Vaccenic acid
Skeletal formula
Ball-and-stick model
Preferred IUPAC name
(11E)-Octadec-11-enoic acid
3D model (JSmol)
ECHA InfoCard 100.010.691 Edit this at Wikidata
  • InChI=1S/C18H34O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18(19)20/h7-8H,2-6,9-17H2,1H3,(H,19,20)/b8-7+ checkY
  • InChI=1/C18H34O2/c1-2-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18(19)20/h7-8H,2-6,9-17H2,1H3,(H,19,20)/b8-7+
Molar mass 282.461 g/mol
Melting point 44 °C (111 °F)
Boiling point 172 °C (342 °F)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Vaccenic acid is a naturally occurring trans fatty acid and an omega-7 fatty acid. It is the predominant kind of trans-fatty acid found in human milk, in the fat of ruminants, and in dairy products such as milk, butter, and yogurt.[1][2] Trans fat in human milk may depend on trans fat content in food.[3][4]

Its IUPAC name is (11E)-11-octadecenoic acid, and its lipid shorthand name is 18:1 trans-11. The name was derived from the Latin vacca (cow).[4]

Vaccenic acid was discovered in 1928 in animal fats and butter. Mammals convert it into rumenic acid, a conjugated linoleic acid,[5][6] where it shows anticarcinogenic properties.[7]

Its stereoisomer, cis-vaccenic acid, is found in Sea Buckthorn (Hippophae rhamnoides) oil.[8] Its IUPAC name is (11Z)-11-octadecenoic acid, and its lipid shorthand name is 18:1 cis-11.

Cows milk had highest trans-vaccenic acid content in the first few days of the cows being milked,[9] indicating that it is stockpiled similarly to omega-3 fatty acids.


Two Canadian studies have shown that vaccenic acid could hold benefits over trans fats derived from vegetable shortenings, or a mixture of pork lard and soy fat, by lowering total LDL and triglyceride levels.[10][11][12][13][14] A study by the US Department of Agriculture showed that vaccenic acid raises both HDL and LDL cholesterol, whereas industrial trans fats only raise LDL with no beneficial effect on HDL.[15]

Obese rats fed a diet enriched with vaccenic acid for 16 weeks had a reduction in total cholesterol, LDL cholesterol and lower triglyceride levels,[16] with an effect comparable to CLA. This effect was not seen in lean rats.[17]

Vaccenic acid accumulates in the orbitofrontal cortex to a higher extent in patients with bipolar disorder and schizophrenia.[18][19]

Oxidation of omega-7 unsaturated fatty acids on the skin surface, such as palmitoleic acid and vaccenic acid, may be the cause of the phenomenon commonly known as old person smell.[20]

Alkaline phosphatase was inhibited 25% by vaccenic acid in osteoblasts.[21]

A 2023 University of Chicago study found that trans-vaccenic acid enhances anti-tumor immunity by activating CD8+ T cells. This effect is accomplished by deactivating a GPR43 receptor, which activates the CREB pathway instead. The effect was produced with a diet containing 1% w/w TVA.[22]


  1. ^ Bowerman, Susan (May 19, 2008). "Now there are good trans fats?". Los Angeles Times.
  2. ^ Precht D, Molkentin J (August 1999). "C18:1, C18:2 and C18:3 trans and cis fatty acid isomers including conjugated cis delta 9, trans delta 11 linoleic acid (CLA) as well as total fat composition of German human milk lipids". Nahrung. 43 (4): 233–44. doi:10.1002/(SICI)1521-3803(19990801)43:4<233::AID-FOOD233>3.0.CO;2-B. PMID 10481820.
  3. ^ Friesen R, Innis SM (October 2006). "Trans fatty acids in human milk in Canada declined with the introduction of trans fat food labeling". J. Nutr. 136 (10): 2558–61. doi:10.1093/jn/136.10.2558. PMID 16988126.
  4. ^ a b Destaillats F, Buyukpamukcu E, Golay PA, Dionisi F, Giuffrida F (2005). "Letter to the Editor: Vaccenic and Rumenic Acids, A Distinct Feature of Ruminant Fats". Journal of Dairy Science. 88 (449): 449. doi:10.3168/jds.S0022-0302(05)72705-3. PMID 15653508.
  5. ^ Bauman, Dale. "cis-9, trans-11 CLA - A Potent Anticarcinogen Found in Milk Fat". Archived from the original on 2006-09-07. Retrieved 2007-01-15.
  6. ^ Banni S, Angioni E, Murru E, Carta G, Melis M, Bauman D, Dong Y, Ip C (2001). "Vaccenic acid feeding increases tissue levels of conjugated linoleic acid and suppresses development of premalignant lesions in rat mammary gland". Nutr Cancer. 41 (1–2): 91–7. doi:10.1080/01635581.2001.9680617. PMID 12094634. S2CID 2920114.
  7. ^ Lock AL, Corl BA, Barbano DM, Bauman DE, Ip C (October 1, 2004). "The anticarcinogenic effect of trans-11 18:1 is dependent on its conversion to cis-9, trans-11 CLA by delta9-desaturase in rats". J Nutr. 134 (10): 2698–704. doi:10.1093/jn/134.10.2698. PMID 15465769. Retrieved 2007-01-15.
  8. ^ Federal Research Centre for Nutrition and Food - Institute for Lipid Research. "Seed Oil Fatty Acids Database".
  9. ^ Bainbridge, Melissa L.; Cersosimo, Laura M.; Wright, André-Denis G.; Kraft, Jana (2016-03-01). Brockmann, Gudrun A. (ed.). "Content and Composition of Branched-Chain Fatty Acids in Bovine Milk Are Affected by Lactation Stage and Breed of Dairy Cow". PLOS ONE. 11 (3): e0150386. Bibcode:2016PLoSO..1150386B. doi:10.1371/journal.pone.0150386. ISSN 1932-6203. PMC 4773160. PMID 26930646.
  10. ^ Trans Fats From Ruminant Animals May Be Beneficial – Health News. redOrbit (8 September 2011). Retrieved 22 January 2013.
  11. ^ Bassett, C. M. C.; Edel, A. L.; Patenaude, A. F.; McCullough, R. S.; Blackwood, D. P.; Chouinard, P. Y.; Paquin, P.; Lamarche, B.; Pierce, G. N. (Jan 2010). "Dietary Vaccenic Acid Has Antiatherogenic Effects in LDLr-/- Mice". The Journal of Nutrition. 140 (1): 18–24. doi:10.3945/jn.109.105163. PMID 19923390.
  12. ^ Wang, Flora & Proctor, Spencer (2 April 2008). "Natural trans fats have health benefits, University of Alberta study shows" (Press release). University of Alberta.
  13. ^ Wang Y, Jacome-Sosa MM, Vine DF, Proctor SD (20 May 2010). "Beneficial effects of vaccenic acid on postprandial lipid metabolism and dyslipidemia: Impact of natural trans-fats to improve CVD risk". Lipid Technology. 22 (5): 103–106. doi:10.1002/lite.201000016.
  14. ^ Bassett C, Edel AL, Patenaude AF, McCullough RS, Blackwood DP, Chouinard PY, Paquin P, Lamarche B, Pierce GN (2010). "Dietary Vaccenic Acid Has Antiatherogenic Effects in LDLr−/− Mice". The Journal of Nutrition. 140 (1): 18–24. doi:10.3945/jn.109.105163. PMID 19923390.
  15. ^ David J. Baer, PhD. US Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Laboratory. New Findings on Dairy Trans Fat and Heart Disease Risk, IDF World Dairy Summit 2010, 8–11 November 2010. Auckland, New Zealand
  16. ^ AFNS. Alberta natural trans fat research earns global recognition Archived 2008-06-15 at the Wayback Machine. April 2, 2008.
  17. ^ Wang, Ye; Jacome-Sosa, M. Miriam; Vine, Donna F.; Proctor, Spencer D. (May 2010). "Beneficial effects of vaccenic acid on postprandial lipid metabolism and dyslipidemia: Impact of natural trans -fats to improve CVD risk". Lipid Technology. 22 (5): 103–106. doi:10.1002/lite.201000016. ISSN 0956-666X.
  18. ^ McNamara, RK; Jandacek, R; Rider, T; Tso, P; Hahn, CG; Richtand, NM; Stanford, KE (2007). "Abnormalities in the fatty acid composition of the postmortem orbitofrontal cortex of schizophrenic patients: gender differences and partial normalization with antipsychotic medications". Schizophr Res. 91 (1–3): 37–50. doi:10.1016/j.schres.2006.11.027. PMC 1853256. PMID 17236749.
  19. ^ McNamara, RK; Jandacek, R; Rider, T; Tso, P; Stanford, KE; Hahn, CG; Richtand, NM (2008). "Deficits in docosahexaenoic acid and associated elevations in the metabolism of arachidonic acid and saturated fatty acids in the postmortem orbitofrontal cortex of patients with bipolar disorder". Psychiatry Research. 160 (3): 285–299. doi:10.1016/j.psychres.2007.08.021. PMC 2620106. PMID 18715653.
  20. ^ Haze S, Gozu Y, Nakamura S, Kohno Y, Sawano K, Ohta H, Yamazaki K (April 2001). "2-Nonenal newly found in human body odor tends to increase with aging". J. Invest. Dermatol. 116 (4): 520–4. doi:10.1046/j.0022-202x.2001.01287.x. PMID 11286617.
  21. ^ Hamazaki K, Suzuki N, Kitamura K, Hattori A, Nagasawa T, Itomura M, Hamazaki T (June 2016). "Is vaccenic acid (18:1t n-7) associated with an increased incidence of hip fracture? An explanation for the calcium paradox". Prostaglandins Leukot. Essent. Fatty Acids. 109: 8–12. doi:10.1016/j.plefa.2016.04.001. PMID 27269708.
  22. ^ Fan H, Xia S, Xiang J, et al. (22 November 2023). "Trans-vaccenic acid reprograms CD8+ T cells and anti-tumour immunity". Nature. 623 (7989): 1034–1043. doi:10.1038/s41586-023-06749-3. PMC 10686835. PMID 37993715.