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Vaccenic acid
Vaccenic acid
Vaccenic acid
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Vaccenic acid
Skeletal formula
Skeletal formula
Ball-and-stick model
Ball-and-stick model
Names
Preferred IUPAC name
(11E)-Octadec-11-enoic acid
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.010.691 Edit this at Wikidata
UNII
  • 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
    Key: UWHZIFQPPBDJPM-BQYQJAHWSA-N 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+
    Key: UWHZIFQPPBDJPM-BQYQJAHWBK
  • CCCCCC/C=C/CCCCCCCCCC(O)=O
Properties
C18H34O2
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).
checkY verify (what is checkY☒N ?)

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] Vaccenic acid was discovered in 1928 in animal fats and butter. Mammals convert it into rumenic acid, a conjugated linoleic acid,[5]

Cow milk had highest trans-vaccenic acid content in the first few days of milking.[6]

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] Its stereoisomer, cis-vaccenic acid, is found in sea buckthorn (Hippophae rhamnoides) oil.[7] Its IUPAC name is (11Z)-11-octadecenoic acid, and its lipid shorthand name is 18:1 cis-11.

References

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Vaccenic acid

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from Grokipedia
Vaccenic acid is a naturally occurring trans monounsaturated with the molecular formula C₁₈H₃₄O₂ and the IUPAC name (11E)-octadec-11-enoic acid, featuring an 18-carbon chain with a trans between carbons 11 and 12. It is the predominant trans in fats, products such as , , and , and human , where its content can vary based on dietary factors in s. Unlike industrially produced trans fats, vaccenic acid is biosynthesized in the of animals through biohydrogenation of dietary unsaturated fats. Chemically, vaccenic acid has a molar mass of 282.468 g/mol, a melting point of 44 °C, and low water solubility of approximately 0.00012 g/L, classifying it as a solid at room temperature with properties typical of long-chain fatty acids. It serves as a key dietary precursor to conjugated linoleic acid (CLA), particularly the beneficial c9,t11-CLA isomer (rumenic acid), via delta-9 desaturation in tissues like the mammary gland or human adipocytes. This endogenous conversion pathway underscores its role in lipid metabolism, with vaccenic acid comprising up to 25% of the concentration of oleic acid (18:1n9) in certain phospholipids. In terms of health implications, natural vaccenic acid from sources has been linked to , anti-carcinogenic, and insulin-sensitizing effects, potentially reducing risks of , hepatic , and certain cancers through CLA production and direct cellular mechanisms. For instance, it suppresses intestinal by elevating levels and reprograms immune cells to enhance anti-tumor activity in models of cancer. Dietary enrichment with vaccenic acid, such as in , has also shown benefits in attenuating obesity-related glucose intolerance and improving profiles in high-fat diet studies. However, its effects can differ based on source, with ruminant-derived forms generally conferring positive outcomes compared to those from processed vegetable oils.

Chemical Properties

Structure and Nomenclature

Vaccenic acid is a monounsaturated with the molecular formula C18H34O2C_{18}H_{34}O_2, featuring a straight chain of 18 carbon atoms and a single carbon-carbon . Its primary form is the trans isomer, known as trans-11-octadecenoic acid or (11E)-octadec-11-enoic acid, where the double bond is positioned between carbons 11 and 12 in the trans configuration. This trans results in a more linear and extended chain conformation compared to cis counterparts, influencing its packing in structures. The systematic IUPAC name is (11E)-octadec-11-enoic acid, while its common shorthand notation is 18:1t11 or t11-18:1. The name "vaccenic acid" originates from the Latin word vacca (cow), reflecting its initial discovery in in animal fats and by S.H. Bertram. It is often abbreviated as VA or t-VA in . A related is cis-vaccenic acid, or cis-11-octadecenoic acid ((11Z)-octadec-11-enoic acid), which differs in the cis configuration of the at the same position. Both vaccenic acid and its cis are classified as omega-7 fatty acids, as the is located seven carbons from the methyl (omega) end of the chain.

Physical and Chemical Characteristics

Vaccenic acid, specifically the trans-11-octadecenoic acid , is a white to off-white solid at due to its of 44°C, which is notably higher than that of cis-unsaturated fatty acids owing to the greater molecular rigidity imparted by the trans configuration. This elevated distinguishes it from more fluid cis counterparts like , contributing to its semi-solid or waxy appearance in pure form. It exhibits low in , being practically insoluble as a hydrophobic , but dissolves readily in organic solvents such as , , and DMSO. The specific gravity is approximately 0.856 g/cm³ at ambient conditions, reflecting its non-polar nature. Its boiling point is estimated at 398°C under standard pressure, though it decomposes or requires reduced pressure for practical around 350°C to avoid thermal breakdown. Chemically, vaccenic acid participates in standard reactions of monounsaturated fatty acids, such as hydrogenation to form stearic acid, esterification to yield methyl or ethyl esters, and oxidation via auto-oxidation or enzymatic pathways. The trans double bond enhances its stability relative to cis isomers, rendering it less susceptible to oxidative degradation and isomerization under heat or air exposure; for instance, trans-unsaturated fatty acids like vaccenic acid demonstrate lower oxidizability than cis-oleic acid in lipid environments. This configuration also imparts resistance to free radical attack, making it more stable during processing or storage compared to cis counterparts.

Natural Occurrence

In Ruminant Products

Vaccenic acid, a trans-18:1 monounsaturated , is prominently found in fats derived from animals, including , , and from cows, sheep, and goats. These products serve as the primary dietary sources of vaccenic acid for humans, as it is produced endogenously in the through the biohydrogenation of unsaturated plant-derived fatty acids such as (18:2 n-6) and α-linolenic acid (18:3 n-3). In fats, vaccenic acid typically constitutes 2-6% of total s, with detection and quantification commonly achieved through of fatty acid methyl esters, often coupled with flame ionization detection for precise isomer separation. For instance, in cow , concentrations range from 1-3% of total s, averaging around 2.7%, while in , levels are similarly 2-5%, and butter—derived directly from —exhibits comparable profiles. Sheep and goat fats also contain vaccenic acid at 1-4%, though sheep milk often shows slightly higher levels under identical feeding conditions. Concentrations of vaccenic acid in ruminant products vary significantly based on animal diet, with grass-fed or pasture-based systems yielding higher levels—up to 2-3 times more than in grain-fed animals—due to increased biohydrogenation of . Seasonal influences further modulate content, as spring pastures rich in polyunsaturated elevate vaccenic acid in by enhancing microbial activity in the . Dietary supplementation, such as with linseed or organic feeds, can also boost levels, as observed in improved systems where reaches 1.8-2.8%.

In Human Milk and Other Sources

Vaccenic acid serves as the predominant trans fatty acid in human milk, typically comprising 0.2–0.7% of total fatty acids, with levels influenced by maternal dietary habits. These concentrations reflect direct transfer from the mother's circulation, particularly elevated by intake of products, which are the primary -derived source of vaccenic acid in human diets. Global variations exist, with higher proportions observed in Western populations (e.g., 0.24–0.73% in the United States) compared to those in or , where traditional diets limit ruminant fat consumption. Beyond human milk, vaccenic acid occurs in trace amounts in non-ruminant sources. In plant-derived oils, it is naturally low but can appear at minimal levels (often <0.1% of total fatty acids) in partially hydrogenated oils due to industrial processing. Microbial sources include certain capable of producing vaccenic acid through biohydrogenation processes, similar to those in ruminant guts, and it has been identified in fermented foods or bacterial cultures used in . Average dietary intake of vaccenic acid in humans from mixed diets ranges from 0.1–0.5 g per day, primarily sourced from and , with higher estimates (up to 1.3–1.8 g per day) in populations with elevated consumption of these foods.

Biosynthesis and Metabolism

Production in Ruminants

Vaccenic acid, or trans-11-octadecenoic acid, is primarily produced in the of animals through the process of ruminal biohydrogenation, where anaerobic convert dietary polyunsaturated fatty acids into more saturated forms. This microbial transformation occurs in the of ruminants such as and sheep, enabling them to utilize plant-based unsaturated fats from . The key bacteria involved in this pathway include Butyrivibrio fibrisolvens, a prominent microbe that catalyzes the biohydrogenation of (18:2 n-6), a common dietary polyunsaturated fatty acid derived from plant lipids. The process begins with the isomerization of the cis-12 double bond in to a trans-11 configuration, forming the conjugated intermediate cis-9, trans-11-octadecadienoic acid (rumenic acid, a form of ). This is followed by incomplete of the cis-9 double bond, yielding trans-11-octadecenoic acid (vaccenic acid) as the primary intermediate. The simplified biochemical pathway can be represented as: Linoleic acid (18:2 *n*-6)→cis-9, trans-11 CLA→Vaccenic acid (trans-11 18:1)\text{Linoleic acid (18:2 *n*-6)} \rightarrow \text{cis-9, trans-11 CLA} \rightarrow \text{Vaccenic acid (trans-11 18:1)} Further reduction to stearic acid (18:0) often remains incomplete, allowing vaccenic acid to accumulate. Conversion yields from linoleic acid to vaccenic acid can reach up to 89% under optimal conditions mediated by B. fibrisolvens, though typical rumen extents vary between 70% and 90% depending on environmental factors. Diet composition significantly influences production, with high-forage diets promoting the trans-11 pathway and higher vaccenic acid output, whereas high-concentrate (starch-rich) diets shift microbial activity toward alternative trans-10 pathways, reducing vaccenic acid formation. Rumen pH also plays a critical role; lower pH levels (around 5.5–6.0), often associated with high-concentrate feeding, inhibit B. fibrisolvens activity and decrease biohydrogenation efficiency. Additionally, the rumen microbial population dynamics, including the abundance of Butyrivibrio species, are modulated by dietary shifts, further affecting vaccenic acid synthesis rates.

Conversion in Humans

Vaccenic acid, primarily obtained from dietary sources such as products, is absorbed in the human following of dietary triglycerides into free fatty acids and monoglycerides. These components are taken up by enterocytes, re-esterified into triglycerides, and packaged into chylomicrons for lymphatic transport into the bloodstream. Once in circulation, chylomicrons deliver vaccenic acid to peripheral tissues, including the liver and , where it is metabolized. In human tissues, vaccenic acid (trans-11-octadecenoic acid, t11-18:1) undergoes delta-9 desaturation primarily through the action of the stearoyl-CoA desaturase (SCD), converting it to rumenic acid (cis-9,trans-11-octadecadienoic acid, c9,t11-18:2), a key of (CLA). This bioconversion occurs notably in the liver, , and . The SCD , located in the endoplasmic reticulum, introduces a cis double bond at the delta-9 position of the fatty acyl-CoA substrate, utilizing molecular oxygen and electrons from NADH via a b5 reductase intermediate. The simplified reaction is as follows: t11-18:1 (acyl-CoA)+O2+2H++2e− (from NADH)→c9,t11-18:2 (acyl-CoA)+2H2O\text{t11-18:1 (acyl-CoA)} + \text{O}_2 + 2\text{H}^+ + 2\text{e}^- \ (from\ NADH) \rightarrow \text{c9,t11-18:2 (acyl-CoA)} + 2\text{H}_2\text{O} The liver is considered the principal site of this desaturation due to its high fatty acid synthesis capacity, though significant activity also takes place in adipose and mammary tissues. Conversion efficiency of ingested vaccenic acid to CLA in humans ranges from 5% to 20%, with interindividual variation influenced by factors such as diet and enzyme expression; studies report averages of 19% in plasma and 24% in serum based on controlled interventions with 1.5–4.5 g/day vaccenic acid intake. This process contributes substantially to the endogenous CLA pool, accounting for approximately one-quarter of total CLA in humans. Efficiency appears higher in women, particularly during lactation, where tracer studies demonstrate up to 7.6% incorporation of labeled vaccenic acid into milk fat and subsequent conversion to CLA at levels exceeding 0.4%, reflecting upregulated SCD activity in mammary tissue.

Health Implications

Potential Benefits

Vaccenic acid, particularly its trans-11 , has shown potential anti-cancer effects in preclinical studies. A 2023 study demonstrated that dietary trans-vaccenic acid enhances + T cell function and anti-tumor immunity in mouse models of and colon cancer by promoting effector T cell differentiation and reprogramming T cell metabolism through inhibition of the GPR43 receptor. This suggests a role in boosting adaptive immune responses against tumors, positioning trans-vaccenic acid as a possible dietary adjunct to . As a direct precursor to cis-9,trans-11-conjugated (CLA) via delta-9 desaturase activity in tissues, vaccenic acid contributes to metabolic benefits associated with CLA. Human clinical trials of CLA supplementation (typically 3-6 g/day, approximating 1-3 g equivalent from vaccenic acid conversion) have reported reductions in body fat mass by 0.1-1 kg over 12 weeks and mixed effects on insulin sensitivity, as measured by HOMA-IR indices in individuals, including some reports of improvements. Additionally, these trials indicate lowered markers of , such as , in some clinical studies. In terms of cardiovascular health, natural vaccenic acid may favorably influence profiles. Animal studies have shown that diets enriched with trans-11-vaccenic acid increase (HDL) cholesterol levels and reduce postprandial triglycerides in hyperlipidemic models. Unlike industrially produced trans fats, which elevate cardiovascular risk, epidemiological and clinical data on natural vaccenic acid from sources reveal no association with heart disease or adverse changes in humans. Beyond these areas, vaccenic acid supports broader immune modulation, as evidenced by its enhancement of T cell responses in anti-tumor contexts. The cis-11 isomer of vaccenic acid exhibits potential therapeutic value in by inducing erythroid differentiation and up-regulating γ-globin synthesis in human cell lines and transgenic mouse models, offering a novel approach to induction as an alternative to hydroxyurea. Additionally, a 2024 found associations between plasma cis-vaccenic acid levels and improved insulin sensitivity in men with .

Safety and Risks

Vaccenic acid is classified as a natural trans fatty acid primarily derived from ruminant animal products, distinguishing it from industrial trans fats such as elaidic acid, which originate from partially hydrogenated oils. The U.S. (FDA) has determined that partially hydrogenated oils are no longer and banned their use in food by January 2021, effectively targeting industrial s while leaving natural sources like vaccenic acid unaffected. Similarly, the (WHO) focuses its REPLACE initiative on eliminating industrially produced trans fats, recommending that total trans fat intake be limited to less than 1% of total energy intake (approximately 2 g per day for a 2,000 kcal diet), with ruminant-derived trans fats such as vaccenic acid permitted within this overall guideline rather than facing specific restrictions. At typical dietary intake levels of 0.5–1 g per day from sources like and meat, vaccenic acid shows no strong evidence of adverse cardiovascular effects in humans, in contrast to artificial trans fats that consistently elevate () cholesterol. Human intervention studies at higher doses show mixed effects, but at typical dietary levels (0.5–1 g per day), vaccenic acid shows no strong evidence of increasing cholesterol, unlike , which raises by 5–10% in comparable amounts. Although some trials report minor elevations in total (2–6%) similar to industrial trans fats, these effects are less pronounced and not associated with increased or at natural intake levels. Potential concerns with vaccenic acid arise primarily from high intake scenarios, where it could contribute to the overall trans fat burden and potentially exacerbate risks if combined with industrial sources, though such levels exceed typical diets. Long-term human data remain limited, with most evidence from short-term trials (up to 8 weeks) or observational studies showing neutral outcomes, and the cis isomer of vaccenic acid (cis-11-octadecenoic acid) has been examined separately for its distinct properties without direct comparison to the trans form in safety contexts. As a naturally occurring nutrient in food matrices like dairy (1–5% of total fat), vaccenic acid has no reported toxicity at typical intake levels.

References

  1. https://hmdb.ca/metabolites/HMDB0003231
  2. https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/vaccenic-acid
  3. https://ecmdb.ca/compounds/ECMDB21443
  4. https://pubmed.ncbi.nlm.nih.gov/19935865/
  5. https://pmc.ncbi.nlm.nih.gov/articles/PMC4808772/
  6. https://pmc.ncbi.nlm.nih.gov/articles/PMC10802129/
  7. https://pmc.ncbi.nlm.nih.gov/articles/PMC8707829/
  8. https://www.sciencedirect.com/topics/medicine-and-dentistry/vaccenic-acid
  9. https://www.journalofdairyscience.org/article/S0022-0302(05)72705-3/fulltext
  10. https://www.chemicalbook.com/ChemicalProductProperty_US_CB4750132.aspx
  11. https://www.medchemexpress.com/trans-Vaccenic_acid.html
  12. https://pubmed.ncbi.nlm.nih.gov/14516205/
  13. https://www.ahajournals.org/doi/10.1161/circulationaha.106.181947
  14. https://pmc.ncbi.nlm.nih.gov/articles/PMC11275335/
  15. https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/vaccenic-acid
  16. https://pmc.ncbi.nlm.nih.gov/articles/PMC2596709/
  17. https://www.sciencedirect.com/science/article/abs/pii/S096399691000219X
  18. https://www.researchgate.net/publication/243987829_Comparative_study_between_sheep_and_goats_rumenic_acid_and_vaccenic_acid_in_milk_fat_under_the_same_dietary_treatments
  19. https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2022.851494/full
  20. https://pmc.ncbi.nlm.nih.gov/articles/PMC10954868/
  21. https://ajcn.nutrition.org/article/S0002-9165%2823%2927206-8/fulltext
  22. https://www.sciencedirect.com/topics/nursing-and-health-professions/vaccenic-acid
  23. https://pmc.ncbi.nlm.nih.gov/articles/PMC7339423/
  24. https://www.sciencedirect.com/science/article/pii/S0022030224010701
  25. https://www.sciencedirect.com/science/article/pii/S175173111000042X
  26. https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2023.1322869/full
  27. https://pubmed.ncbi.nlm.nih.gov/9392416/
  28. https://www.sciencedirect.com/science/article/pii/S0002916523059269
  29. https://link.springer.com/article/10.1007/s11745-003-1107-8
  30. https://pubmed.ncbi.nlm.nih.gov/12197992/
  31. https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/trans1118-1-is-effectively-9desaturated-compared-with-trans1218-1-in-humans/B163C0C98A1DFD2E77F362640E2DC6AF
  32. https://pubmed.ncbi.nlm.nih.gov/16920844/
  33. https://www.nature.com/articles/s41586-023-06749-3
  34. https://www.mdpi.com/2072-6643/11/2/370
  35. https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/s12986-023-00758-9
  36. https://www.mdpi.com/2076-2607/9/12/2517
  37. https://cdnsciencepub.com/doi/10.1139/H09-079
  38. https://www.sciencedirect.com/science/article/abs/pii/S0014299916300668
  39. https://www.nature.com/articles/s41387-024-00332-z
  40. https://www.fda.gov/food/food-additives-petitions/trans-fat
  41. https://www.who.int/news-room/fact-sheets/detail/trans-fat
  42. https://pubmed.ncbi.nlm.nih.gov/26561632/
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