REPLACEMENT OF MARGARINE ON BREAD BY RAPESEED AND OLIVE OILS - EFFECTS ON PLASMA FATTY-ACID COMPOSITION AND SERUM-CHOLESTEROL

The effects of zero erucic acid rapeseed oil and olive oil on plasma f atty acid composition and serum cholesterol were studied in margarine users (n = 46). The replacement of margarine on bread by these oils ac counted, on average, for 16% of the total fat and 7% of the total ener gy intake. Fatty acid analysis of total plasma indicated a dose-depend ent rise in alpha-linolenic (alpha-LLA) and oleic acid (OA) levels dur ing rapeseed and olive oil substitutions, respectively. Rapeseed oil s ubstitution increased the proportion of eicosapentaenoic acid (0.4%-un its, on average) in plasma phospholipids. A slight decrease in low-den sity lipoprotein cholesterol (LDL-C) and an increase in high-density l ipoprotein cholesterol (HDLC, 4.5%, p < 0.01) led to a significantly h igher HDL-C/total cholesterol (TC) ratio (1.9%-units). The results sug gest a marked competitive effect for alpha-LLA, not only among plasma phospholipid fatty acids, but also in the relationships with serum lip ids, since the changes in alpha-LLA, rather than in OA, were associate d with those in LDL-C and the HDL-C/TC ratio. No competitive action of polyunsaturated acids comparable to rapeseed oil was found during oli ve oil substitution. In contrast to the rapeseed oil diet, the reduced proportion of linoleic acid (LA) in plasma phospholipids was not rest ored; this may be unfavorable if the habitual intake of LA is low. How ever, the effects on LDL-C levels were beneficial: the concentration d ecreased by 5.9% (p < 0.01), correlating inversely with the increase i n OA. In addition, the concentration of HDL-C remained unchanged durin g olive oil substitution.