Eicosapentaenoic acid deficiency

There is some evidence that, in these patients, the interconversion between the polyunsaturated fatty acids is disturbed, which restricts the formation of eicosapentaenoic and docosahexaenoic acids. Such children are less likely to have been breastfed (breast milk contains these omega-3 fatty acids) they are more likely to suffer from allergies associated with essential fatty acid deficiency and also dry skin and hair and the membranes of the erythrocytes contain less omega-3 fatty acids compared with normal children. So far, the results of supplementation of the diet of these children with this disorder have not been conclusive. 

The conversion of oleoyl-CoA to linoleoyl-CoA is accomplished by some insects118 but does not take place in most animals. As a result of this biosynthetic deficiency, polyunsaturated fatty acids such as linoleic, linolenic, and the C20 arachidonic acid are necessary in the diet (Box 21-B). One essential function of linoleic acid is to serve as a precursor of prostaglandins and related prostanoids (Section D). Dietary linoleate is converted to its Co A derivative and then by sequential A6 desaturation,119 elongation, and then A5 desaturation, to the 20 4 (A5 8 11 14) arachidonoyl-CoA (Fig. 21-2, lower right). These acids are referred to as 0)6 because of the position of the last double bond. Linolenic acid can be converted in an analogous fashion to the CoA derivative of the 20 5 (A5 8 11 14 17 co6) eicosapentaenoic acid (EPA). The 22 6 docasahexaenoic acid (DHA Fig. 21-2) is apparently formed by elongation of the 22 5 acyl-CoA to 24 5, desaturation, transfer to a peroxisome or mitochondrion, and p oxidation to shorten the chain.953... 

In this chapter, our intent is to review the rapid changes that take place in the cerebral cortex of n-3 fatty acid-deficient monkeys when their diet is subsequently supplied with ample dietary n-3 fatty acids. Juvenile rhesus monkeys who had developed n-3 fatty acids deficiency since intrauterine life were repleted with a fish-oil diet rich in n-3 fatty acids, DHA, and 20 5n-3 (eicosapentaenoic acid, EPA). The fatty acid composition was determined for the lipid classes of plasma and erythrocytes and for the phospholipid classes and molecular species of frontal cortex samples obtained from serial biopsies and at the time of autopsy. From these analyses, the half-lives ofDHA and EPA in the phospholipids of plasma, erythrocytes, and cerebral cortex were estimated. The deficient brain rapidly regained a normal or even supernormal content ofDHA with a reciprocal decline in n-6 fatty acids, demonstrating that the fatty acids of the gray matter of the brain turn over with relative rapidity under the circumstances of these experiments. 

Bell JG, Tocher DR, MacDonald FM, Sargent JR. Diets rich in eicosapentaenoic acid and gamma-linolenic acid affect phospholipid fatty acid composition and production of prostaglandins El, E2, and E3 in turbot (Scophthalmus maximus), a species deficient in delta 5 fatty acid desaturase. Prostagland Leukotr Essent Fatty Acids 1995 53 279-86. 

Schneider JC, Livine A, Sukenik A, Roessler PG(1995) A mutant of Nannochloropsis deficient in eicosapentaenoic acid production. Phytochemistry (in press). 

Both CO-3 and co-6 FAs are essential FAs to higher animals including humans since aU mammals must obtain them through their diets (Simopoulos, 2010). A target co-6/co-3 FA raho of 1 1 to 2 1 is recommended for human nutrihon since the balance between co-6 and co-3 FA metabolites in the human brain is close to 1 1. Unfortunately, current Western diets are deficient in co-3 FAs and the CO-6/CO-3 FA ratio is 10-20 1. Therefore, more food ingredients rich in co-3 FA such as fish, flax, chia, walnuts, etc. are recommended. However, the conversion of ALA, the major co-3 FA in plant oils, to eicosapentaenoic (20 5 4i.i4,i7 EPA) and docosahexaenoic acids DHA), well-known essen-... 

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