Essentiality of fatty acids


All fatty acids have important functions, but the term “essential” is applied only to those polyunsaturated fatty acids (PUFA) that are necessary for good health and cannot be completely synthesized in the body. The need for arachidonic acid, which is utilized for eicosanoid synthesis and is a constituent of membrane phospholipids involved in signal transduction, is the main reason why the n-6 class of PUFA are essential. Physiological data indicate that n-3 PUFA also are essential. Although eicosapentaenoic acid also is a substrate for eicosanoid synthesis, docosahexaenoic acid (DHA) is more likely to be the essential n-3 constituent because it is necessary for optimal visual acuity and neural development. DHA is present in large amounts in the ethanolamine and serine phospholipids, suggesting that its function involves membrane structure. Because the metabolism of n-6 PUFA is geared primarily to produce arachidonic acid, only small amounts of 22-carbon n-6 PUFA are ordinarily formed. Thus, the essentiality of n-3 PUFA may be due to their ability to supply enough 22-carbon PUFA for optimal membrane function rather than to a unique biochemical property of DHA.

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docosahexaenoic acid

n-6 DPA:

n-6 docosapentaenoic acid


eicosapentaenoic acid


polyunsaturated fatty acid(s)


  1. 1.

    Connor, W.E., Neuringer, M., and Reisbeck, S. (1992) Essential Fatty Acids: The Importance of n-3 Fatty Acids in the Retina and Brain,Nutr. Rev. 50, 21–29.

    PubMed  CAS  Article  Google Scholar 

  2. 2.

    Uauy, R.D., Birch, E.E., Birch, D.G., and Peirano, P. (1992) Visual and Brain Function Measurements in Studies of ω-3 Fatty Acid Requirements in Infants,J. Pediatr. 120s, 168–180.

    Google Scholar 

  3. 3.

    Smith, W.L., Borgeat, P., and Fitzpatrick, F.A. (1991) The Eicosanoids: Cyclooxygenase, Lipoxygenase, and Epoxygenase Products, inBiochemistry of Lipids, Lipoproteins and Membranes (Vance, D.E., and Vance, J., eds.), Elsevier, Amsterdam, pp. 297–325.

    Google Scholar 

  4. 4.

    Dudley, D.T., Macfarlane, D.E., and Spector, A.A. (1987) Depletion of Arachidonic Acid from GH3 Cells,Biochem. J. 246, 669–680.

    PubMed  CAS  Google Scholar 

  5. 5.

    Downing, D.T. (1992) Lipid and Protein Structures in the Permeability Barrier of Mammalian Epidermis,J. Lipid Res. 33, 301–313.

    PubMed  CAS  Google Scholar 

  6. 6.

    Yerram, N.R., Moore, S.A., and Spector, A.A. (1989) Eicosapentaenoic Acid Metabolism in Brain Microvessel Endothelium: Effect on Prostaglandin Formation,J. Lipid Res. 30, 1747–1757.

    PubMed  CAS  Google Scholar 

  7. 7.

    Yerram, N.R., and Spector, A.A. (1989) Effects of Omega-3 Fatty Acids on Vascular Smooth Muscle Cells: Reduction in Arachidonic Acid Incorporation into Inositol Phospholipids,Lipids 24, 594–602.

    PubMed  Article  CAS  Google Scholar 

  8. 8.

    Williard, D.E., Kaduce, T.L., Harmon, S.D., and Spector, A.A. (1998) Conversion of Eicosapentaenoic Acid to Chain-Shortened Omega-3 Fatty Acid Metabolites by Peroxisomal Oxidation,J. Lipid Res. 39, 978–986.

    PubMed  CAS  Google Scholar 

  9. 9.

    Yorek, M.A., Bohnker, R.R., Dudley, D.T., and Spector, A.A. (1984) Comparative Utilization of n-3 Polyunsaturated Fatty Acids by Cultured Human Retinoblastoma Cells,Biochim. Biophys. Acta 795, 277–285.

    PubMed  CAS  Google Scholar 

  10. 10.

    Dudley, D.T., and Spector, A.A. (1986) Inositol Phospholipid Arachidonic Acid Metabolism in GH3 Pituitary Cells,Biochem. J. 236, 235–242.

    PubMed  CAS  Google Scholar 

  11. 11.

    Applegate, K.R., and Glomset, J.A. (1991) Effect of Acyl Chain Unsaturation on the Conformation of Model Diacylglycerols: a Computer Modeling Study,J. Lipid Res. 32, 1635–1644.

    PubMed  CAS  Google Scholar 

  12. 12.

    Hyman, B.T., and Spector, A.A. (1982) Choline Uptake in Cultured Human Y79 Retinoblastoma Cells: Effects of Polyunsaturated Fatty Acid Compositional Modifications,J. Neurochem. 38, 650–656.

    PubMed  Article  CAS  Google Scholar 

  13. 13.

    Yorek, M.A., Hyman, B.T., and Spector, A.A. (1983) Glycine Uptake by Cultured Human Y79 Retinoblastoma Cells: Effect of Changes in Phospholipid Fatty Acyl Unsaturation,J. Neurochem. 40, 70–78.

    PubMed  Article  CAS  Google Scholar 

  14. 14.

    Yorek, M.A., Strom, D.K., and Spector, A.A. (1984) Effect of Membrane Polyunsaturation on Carrier-Mediated Transport in Cultured Retinoblastoma Cells: Alterations in Taurine Uptake,J. Neurochem. 41, 809–815.

    Article  Google Scholar 

  15. 15.

    Poling, J.S., Karanian, J.W., Salem, N., Jr., and Vicini, S. (1995) Time- and Voltage-Dependent Block of Delayed Rectifier Potassium Channels by Docosahexaenoic Acid,Molec. Pharmacol. 47, 381–390.

    CAS  Google Scholar 

  16. 16.

    Litman, B.J., and Mitchell, D.C. (1996) A Role for Phospholipid Polyunsaturation in Modulating Membrane Protein Function,Lipids 31, S–193-S–197.

    Google Scholar 

  17. 17.

    North, J.A., Spector, A.A., and Buettner, G.R. (1994) Cell Fatty Acid Composition Affects Free Radical Formation During Lipid Peroxidation,Am. J. Physiol. 267, C177-C188.

    PubMed  CAS  Google Scholar 

  18. 18.

    Jump, D.B., Clarke, S.D., Thelen, A., Liimatta, M., Ren, B., and Badin, R. (1996) Dietary Polyunsaturated Fatty Acid Regulation of Gene Expression,Prog. Lipid Res. 35, 227–241.

    PubMed  Article  CAS  Google Scholar 

  19. 19.

    Rotstein, N.P., Aveldano, M.I., Barrantes, F.J., Roccamo, A.M., and Politi, L.E. (1997) Apoptosis of Retinal Photoreceptors During Developmentin vitro: Protective Effect of Docosahexaenoic Acid,J. Neurochem. 69, 504–513.

    PubMed  CAS  Article  Google Scholar 

  20. 20.

    Sprecher, H., Luthria, D.L., Mohammed, B.S., and Baykousheva, S.P. (1995) Reevaluation of the Pathways for the Biosynthesis of Polyunsaturated Fatty Acids,J. Lipid Res. 36, 2471–2477.

    PubMed  CAS  Google Scholar 

  21. 21.

    Moore, S.A., Yoder, E., Murphy, S., Dutton, G.R., and Spector, A.A. (1991) Astrocytes, Not Neurons, Produce Docosahexaenoic Acid (22:6n-3) and Arachidonic Acid (20:4n-6),J. Neurochem. 56, 518–524.

    PubMed  Article  CAS  Google Scholar 

  22. 22.

    Spector, A.A., and Moore, S.A. (1992) Role of Cerebromicrovascular Endothelium and Astrocytes in Supplying Docosahexaenoic Acid to the Brain, in:Essential Fatty Acids and Eicosanoids (edited by Sinclair, A., and Gibson, R.) American Oil Chemists’ Society, Champaign, pp. 100–103.

    Google Scholar 

  23. 23.

    Zhang, H., Hamilton, J.H., Salem, N. Jr., and Kim, H.-Y. (1998) n-3 Fatty Acid Deficiency in the Rat Pineal Gland: Effects on Phospholipid Molecular Species Composition and Endogenous Levels of Melatonin and Lipoxygenase Products, J.Lipid Res. 39, 1397–1403.

    PubMed  CAS  Google Scholar 

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Correspondence to Arthur A. Spector.

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Spector, A.A. Essentiality of fatty acids. Lipids 34, S1–S3 (1999).

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  • Arachidonic Acid
  • Essential Fatty Acid
  • Docosahexaenoic Acid
  • Docosapentaenoic Acid
  • Retinoblastoma Cell