal=J Lipid Res |volume=38 |issue=4 |pages=805–12 |year=1997 |pmid=9144095| url = http://www.jlr.org/cgi/reprint/38/4/805 |accessdate=2007-01-15}}</ref> and poor wound healing.<ref name=Ruthig>{{cite journal|author=Ruthig DJ & Meckling-Gill KA.|year=1999 | title=Both (n-3) and (n-6) fatty acids stimulate wound healing in the rat intestinal epithelial cell line, IEC-6|journal= Journal of Nutrition|volume=129|issue=10|pages=1791–8| pmid= 10498749 |accessdate=2007-01-15 |url=http://jn.nutrition.org/cgi/content/full/129/10/1791}}</ref> It is easy to meet the daily requirement for these fatty acids (even for people consuming low fat diets) and most people get plenty of omega-6 fatty acids in their diet by consuming approximately a tablespoon of polyunsaturated plant oils per day.{{Fact|date=February 2007}}<!--I know it's true, but we need a cite. Especially since there is no RDA on fatty acids --> ==Industrial uses== Linoleic acid is used in making [[soap]]s, [[emulsifier]]s, and quick-drying oils. Reduction of linoleic acid yields [[linoleyl alcohol]]. Linoleic acid has become increasingly popular in the beauty products industry because of its beneficial properties on the skin. Research points to linoleic acid's affective properties when applied topically on the skin, ie. anti-inflammatory, acne reduction, moisture retention properties.<ref>{{cite journal | coauthors = Diezel W.E., Schulz E., Skanks M., Heise H. | year = 1993 | title = Plant oils: Topical application and anti-inflammatory effects (croton oil test) | journal = Dermatol. Monatsschr | volume = 179 | pages = 173}}</ref><ref>{{cite journal | coauthors = Letawe C, Boone M, Pierard GE | year = 1998 | month = March | title = Digital image analysis of the effect of topically applied linoleic acid on acne microcomedones | journal = Clinical & Experimental Dermatology | volume = 23 | issue = 2 | pages = 56–58| pmid = : 9692305 | url = http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=9692305&itool=iconabstr&query_hl=17&itool=pubmed_docsum | doi = 10.1046/j.1365-2230.1998.00315.x | author = Letawe,}}</ref><ref>{{cite journal | coauthors=Darmstadt GL, Mao-Qiang M, Chi E, Saha SK, Ziboh VA, Black RE, Santosham M, Elias PM |year=2002|title=Impact of topical oils on the skin barrier: possible implications for neonatal health in developing countries |journal=Acta Paediatrica |volume=91 |issue=5 |pages=546–554 |accessdate=2007-01-12|doi=10.1080/080352502753711678|author=Darmstadt, G L}}</ref> Noni seed oil is abundant in linoleic acid, and a number of beauty products contain noni seed oil.{{Fact|date=December 2007}} ==Foods== Oils and foods that contain linoleic acid include [[safflower oil]] (78%), [[poppy seed oil]] (70%), [[hemp oil]] (50-70%), [[walnut oil]], grass fed cow milk, [[olive oil]], [[palm oil]], [[sunflower oil]], [[soybean]], [[lard]], [[coconut oil]], [[egg yolks]] (16%), [[spirulina]], [[peanut oil]], [[okra]], [[rice bran oil]], [[wheat germ oil]], [[grape seed oil]], [[macadamia oil]], [[pistachio oil]], [[sesame oil]]. ==See also== *[[Alpha-linolenic acid]] *[[Conjugated linoleic acid]] *[[Essential fatty acids]] *[[Essential fatty acid interactions]] *[[Eicosanoid]]s *[[Essential nutrient]]s *[[Linolein]] ==References== {{Reflist|2}} {{Fatty acids}} [[Category:Carboxylic acids]] [[Category:Essential fatty acids]] [[Category:Essential nutrients]] [[Category:Fatty acids]] [[ar:حمض زيت الكتان]] [[cs:Kyselina linolová]] [[de:Linolsäure]] [[es:Ácido linoleico]] [[fr:Acide linoléique]] [[lv:Linolskābe]] [[nl:Linolzuur]] [[ja:リノール酸]] [[pl:Kwas linolowy]] [[pt:Ácido linoléico]] [[ru:Линолевая кислота]] [[fi:Linolihappo]] [[sv:Linolsyra]]