Omega-3 fatty acids, conversion

Emken, E.A. (1995) Influence of linoleic acid on conversion of linolenic acid to omega-3 fatty acids in humans, in Proceedings from the Scientific Conference on Omega-3 Fatty Acids in Nutrition, Vascular Biology, and Medicine. American Heart Association, Dallas, Texas, USA, pp. 9-18. 

Omega-3 fatty acids are long-chain polyunsaturated fatty acids. The parent fatty acid of this group is alpha-linolenic acid, an essential fatty acid that the body is unable to synthesize alpha-linolenic acid can be converted in the body to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In animals and man, these acids reduce the production of several compounds that are involved in inflammation and thrombosis, such as eicosanoids (prostaglandins, thromboxanes, prostacyclin, and leukotrienes) and cytokines (interleukin II-l) (1). The extent of the conversion of alpha-linolenic acid to EPA and DHA is unclear. The conversion process appears to be inhibited by a high intake of linoleic acid, another essential fatty acid (2). In addition, alpha-linolenic acid is found in dark green vegetables and the oils of certain nuts and seeds, especially rape seeds and soya beans. 

With a deficiency in linolenic acid (18 3oo3) (but not in linoleic acid), there is a decline in DHA (22 6co3) in the retina and brain, as revealed in studies with rodents and monkeys. With deficiency in only linolenic acid (omega-3), there is also an increase in conversion of the available linoleic acid (omega-6) to produce elevated levels of 22-carbon omega-6 fatty acids (Craig-Schmidt et ah, 1996 Innis et al, 1994). Deficiency in only linolenic acid results in altered learning behaviors and a decreased visual sense. 

Flaxseed This is another source of Omega-3 fatty acids, and it can be a good addition to your diet, or a substitute for fish and fish oil. Although flaxseed doesn t contain the essential Omega-3 DHA and EPA, as fish oil does, your body can theoretically convert the elements of flaxseed oil into these other EFAs. However, some people s bodies have trouble making this conversion, rendering flaxseed oil slightly less effective than fish/fish oil for some people, so I still recommend fish oil over flaxseed oil if possible. 

Pereira, S.L., Leonard, A.E., Huang, Y.S., Chuang, L.T., and Mukeiji, P. 2004. Identification of two novel microalgal enzymes involved in the conversion of the omega-3-fatty acid, eicosapentaenoic acid, into docosahexaenoic acid. Biochem. J. 384, 357-366. 

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

Identification and characterization of the CYP52 family of Candida tropicalis ATCC 20336, important for the conversion of fatty acids and alkanes to alpha, omega-dicarboxylie acids. Appl Environ Microbiol 69 5983-5991... 

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