Dietary fatty acids, serum lipids, platelet biochemistry and function.
Dietary fatty acids of the n-6 mainly linoleic acid (LA) series, and of the n-3, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) series both reduce plasma cholesterol levels and platelet responses to aggregating agents. The potency of n-3 fatty acids, which are present in relatively high concentrations in fish oils, is at least one order of magnitude greater than that of LA. The effects of fish oils appear to be related to the incorporation of EPA into plasma lipoproteins and cell phospholipid pools, thus modulating metabolic processes within specific lipid pools. Inhibition of platelet function and modifications of the activity of other blood cells, such as leukocytes, is attributed to interference with the eicosanoid system. Competition of EPA with arachidonic acid (AA) for the oxygenases and/or generation of less active metabolites from this precursor are the major mechanisms of action. Feeding studies in experimental animals indicate that exogenously administered n-3 fatty acids undergo distribution among the major plasma lipid classes and platelet phospholipids quite different to that of endogenous AA. In addition, the generation of inositolphosphates by stimulated platelets is decreased by dietary n-3 fatty acids in a manner independent of the effects on the eicosanoid system. It appears that polyunsaturated fatty acids (PUFA) of the n-6 and n-3 series are differently handled in various lipid pools and that early steps of cell activation, in addition to the generation of eicosanoids, are affected by dietary fatty acids. This indicates that fatty acids modulate key steps in the regulation of cell function and biochemistry.(ABSTRACT TRUNCATED AT 250 WORDS)
Galli
C
C
Institute of Pharmacological Sciences, University of Milan, Italy.
Mosconi
C
C
Medini
L
L
Tremoli
E
E
D001161:Arteriosclerosis / Q000097:blood / Q000517:prevention & control*; D001792:Blood Platelets / Q000502:physiology*; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage*; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood / Q000517:prevention & control*; D008055:Lipids / Q000097:blood*; D010974:Platelet Aggregation
D005231:Fatty Acids, Unsaturated; D008055:Lipids