Journal Name:
Ann Nutr Metab

Article Title:
Replacement of margarine on Bread by Rapeseed and Olive Oils: Effects on Plasma Fatty Acid Composition and Serum Cholesterol

Date Written:
1993

Volume:
37

Number:

Page:
161

Author(s):
Sepp�nen-Laakso, T; Vanhanen, H.; Laakso, I.; Kohtam�ki, H.; Viikari, J.

Article:
In an earlier study, Seppanen-Laakso and co-workers assessed the effects of replacing butter with CO and a CO margarine on plasma fatty acid composition and serum cholesterol levels (1992. Br. J. Nutr. 69:639). They reported that ALA in CO can be synthesized into EPA. The substitution of butter with CO and CO margarine led to decreases in serum total and LDL-C without a reduction in HDL-C; results which would be expected to lower the risk of coronary heart disease. The present study was designed to determine whether CO and olive oil substitution would have similar effects in individuals who consume margarine rather than butter.

Plasma fatty acid composition and serum cholesterol were assessed in forty-three subjects. During the substitution period of 6 weeks, margarine on bread was replaced by water-oil emulsions (fat content of 65%) as CO (n=23) or OO (n=23). No other changes were made to the habitual diets. Eleven subjects served as the control group and consumed both butter and commercial margarine on bread. The mean amount of ALA derived from CO represented about 10.2% of the CO emulsion. The replacement of margarine on bread by these oils accounted, on average for 16% of the total fat and 7% of the total energy intake.

Following the substitution period, changes in the relative fatty acid composition of plasma PLs were closely related to dietary fatty acid intake. SFA decreased and MUFA increased significantly during the first 3 weeks of the CO diet. A significant dose-dependent rise in ALA and OA following the CO and the OO diets, respectively, was noted. The proportion of ALA significantly increased in PLs of subjects consuming the CO diet at 3 weeks and returned to baseline levels at 12 weeks. EPA levels were significantly elevated after 3 weeks in the group consuming the CO margarine. A negative correlation between changes in EPA and LA was noted at 3 weeks. In addition, a preferential incorporation of n-3 PUFA with a concomitant decrease in n-6 PUFA, into PLs was evident in the CO group. The negative relationship between these two families of PUFAs was found to be significant.

In the group consuming CO, serum cholesterol and LDL-C were significantly decreased only after the post-experimental period (at week 12). HDL-C and the HDL-C/TC ratio increased significantly during the first 3 weeks of the CO diet and remained elevated at 6 weeks. The OO diet decreased LDL-C significantly at 3 weeks and had no effect on HDL-C levels. Reductions in TC and LDL-C levels were the most pronounced among subjects whose baseline values were higher than 6.0 mmol/L. The decrease in TC and LDL-C levels and increase in the HDL-C/TC ratio during the first 3 weeks of CO feeding were significantly correlated with an increase in the PL content of ALA.

The results of this research support the earlier findings of these investigators and confirm that small amounts of CO can serve as a source of ALA which is rapidly converted into EPA, the precursor for anti-thrombotic eicosanoids. In addition, the CO diet did not result in persistent reductions in LA levels in PLs, as did the OO. The authors indicated that the LA content of the CO prevented potentially negative long term effects of decreases in the levels of LA in PLs. The authors concluded that the correlations noted between PL ALA and LDL-C and HDL-C/TC ratio suggests that ALA is of greater importance than MUFA when margarine is substituted by CO. From the results of this study, the beneficial effects of dietary CO as they relate to CHD reduction and prevention, also include its ability to increase HDL-C and the proportion of n-3 PUFAs, especially EPA, in plasma PLs., , , ,

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