Lipids

, Volume 34, Supplement 1, pp S1–S3 | Cite as

Essentiality of fatty acids

Abstract

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.

Abbreviations

DHA

docosahexaenoic acid

n-6 DPA

n-6 docosapentaenoic acid

EPA

eicosapentaenoic acid

PUFA

polyunsaturated fatty acid(s)

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Copyright information

© AOCS Press 1999

Authors and Affiliations

  1. 1.Department of Biochemistry, College of MedicineUniversity of IowaIowa City

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