Omega-6 fatty acid

Omega-6 fatty acids (also referred to as ω-6 fatty acids or n-6 fatty acids) are a family of polyunsaturated fatty acids that have in common a final carbon-carbon double bond in the n-6 position, that is, the sixth bond, counting from the methyl end.[1]

The evening primrose flower (O. biennis) produces an oil containing a high content of γ-linolenic acid, a type of omega-6 fatty acid.

Health effects

One review found that an increased intake of omega‐6 fatty acids has been shown to reduce total serum cholesterol and may reduce myocardial infarction. The same review found no significant change in LDL cholesterol and triglycerides.[2] A 2021 review found that omega 6 supplements do not affect the risk of CVD morbidity and mortality.[3]

Dietary sources

Dietary sources of omega-6 fatty acids include:[4]

Vegetable oils

Vegetable oils are a major source of omega-6 linoleic acid. Worldwide, more than 100 million metric tons of vegetable oils are extracted annually from palm fruits, soybean seeds, rape seeds, and sunflower seeds, providing more than 32 million metric tons of omega-6 linoleic acid and 4 million metric tons of omega-3 alpha-linolenic acid.[5][6]

The nutritional values are expressed as percent (%) by mass of total fat.
Properties of vegetable oils[7][8]
TypeProcessing
treatment[9]
Saturated
fatty acids
Monounsaturated
fatty acids
Polyunsaturated
fatty acids
Smoke point
Total[7]Oleic
acid
(ω-9)
Total[7]α-Linolenic
acid
(ω-3)
Linoleic
acid
(ω-6)
ω-6:3
ratio
Avocado[10]11.670.652–66[11]13.5112.512.5:1250 °C (482 °F)[12]
Brazil nut[13]24.832.731.342.00.141.9419:1208 °C (406 °F)[14]
Canola[15]7.463.361.828.19.118.62:1238 °C (460 °F)[14]
Coconut[16]82.56.361.7175 °C (347 °F)[14]
Corn[17]12.927.627.354.715858:1232 °C (450 °F)[18]
Cottonseed[19]25.917.81951.915454:1216 °C (420 °F)[18]
Flaxseed/linseed[20]9.018.41867.853130.2:1107 °C (225 °F)
Grape seed 10.514.314.3  74.774.7very high216 °C (421 °F)[21]
Hemp seed[22]7.09.09.082.022.054.02.5:1166 °C (330 °F)[23]
Olive[24]13.873.071.310.50.79.814:1193 °C (380 °F)[14]
Palm[25]49.337.0409.30.29.145.5:1235 °C (455 °F)
Peanut[26]16.257.155.419.90.31819.661.6:1232 °C (450 °F)[18]
Rice bran oil2538.438.436.62.234.4[27]15.6232 °C (450 °F)[28]
High-oleic safflower oil[29]7.575.275.212.8012.8very high212 °C (414 °F)[14]
Sesame[30]14.239.739.341.70.341.3138:1
Soybean[31]partially hydrogenated14.943.042.537.62.634.913.4:1
Soybean[32]15.622.822.657.77517.3:1238 °C (460 °F)[18]
Walnut oil[33]unrefined9.122.822.263.310.452.95:1160 °C (320 °F)[34]
Sunflower[35]8.9963.462.920.70.1620.5128:1227 °C (440 °F)[18]
Cottonseed[36]hydrogenated93.61.50.60.20.31.5:1
Palm[37]hydrogenated88.25.70

List of omega-6 fatty acids

The chemical structure of linoleic acid, a common omega-6 fatty acid found in many nuts, seeds, and vegetable oils.
Common name Lipid name Chemical name
Linoleic acid (LA) 18:2 (n−6) all-cis-9,12-octadecadienoic acid
Gamma-linolenic acid (GLA) 18:3 (n−6) all-cis-6,9,12-octadecatrienoic acid
Calendic acid 18:3 (n−6) 8E,10E,12Z-octadecatrienoic acid
Eicosadienoic acid 20:2 (n−6) all-cis-11,14-eicosadienoic acid
Dihomo-gamma-linolenic acid (DGLA) 20:3 (n−6) all-cis-8,11,14-eicosatrienoic acid
Arachidonic acid (AA, ARA) 20:4 (n−6) all-cis-5,8,11,14-eicosatetraenoic acid
Docosadienoic acid 22:2 (n−6) all-cis-13,16-docosadienoic acid
Adrenic acid 22:4 (n−6) all-cis-7,10,13,16-docosatetraenoic acid
Osbond acid 22:5 (n−6) all-cis-4,7,10,13,16-docosapentaenoic acid
Tetracosatetraenoic acid 24:4 (n−6) all-cis-9,12,15,18-tetracosatetraenoic acid
Tetracosapentaenoic acid 24:5 (n−6) all-cis-6,9,12,15,18-tetracosapentaenoic acid

The melting point of the fatty acids increases as the number of carbons in the chain increases.[38]

See also

  • Cattle feeding
  • Essential fatty acid interactions
  • Essential nutrients
  • Inflammation
  • Linolenic acid
  • Lipid peroxidation
  • Olive oil regulation and adulteration
  • Omega-3 fatty acid
  • Omega-7 fatty acid
  • Omega-9 fatty acid
  • Ratio of fatty acids in different foods
  • Wheat germ oil

References

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  2. Hooper L, Al‐Khudairy L, Abdelhamid AS, Rees K, Brainard JS, Brown TJ, Ajabnoor SM, O'Brien AT, Winstanley LE, Donaldson DH, Song F, Deane KHO (2018). "Omega‐6 fats for the primary and secondary prevention of cardiovascular disease". Cochrane Database of Systematic Reviews. 11 (CD011094): CD011094. doi:10.1002/14651858.CD011094.pub4. PMC 6516799. PMID 30488422.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. Mazidi, M., Shekoohi, N., Katsiki, N., & Banach, M. (2021). "Omega-6 fatty acids and the risk of cardiovascular disease: insights from a systematic review and meta-analysis of randomized controlled trials and a Mendelian randomization study". Archives of Medical Science. 18 (2): 466–479. doi:10.5114/aoms/136070. PMC 8924827. PMID 35316920.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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  17. "Corn oil, industrial and retail, all purpose salad or cooking, fat composition, 100 g". US National Nutrient Database, Release 28, United States Department of Agriculture. May 2016. Retrieved 6 September 2017.
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Bibliography

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