linoleic acid

{{Distinguish|linolenic acid|alpha-linolenic acid|lipoic acid|linolelaidic acid}}

{{chembox

| Watchedfields = changed

| verifiedrevid = 476999843

| Name = Linoleic acid

| ImageFile = LAnumbering.png

| ImageSize = 300px

| ImageFile1 = Linoleic-acid-from-xtal-1979-3D-balls.png

| ImageSize1 = 300px

| ImageFile2 = Linoleic-acid-from-xtal-1979-3D-vdW.png

| ImageSize2 = 300px

| PIN = (9Z,12Z)-Octadeca-9,12-dienoic acid

| OtherNames = cis,cis-9,12-Octadecadienoic acid
C18:2 (Lipid numbers)

| Section1 = {{Chembox Identifiers

| IUPHAR_ligand = 1052

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 4444105

| UNII_Ref = {{fdacite|correct|FDA}}

| KEGG_Ref = {{keggcite|correct|kegg}}

| KEGG = C01595

| Gmelin = 57557

| Beilstein = 1727101

| PubChem = 5280450

| EC_number = 200-470-9

| DrugBank = DB14104

| 3DMet = B00328

| UNII = 9KJL21T0QJ

| InChI = 1/C18H32O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18(19)20/h6-7,9-10H,2-5,8,11-17H2,1H3,(H,19,20)/b7-6-,10-9-

| InChIKey = OYHQOLUKZRVURQ-HZJYTTRNBX

| ChEMBL_Ref = {{ebicite|correct|EBI}}

| ChEMBL = 267476

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/C18H32O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18(19)20/h6-7,9-10H,2-5,8,11-17H2,1H3,(H,19,20)/b7-6-,10-9-

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = OYHQOLUKZRVURQ-HZJYTTRNSA-N

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo = 60-33-3

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI = 17351

| SMILES = CCCCC/C=C\C/C=C\CCCCCCCC(=O)O

}}

| Section2 = {{Chembox Properties

| C=18 | H=32 | O=2

| Appearance = Colorless oil

| Density = 0.9 g/cm³The Merck Index, 11th Edition, 5382

| MeltingPt = {{convert|-12|C|F}}
{{convert|-6.9|C|F}}{{cite book | author=William M. Haynes | title=CRC Handbook of Chemistry and Physics | edition=97th | year=2016 | publisher=CRC Press | location=Boca Raton | isbn=978-1-4987-5429-3 | pages=3–338 | url=https://books.google.com/books?id=VVezDAAAQBAJ}}
{{convert|-5|C|F}}{{GESTIS|ZVG=14230|CAS=60-33-3}}

| BoilingPt = {{convert|229|C|F}} at 16 mmHg
{{convert|230|C|F}} at 21 mbar
{{convert|230|C|F}} at 16 mmHg

| Solubility = 0.139 mg/L

| VaporPressure = 16 Torr at 229 °C{{Citation needed|date=June 2011}}

| pKa = 4.77 at 25°CNational Center for Biotechnology Information (2024). PubChem Compound Summary for CID 5280450, Linoleic Acid. Retrieved January 20, 2024 from https://pubchem.ncbi.nlm.nih.gov/compound/Linoleic-Acid.

}}

| Section3 = {{Chembox Hazards

| NFPA-H = 2

| NFPA-F = 1

| NFPA-R = 0

| MainHazards =

| FlashPt = {{convert|112|C|F}}

| AutoignitionPt = }}

| Section4 =

| Section5 =

| Section6 =

}}

Linoleic acid (LA) is an organic compound with the formula {{chem2|HOOC(CH2)7CH\dCHCH2CH\dCH(CH2)4CH3}}. Both alkene groups ({{chem2|\sCH\dCH\s}}) are cis. It is a fatty acid sometimes denoted 18:2 (n−6) or 18:2 cis-9,12. A linoleate is a salt or ester of this acid.{{cite web|url=http://www.cyberlipid.org/fa/acid0001.htm|title=Fatty Acids|publisher=Cyber Lipid|access-date=31 July 2017|archive-url=https://web.archive.org/web/20181028011853/http://www.cyberlipid.org/fa/acid0001.htm|archive-date=28 October 2018|url-status=dead}}

Linoleic acid is a polyunsaturated, omega−6 fatty acid. It is a colorless liquid that is virtually insoluble in water but soluble in many organic solvents. It typically occurs in nature as a triglyceride (ester of glycerin) rather than as a free fatty acid.{{cite journal| pmc=2843518 | pmid=19400700 | doi=10.1146/annurev-nutr-080508-141108 | volume=29 | title=Is there a fatty acid taste? | year=2009 | journal=Annual Review of Nutrition | pages=305–327 | last1=Mattes | first1=Richard D.}} It is one of two essential fatty acids for humans, who must obtain it through their diet,{{cite journal |title=The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases |author=Simopoulos, Artemis P. |author-link=Artemis Simopoulos |journal=Experimental Biology and Medicine |year=2008 |volume=233 |issue=6 |pages=674–688 |doi=10.3181/0711-mr-311 | pmid=18408140 |s2cid=9044197}} and the most essential, because the body uses it as a base to make the others.

The word "linoleic" derives {{ety|la|linum|flax||oleum|oil}}, reflecting the fact that it was first isolated from linseed oil.

History

In 1844, F. Sacc, working at the laboratory of Justus von Liebig, isolated linoleic acid from linseed oil. In 1886, K. Peters determined the existence of two double bonds.{{cite journal |title=Über Leinölsäure |last=Peters |first=Karl |date=December 1886 |journal=Monatshefte für Chemie und verwandte Teile anderer Wissenschaften |volume=7 |pages=552–555 |url=https://archive.org/details/sim_monatshefte-fuer-chemie_1886_7_contents/page/554/mode/1up |doi=10.1007/BF01516597}} Its essential role in human diet was discovered by G. O. Burr and others in 1930. Its chemical structure was determined by T. P. Hilditch and others in 1939, and it was synthesized by R. A. Raphael and F. Sondheimer in 1950.

In physiology

The consumption of linoleic acid is vital to proper health, as it is an essential fatty acid.{{cite journal |last1=Whelan |first1=Jay |last2=Fritsche |first2=Kevin |title=Linoleic Acid |journal=Advances in Nutrition |date=May 2013 |volume=4 |issue=3 |pages=311–312 |doi=10.3945/an.113.003772|pmc=3650500 |pmid=23674797}}

=Metabolism and eicosanoids=

File:Linoleic Acid Metabolism.gif{{clear left}}

Linoleic acid (LA: {{chem|C|18|H|32|O|2}}; 18:2,n−6) is a precursor to arachidonic acid (AA: {{chem|C|20|H|32|O|2}}; 20:4,n−6) with elongation and unsaturation.{{r|Whelan & Fritsche}} AA is the precursor to some prostaglandins,{{cite journal |pmid=4723909 |date=25 August 1973 |last1=Wlodawer |first1=Paulina |last2=Samuelsson |first2=Bengt |author-link2=Bengt I. Samuelsson |title=On the organization and mechanism of prostaglandin synthetase |journal=The Journal of Biological Chemistry |volume=248 |issue=16 |pages=5673–5678 |doi=10.1016/S0021-9258(19)43558-8 |doi-access=free}} leukotrienes (LTA, LTB, LTC), thromboxane (TXA){{cite journal |last1=Terano |first1=Takashi |last2=Salmon |first2=John A. |last3=Moncada |first3=Salvador |date=February 1984 |title=Biosynthesis and biological activity of leukotriene B5 |journal=Prostaglandins |volume=27 |issue=2 |pages=217–232 |doi=10.1016/0090-6980(84)90075-3 |pmid=6326200}} and the N-acylethanolamine (NAE) arachidonoylethanolamine (AEA: {{chem|C|22|H|37|NO|2}}; 20:4,n−6),{{Cite journal |last1=Murru |first1=Elisabetta |last2=Lopes |first2=Paula A. |last3=Carta |first3=Gianfranca |last4=Manca |first4=Claudia |last5=Abolghasemi |first5=Armita |last6=Guil-Guerrero |first6=José L. |last7=Prates |first7=José A. M. |last8=Banni |first8=Sebastiano |date=2021-02-15 |title=Different Dietary N-3 Polyunsaturated Fatty Acid Formulations Distinctively Modify Tissue Fatty Acid and N-Acylethanolamine Profiles |journal=Nutrients |language=en |volume=13 |issue=2 |pages=625 |doi=10.3390/nu13020625 |pmid=33671938 |pmc=7919039 |issn=2072-6643|doi-access=free }} and other endocannabinoids and eicosanoids.{{Cite journal |last1=Salem |first1=Norman |last2=Van Dael |first2=Peter |date=2020-02-27 |title=Arachidonic Acid in Human Milk |journal=Nutrients |language=en |volume=12 |issue=3 |pages=626 |doi=10.3390/nu12030626 |pmid=32121018 |pmc=7146261 |issn=2072-6643|doi-access=free }}

The metabolism of LA to AA begins with the conversion of LA into gamma-linolenic acid (GLA), effected by Δ6 desaturase.Evidence suggests that infants must acquire Δ6-desaturase breast milk. Breast-milk fed babies have higher concentrations of GLA than formula-fed babies, while formula-fed babies have elevated concentrations of LA. {{cite journal | author = David F. Horrobin | year = 1993 | title = Fatty acid metabolism in health and disease: the role of Δ-6-desaturase | journal = American Journal of Clinical Nutrition | volume = 57 | issue = 5 Suppl | pages = 732S–737S| doi = 10.1093/ajcn/57.5.732S | pmid = 8386433 | doi-access = free }} GLA is converted to dihomo-γ-linolenic acid (DGLA), the immediate precursor to AA.

LA is also converted by various lipoxygenases, cyclooxygenases, cytochrome P450 enzymes (the CYP monooxygenases), and non-enzymatic autoxidation mechanisms to mono-hydroxyl products viz., 13-Hydroxyoctadecadienoic acid, and 9-Hydroxyoctadecadienoic acid; these two hydroxy metabolites are enzymatically oxidized to their keto metabolites, 13-oxo-octadecadienoic acid and 9-oxo-octadecdienoic acid. Certain cytochrome P450 enzymes, the CYP epoxygenases, catalyze oxidation of LA to epoxide products viz., its 12,13-epoxide, vernolic acid, and its 9,10-epoxide, coronaric acid. These linoleic acid products are implicated in human physiology and pathology.{{Cite journal|last=Jandacek|first=Ronald J.|date=2017-05-20|title=Linoleic Acid: A Nutritional Quandary|journal=Healthcare|volume=5|issue=2|page=25|doi=10.3390/healthcare5020025|issn=2227-9032|pmc=5492028|pmid=28531128|doi-access=free}}

Hydroperoxides derived from the metabolism of anandamide (AEA: {{chem|C|22|H|37|NO|2}}; 20:4,n−6), or its linoleoyl analogues, are by a lipoxygenase action found to be competitive inhibitors of brain and immune cell FAAH, the enzyme that breaks down AEA and other endocannabinoids, and the compound linoleoyl-ethanol-amide ({{chem|C|20|H|37|NO|2}}; 18:2,n−6), an N-acylethanolamine,{{clarify|reason=Style of this sentence makes it incomprehensible to the reader. It needs to be reworded.|date=February 2023}} - the ethanolamide of linoleic acid (LA: {{chem|C|18|H|32|O|2}}; 18:2,n−6) and its metabolized incorporated ethanolamine (MEA: {{chem|C|2|H|7|NO}}),{{Cite web |last=PubChem |title=Linoleoyl ethanolamide |url=https://pubchem.ncbi.nlm.nih.gov/compound/5283446 |access-date=2022-10-29 |website=pubchem.ncbi.nlm.nih.gov |language=en}} is the first natural inhibitor of FAAH, discovered.{{Cite journal |last1=Maccarrone |first1=Mauro |last2=Stelt |first2=Marcelis van der |last3=Rossi |first3=Antonello |last4=Veldink |first4=Gerrit A. |last5=Vliegenthart |first5=Johannes F. G. |last6=Agrò |first6=Alessandro Finazzi |date=1998-11-27 |title=Anandamide Hydrolysis by Human Cells in Culture and Brain * |url=https://www.jbc.org/article/S0021-9258(19)59084-6/abstract |journal=Journal of Biological Chemistry |language=English |volume=273 |issue=48 |pages=32332–32339 |doi=10.1074/jbc.273.48.32332 |issn=0021-9258 |pmid=9822713 |doi-access=free |hdl=1887/50863 |hdl-access=free }}{{Cite journal |last1=Scala |first1=Coralie Di |last2=Fantini |first2=Jacques |last3=Yahi |first3=Nouara |last4=Barrantes |first4=Francisco J. |last5=Chahinian |first5=Henri |date=2018-05-22 |title=Anandamide Revisited: How Cholesterol and Ceramides Control Receptor-Dependent and Receptor-Independent Signal Transmission Pathways of a Lipid Neurotransmitter |journal=Biomolecules |volume=8 |issue=2 |pages=31 |doi=10.3390/biom8020031 |issn=2218-273X |pmc=6022874 |pmid=29789479|doi-access=free }}

Uses and reactions

Linoleic acid is a component of quick-drying oils, which are useful in oil paints and varnishes. These applications exploit the lability of the doubly allylic {{chem2|C\sH}} groups ({{chem2|\sCH\dCH\sCH2\sCH\dCH\s}}) toward oxygen in air (autoxidation). Addition of oxygen leads to crosslinking and formation of a stable film.{{Ullmann|author=Ulrich Poth|title=Drying Oils and Related Products|year=2002|doi=10.1002/14356007.a09_055}}

Reduction of the carboxylic acid group of linoleic acid yields linoleyl alcohol.{{cite journal|first1=Homer|last1=Adkins|first2=R.H.|last2=Gillespie|doi=10.15227/orgsyn.029.0080|title=Oleyl Alcohol|journal=Organic Syntheses|year=1949|volume=29|page=80}}

Linoleic acid is a surfactant with a critical micelle concentration of 1.5 x 10⁻⁴ M @ pH 7.5.{{Citation needed|date=February 2021}}

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 anti-inflammatory, acne reductive, skin-lightening and moisture retentive properties when applied topically on the skin.{{cite journal

|last1=Diezel |first1=W.E.

|last2=Schulz |first2=E.

|last3=Skanks |first3=M.

|last4=Heise |first4=H.

| year=1993 |title=Plant oils: Topical application and anti-inflammatory effects (croton oil test) |journal=Dermatologische Monatsschrift |volume=179 |page=173}}{{cite journal

|last1=Letawe |first1=C.

|last2=Boone |first2=M.

|last3=Pierard |first3=G.E.

|date=March 1998 |title=Digital image analysis of the effect of topically applied linoleic acid on acne microcomedones |journal=Clinical and Experimental Dermatology |volume=23 |issue=2 |pages=56–58 |pmid=9692305 |doi=10.1046/j.1365-2230.1998.00315.x|s2cid=28594076}}{{cite journal

|last1=Ando |first1=Hideya

|last2=Ryu |first2=Atsuko

|last3=Hashimoto |first3=Akira

|last4=Oka |first4=Masahiro

|last5=Ichihashi |first5=Masamitsu

|date=March 1998 |title=Linoleic acid and α-linolenic acid lightens ultraviolet-induced hyperpigmentation of the skin |journal=Archives of Dermatological Research |volume=290 |issue=7 |pages=375–381 |pmid=9749992 |doi=10.1007/s004030050320|s2cid=23036319}}{{cite journal

|last1=Darmstadt |first1=Gary L.

|last2=Mao-Qiang |first2=M.

|last3=Chi |first3=E.

|last4=Saha |first4=S.K.

|last5=Ziboh |first5=V.A.

|last6=Black |first6=R.E.

|last7=Santosham |first7=M.

|last8=Elias |first8=P.M.

|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 |doi=10.1080/080352502753711678 |pmid=12113324 |citeseerx=10.1.1.475.1064}}

Linoleic acid is also used in some bar of soap products.

Dietary sources

It is abundant in safflower, and corn oil, and comprises over half their composition by weight. It is present in medium quantities in soybean oils, sesame, and almonds.{{cite web|year=2007 |work=USDA National Nutrient Database for Standard Reference, Release 20 |url=http://www.ars.usda.gov/ba/bhnrc/ndl |title=Nutrient Data Laboratory Home Page |publisher=U.S. Department of Agriculture, Agricultural Research Service |url-status=dead |archive-url=https://web.archive.org/web/20160414070404/http://www.ars.usda.gov/ba/bhnrc/ndl |archive-date=14 April 2016 }}{{cite journal |last1=Kaur |first1=Narinder |last2=Chugh |first2=Vishal |last3=Gupta |first3=Anil K. |title=Essential fatty acids as functional components of foods- a review |journal=Journal of Food Science and Technology |date=October 2014 |volume=51 |issue=10 |pages=2289–2303 |doi=10.1007/s13197-012-0677-0 |pmid=25328170 |pmc=4190204 }}

\|Name\|\|% LA^†\|\|ref.
class="wikitable sortable"
Salicornia oil	75%	{{cite journal \|title=Salicornia bigelovii, S. brachiata and S. herbacea: Their Nutritional Characteristics and an Evaluation of Their Potential as Salt Substitutes \|last=Alfheeaid \|first=Hani A. \|display-authors=etal \|date=November 2022 \|journal=Foods \|volume=11 \|issue=21 \|page=3402 \|doi=10.3390/foods11213402 \|doi-access=free \|pmc=9655280 \|pmid=36360016}}
Safflower oil	72–78%	{{cite book \|last1=Hall III \|first1=C. \|editor1-last=Wrigley \|editor1-first=Colin W. \|editor2-last=Corke \|editor2-first=Harold \|editor3-last=Seetharaman \|editor3-first=Koushik \|editor4-last=Faubion \|editor4-first=Jonathan \|title=Encyclopedia of Food Grains \|year=2015 \|publisher=Academic Press \|isbn=978-0-12-394786-4 \|url=https://books.google.com/books?id=ce7tBgAAQBAJ&pg=PA255}}
Evening Primrose oil	65–80%	{{cite web \|url=https://www.oilswelove.com/single-post/Evening-Primrose-Oil-for-Menopause-does-it-help \|title=Evening Primrose Oil for Menopause does it help \|date=2018-01-26 }}
Melon seed oil	50–70%	{{cite journal \|title=Comparative extraction of melon seed (Cucumis melo L.) oil by conventional and enzymatic methods: Physicochemical properties and oxidative stability \|vauthors=Zhang G, Li Z, Guo Z, Charalampopoulos D \|date=June 2024 \|journal=Journal of Agriculture and Food Research \|volume=16 \|doi=10.1016/j.jafr.2024.101182 \|doi-access=free}}
Poppyseed oil	74%	{{cite journal \|title=Chemical composition and oxidative stability of flax, safflower and poppy seed and seed oils \|last1=Bozan \|first1=Berrin \|last2=Temelli \|first2=Feral \|date=September 2008 \|journal=Bioresource Technology \|volume=99 \|issue=14 \|pages=6354–6359 \|doi=10.1016/j.biortech.2007.12.009\|pmid=18198133 \|bibcode=2008BiTec..99.6354B }}
Grape seed oil	70%	{{cite journal \|title=Grape (Vitis vinifera L.) Seed Oil: A Functional Food from the Winemaking Industry \|vauthors=Martin ME, Grao-Cruces E, Millan-Linares MC, Montserrat-de la Paz S \|date=October 2020 \|journal=Foods \|volume=9 \|issue=10 \|page=1360 \|doi=10.3390/foods9101360 \|doi-access=free \|pmc=7599587 \|pmid=32992712}}
Prickly Pear seed oil	50–78%	{{cite journal \|title=Prickly Pear Seed Oil Extraction, Chemical Characterization and Potential Health Benefits \|vauthors=Al-Naqeb G, Fiori L, Ciolli M, Aprea E \|date=August 2021 \|journal=Molecules \|volume=26 \|issue=16 \|page=5018 \|doi=10.3390/molecules26165018 \|doi-access=free \|pmc=8401162 \|pmid=34443606}}
Cardoon oil	60%	{{cite journal \|title=Chemical and Biological Evaluation of the Oil and Seedcake from Seeds of a Greek Cardoon Cultivar as Potential Functional Vegetable Oil. Comparison with Sesame, Flaxseed and Extra Virgin Olive Oils \|vauthors=Varvouni EF, Graikou K, Gortzi O, Cheilari A, Aligiannis N, Chinou I \|date=November 2021 \|journal=Foods \|volume=10 \|issue=11 \|page=2665 \|doi=10.3390/foods10112665 \|doi-access=free \|pmc=8618587 \|pmid=34828945}}{{cite journal \|title=A New Insight on Cardoon: Exploring New Uses besides Cheese Making with a View to Zero Waste \|vauthors=Barbosa CH, Andrade MA, Vilarinho F, Castanheira I, Fernando AL, Loizzo MR, Sanches Silva A \|date=May 2020 \|journal=Foods \|volume=9 \|issue=5 \|page=564 \|doi=10.3390/foods9050564 \|doi-access=free \|pmid=32370268 \|pmc=7278730 \|hdl=10316/106089 \|hdl-access=free }}
Hemp oil	54.3%	{{Cite journal\|last1=Oomah\|first1=B. Dave\|last2=Busson\|first2=Muriel\|last3=Godfrey\|first3=David V\|last4=Drover\|first4=John C. G.\|date=2002-01-01\|title=Characteristics of hemp (Cannabis sativa L.) seed oil\|journal=Food Chemistry\|volume=76\|issue=1\|pages=33–43\|doi=10.1016/S0308-8146(01)00245-X}}
Wheat germ oil	56%	{{cite journal \|title=Essential Components from Plant Source Oils: A Review on Extraction, Detection, Identification, and Quantification \|vauthors=Rahim MA \|display-authors=etal \|date=October 2023 \|journal=Molecules \|volume=28 \|issue=19 \|page=6881 \|doi=10.3390/molecules28196881 \|doi-access=free \|pmc=10574037 \|pmid=37836725}}{{cite journal \|title=Wheat germ oil: a comprehensive review \|last=Siraj \|first=Naila \|date=March 2022 \|journal=Food Science and Technology \|volume=42 \|doi=10.1590/fst.113721 \|doi-access=free}}
Cottonseed oil	54%	{{cite journal \|title=The evaluation of oil and fatty acid composition in seed of cotton accessions from various countries \|vauthors=Lukonge E, Labuschagne MT, Hugo A \|date=January 2007 \|journal=J Sci Food Agric \|volume=87 \|issue=2 \|pages=340–347 \|url=https://scholar.google.com/scholar_lookup?&title=The%20evaluation%20of%20oil%20and%20fatty%20acid%20composition%20in%20seed%20of%20cotton%20accessions%20from%20various%20countries&journal=J%20Sci%20Food%20Agr&doi=10.1002%2Fjsfa.2731&volume=87&pages=340-347&publication_year=2007&author=Lukonge%2CE&author=Labuschagne%2CMT&author=Hugo%2CA#d=gs_qabs&t=1722117655066&u=%23p%3DMfUD-Yo-ZBoJ \|doi=10.1002/jsfa.2731\|bibcode=2007JSFA...87..340L }} To download the article, click the title (not doi) and choose option [PDF] academia.edu.{{cite journal \|title=Effects of Dietary Cottonseed Oil and Cottonseed Meal Supplementation on Liver Lipid Content, Fatty Acid Profile and Hepatic Function in Laying Hens \|vauthors=Yang A \|display-authors=etal \|date=January 2021 \|journal=Animals \|volume=11 \|issue=1 \|page=78 \|doi=10.3390/ani11010078 \|doi-access=free \|pmc=7824706 \|pmid=33406775}}
Corn oil	51.9%	{{cite web \|url=https://fdc.nal.usda.gov/fdc-app.html#/food-details/748323/nutrients \|title=Oil, corn \|date=December 2019 \|website=FoodData Central \|publisher=USDA \|access-date=6 April 2022 \|archive-date=3 April 2019 \|archive-url=https://web.archive.org/web/20190403171801/https://fdc.nal.usda.gov/fdc-app.html#/food-details/748323/nutrients \|url-status=dead }}
Walnut oil	50–72%	{{cite journal \|title=An Overview on Traditional vs. Green Technology of Extraction Methods for Producing High Quality Walnut Oil \|vauthors=Masoodi L \|display-authors=etal \|date=September 2022 \|journal=Agronomy \|volume=12 \|issue=10 \|page=2258 \|doi=10.3390/agronomy12102258 \|doi-access=free}}{{cite web \|url=https://fdc.nal.usda.gov/fdc-app.html#/food-details/171030/nutrients \|title=Oil, walnut \|date=April 2019 \|website=FoodData Central \|publisher=USDA \|access-date=31 July 2024 \|archive-date=3 April 2019 \|archive-url=https://web.archive.org/web/20190403171801/https://fdc.nal.usda.gov/fdc-app.html#/food-details/171030/nutrients \|url-status=dead }}
Soybean oil	50.9%	{{cite web \|url=https://fdc.nal.usda.gov/fdc-app.html#/food-details/748366/nutrients \|title=Oil, soybean \|date=December 2019 \|website=FoodData Central \|publisher=USDA \|access-date=6 April 2022 \|archive-date=3 April 2019 \|archive-url=https://web.archive.org/web/20190403171801/https://fdc.nal.usda.gov/fdc-app.html#/food-details/748366/nutrients \|url-status=dead }}
Sesame oil	45%	{{cite web \|url=https://extension.okstate.edu/fact-sheets/sesame-seed-oil-properties.html \|title=Sesame Seed Oil Properties \|last=Dunford \|first=Nurhan \|date=August 2021 \|website=OSU Extension \|access-date=1 August 2024}}{{cite journal \|title=Physicochemical, potential nutritional, antioxidant and health properties of sesame seed oil: a review \|vauthors=Oboulbiga EB \|display-authors=etal \|date=June 2023 \|journal=Front. Nutr. \|volume=10 \|at=Table 2 \|doi=10.3389/fnut.2023.1127926 \|doi-access=free \|pmc=10292629 \|pmid=37377483}}
Pumpkin seed oil	42–59%	{{cite journal\|vauthors=Nawirska-Olszańska A, Kita A, Biesiada A, Sokół-Łętowska A, Kucharska AZ\|year=2013\|title=Characteristics of antioxidant activity and composition of pumpkin seed oils in 12 cultivars\|journal=Food Chemistry\|volume=139\|issue=1–4\|pages=155–161\|doi=10.1016/j.foodchem.2013.02.009\|pmid=23561092}}
Rice bran oil	39%
Argan oil	37%
Pistachio oil	32.7%
Peach oil	29%	{{cite journal \|title=Essential oil extracted from peach (Prunus persica) kernel and its physicochemical and antioxidant properties \| doi=10.1016/j.lwt.2011.05.012 \| volume=44 \|issue=10 \|journal=LWT - Food Science and Technology \|pages=2032–2039\|year=2011 \|last1=Wu \|first1=Hao \|last2=Shi \|first2=John \|last3=Xue \|first3=Sophia \|last4=Kakuda \|first4=Yukio \|last5=Wang \|first5=Dongfeng \|last6=Jiang \|first6=Yueming \|last7=Ye \|first7=Xingqian \|last8=Li \|first8=Yanjun \|last9=Subramanian \|first9=Jayasankar }}
Almonds	24%
Canola oil	17.8%	{{cite web \|url=https://fdc.nal.usda.gov/fdc-app.html#/food-details/748278/nutrients \|title=Oil, canola \|date=December 2019 \|website=FoodData Central \|publisher=USDA \|access-date=6 April 2022 \|archive-date=3 April 2019 \|archive-url=https://web.archive.org/web/20190403171801/https://fdc.nal.usda.gov/fdc-app.html#/food-details/748278/nutrients \|url-status=dead }}
Sunflower oil	20.5%	{{cite web \|url=https://fdc.nal.usda.gov/fdc-app.html#/food-details/1750349/nutrients \|title=Oil, sunflower \|date=April 2021 \|website=FoodData Central \|publisher=USDA \|access-date=6 April 2022 \|archive-date=3 April 2019 \|archive-url=https://web.archive.org/web/20190403171801/https://fdc.nal.usda.gov/fdc-app.html#/food-details/1750349/nutrients \|url-status=dead }}
Chicken fat	18–23%	{{cite journal \| title = The chemical composition of depot fats in chickens and turkeys \| vauthors = Nutter MK, Lockhart EE, Harris RS \| year = 1943 \| journal = Journal of the American Oil Chemists' Society \| volume = 20 \| issue = 11 \| pages = 231–234 \| doi = 10.1007/BF02630880 \| s2cid = 84893770 }}
Peanut oil	19.6%	{{cite web \|url=https://fdc.nal.usda.gov/fdc-app.html#/food-details/1750348/nutrients \|title=Oil, peanut \|date=April 2021 \|website=FoodData Central \|publisher=USDA \|access-date=6 April 2022 \|archive-date=3 April 2019 \|archive-url=https://web.archive.org/web/20190403171801/https://fdc.nal.usda.gov/fdc-app.html#/food-details/1750348/nutrients \|url-status=dead }}
Egg yolk	16%
Linseed oil (flax), cold pressed	14.2%	{{cite web \|url=https://fdc.nal.usda.gov/fdc-app.html#/food-details/167702/nutrients \|title=Oil, flaxseed, cold pressed \|date=April 2019 \|website=FoodData Central \|publisher=USDA \|access-date=6 April 2022 \|archive-date=3 April 2019 \|archive-url=https://web.archive.org/web/20190403171801/https://fdc.nal.usda.gov/fdc-app.html#/food-details/167702/nutrients \|url-status=dead }}
Lard	10%
Palm oil	10%
Olive oil	8.4%	{{cite web \|url=https://fdc.nal.usda.gov/fdc-app.html#/food-details/748608/nutrients \|title=Oil, olive, extra virgin \|date=December 2019 \|website=FoodData Central \|publisher=USDA \|access-date=6 April 2022 \|archive-date=3 April 2019 \|archive-url=https://web.archive.org/web/20190403171801/https://fdc.nal.usda.gov/fdc-app.html#/food-details/748608/nutrients \|url-status=dead }}
Tallow \|3% \|
Cocoa butter	3%
Macadamia oil	2%
Butter	2%
Coconut oil	2%
\| \| colspan=2\|^†average val, except the items where a range is given

=Other occurrences=

Cockroaches release oleic and linoleic acid upon death, which discourages other roaches from entering the area. This is similar to the mechanism found in ants and bees, which release oleic acid upon death.{{cite news|url=http://news.bbc.co.uk/earth/hi/earth_news/newsid_8232000/8232607.stm|title=Earth News: Ancient 'smell of death' revealed|publisher=BBC|date=2009-09-09}}

Related compounds

While polyunsaturated fatty acids are unusual in plant cuticles, a diunsaturated dicarboxylic acid has been reported as a component of the surface waxes or polyesters of some plant species. Thus, {{Chem name|octadeca-c6,c9-diene-1,18-dioate}}, a derivative of linoleic acid, is present in Arabidopsis and Brassica napus cuticle.{{cite journal |last1=Bonaventure |first1=Gustavo |last2=Ohlrogge |first2=John |last3=Pollard |first3=Mike |title=Analysis of the aliphatic monomer composition of polyesters associated with Arabidopsis epidermis: occurrence of octadeca-cis-6, cis-9-diene-1,18-dioate as the major component |journal=The Plant Journal |date=2004 |volume=40 |issue=6 |pages=920–930 |doi=10.1111/j.1365-313X.2004.02258.x |pmid=15584957 |doi-access=free}}

Health effects

Consumption of linoleic acid has been associated with lowering the risk of cardiovascular disease, diabetes and premature death.{{cite journal

|last1=Li |first1=Jun

|last2=Guasch-Ferré |first2=Marta

|last3=Li |first3=Yanping

|last4=Hu |first4=Frank B.

|year=2020|title=Dietary intake and biomarkers of linoleic acid and mortality: systematic review and meta-analysis of prospective cohort studies|journal=The American Journal of Clinical Nutrition|volume=112|issue=1|pages=150–167|pmid= 32020162|doi=10.1093/ajcn/nqz349|pmc=7326588}}{{cite journal

|last1=Marangoni |first1=Franca

|last2=Agostoni |first2=Carlo

|last3=Borghi |first3=Claudio

|last4=Catapano |first4=Alberico L.

|last5=Cena |first5=Hellas

|last6=Ghiselli |first6=Andrea

|last7=La Vecchia |first7=Carlo

|last8=Lercker |first8=Giovanni

|last9=Manzato |first9=Enzo

|last10=Pirillo |first10=Angela

|last11=Riccardi |first11=Gabriele

|last12=Risé |first12=Patrizia

|last13=Visioli |first13=Francesco

|last14=Poli |first14=Andrea

}}{{cite journal

|last1=Mousavi |first1=Seyed Mohammad

|last2=Jalilpiran |first2=Yahya

|last3=Karimi |first3=Elmira

|last4=Aune |first4=Dagfinn

|last5=Larijani |first5=Bagher

|last6=Mozaffarian |first6=Dariush

|last7=Willett |first7=Walter C.

|last8=Esmaillzadeh |first8=Ahmad

|doi-access=free}} There is high-quality evidence that increased intake of linoleic acid decreases total blood cholesterol and low-density lipoprotein.[https://www.foodstandards.gov.au/sites/default/files/consumer/labelling/nutrition/Documents/Systematic%20review%20fatty%20acids%20cholesterol.pdf "Systematic review of the evidence for relationships between saturated, cis monounsaturated, cis polyunsaturated fatty acids and selected individual fatty acids, and blood cholesterol concentration"]. foodstandards.gov.au. Retrieved 10 January 2023. Higher in vivo circulating and tissue levels of linoleic acid are associated with a lower risk of major cardiovascular events.{{cite journal|author=Marklund M, Wu JHY, Imamura F, Del Gobbo LC, Fretts A, de Goede J, Shi P, Tintle N, Wennberg M, Aslibekyan S, Chen TA, de Oliveira Otto MC, Hirakawa Y, Eriksen HH, Kröger J, Laguzzi F, Lankinen M, Murphy RA, Prem K, Samieri C, Virtanen J, Wood AC, Wong K, Yang WS, Zhou X, Baylin A, Boer JMA, Brouwer IA, Campos H, Chaves PHM, Chien KL, de Faire U, Djoussé L, Eiriksdottir G, El-Abbadi N, Forouhi NG, Michael Gaziano J, Geleijnse JM, Gigante B, Giles G, Guallar E, Gudnason V, Harris T, Harris WS, Helmer C, Hellenius ML, Hodge A, Hu FB, Jacques PF, Jansson JH, Kalsbeek A, Khaw KT, Koh WP, Laakso M, Leander K, Lin HJ, Lind L, Luben R, Luo J, McKnight B, Mursu J, Ninomiya T, Overvad K, Psaty BM, Rimm E, Schulze MB, Siscovick D, Skjelbo Nielsen M, Smith AV, Steffen BT, Steffen L, Sun Q, Sundström J, Tsai MY, Tunstall-Pedoe H, Uusitupa MIJ, van Dam RM, Veenstra J, Monique Verschuren WM, Wareham N, Willett W, Woodward M, Yuan JM, Micha R, Lemaitre RN, Mozaffarian D, Risérus U|year=2019|title=Biomarkers of Dietary Omega-6 Fatty Acids and Incident Cardiovascular Disease and Mortality: An Individual-Level Pooled Analysis of 30 Cohort Studies|journal=Circulation|url=https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.118.038908|volume=139|issue=21|pages=2422-2436|doi=10.1161/CIRCULATIONAHA.118.038908|pmid=30971107|hdl=1959.4/unsworks_67124|hdl-access=free}} Clinical trials have shown that increased linoleic acid intake does not increase markers of inflammation or oxidative stress.{{cite journal|author=Johnson GH, Fritsche K.|year=2012|title=Effect of dietary linoleic acid on markers of inflammation in healthy persons: a systematic review of randomized controlled trials|journal=Journal of the Academy of Nutrition and Dietetics|volume=112|issue=7|pages=1029-1041|doi=10.1016/j.jand.2012.03.029|pmid=22889633}}{{cite journal|author=Petersen KS, Maki KC, Calder PC, Belury MA, Messina M, Kirkpatrick CF, Harris WS.|year=2024|title=Perspective on the health effects of unsaturated fatty acids and commonly consumed plant oils high in unsaturated fat|journal=British Journal of Nutrition|volume=30|issue=|pages=1-12|doi=10.1017/S0007114524002459|pmid=39475012|doi-access=free|pmc=11600290}}

The American Heart Association advises people to replace saturated fat with linoleic acid to reduce CVD risk.{{Cite journal |vauthors=Sacks FM, Lichtenstein AH, Wu JH, Appel LJ, Creager MA, Kris-Etherton PM, Miller M, Rimm EB, Rudel LL, Robinson JG, Stone NJ, Van Horn LV |date=July 2017 |title=Dietary Fats and Cardiovascular Disease: A Presidential Advisory From the American Heart Association |journal=Circulation |volume=136 |issue=3 |pages=e1–e23 |doi=10.1161/CIR.0000000000000510 |pmid=28620111 |doi-access=free |s2cid=367602}}

References

F. Sacc (1844). [https://zenodo.org/record/1612638/files/article.pdf "Ueber das Leinöl, seine physicalischen und chemischen Eigenschaften und seine Oxydationsproducte"]. Liebigs Annalen, volume 51, issue 2, pages 213–230. {{doi|10.1002/jlac.18440510207}}.

F. Sacc (1845). [https://www.biodiversitylibrary.org/item/47526#page/191/mode/1up "Expériences sur les propriétés physiques et chimiques de l'huile de Lin"]. Neue Denkschriften der Allg. Schweizerischen Gesellschaft für die Gesammten Naturwissenschaften, volume 7, pages 191–208 in pdf.

{{cite journal |title=On the Nature and Rôle of the Fatty Acids Essential in Nutrition |vauthors=Burr GO, Burr MM |date=April 1930 |journal=J. Biol. Chem. |volume=86 |issue=2 |pages=587–621 |doi=10.1016/S0021-9258(20)78929-5 |doi-access=free}}

{{cite journal |title=The synthesis of long-chain aliphatic acids from acetylenic compounds. Part III. The synthesis of linoleic acid |last1=Raphael |first1=R.A. |author-link1=Ralph Raphael |last2=Sondheimer |first2=Franz |author-link2=Franz Sondheimer |year=1950 |journal=Journal of the Chemical Society (Resumed) |pages=article 432, pp 2100–2103 |doi=10.1039/jr9500002100}}

External links

[http://gmd.mpimp-golm.mpg.de/Spectrums/36c6cc53-c36d-4485-8c63-615d001552d3.aspx Linoleic acid MS Spectrum]
[https://web.archive.org/web/20110827030232/http://lipidlibrary.aocs.org/Lipids/fa_poly/index.htm Fatty Acids: Methylene-Interrupted Double Bonds], AOCS Lipid Library

Category:5α-Reductase inhibitors

Category:Alkenoic acids

Category:Aromatase inhibitors

Category:Essential fatty acids

Category:Essential nutrients

Category:Fatty acids

Category:Wood extracts