[Diet and coronary disease]

The build up of cholesterol in the atheromas is caused by, among other things, a disequilibrium of certain plasmatic lipoproteins. Food components which modify the levels of these lipoproteins can be considered as "atherogenic". Other components influence platelet activity and can be considered "thrombogenic". The saturated fatty acids, C-12, C14 and C-16, are atherogenic because they increase LDL plasmatic levels when consumed in large quantities. Estearic acid would not be included in this group because it is easily transformed into oleic acid in the organism. However, all the above acids are considered thrombogenic insofar that they alter the permeability of the platelet membrane. The most common monounsaturated fatty acid (MUFA) in our diet is oleic. When this is replaced by saturated fat, the plasmatic levels of LDL fall while those of HDL remain constant or even increase. In addition oleic acid is less thrombogenic than saturated fatty acids. The substitution of saturated fat by PUFA, n-6, lowers LDL levels and also HDL levels if these fatty acids are consumed in quantity. Their richness in double bound chains means that they are not very thrombogenic, although the resultant LDL are easily oxidized and therefore very atherogenic. When saturated fat is replaced by n-3 fatty acids the effect on LDL and HDL are variable, and there is a substantial decrease in VLDL. These fatty acids are strongly antithrombotic and antiatherogenic and also reduce the inflammatory reaction due to the decreased formation of eicosanoides derived from arachidonic acid and the formation of eicosapentenoic acid derivatives.(ABSTRACT TRUNCATED AT 250 WORDS)