Effects of a monounsaturated rapeseed oil and a polyunsaturated sunflower oil diet on lipoprotein levels in humans.

Abstract

The effects of high oleic acid rapeseed oil compared with polyunsaturated fats on serum lipoprotein levels are largely unknown. Therefore, we fed 30 women and 29 men a baseline diet rich in saturated fat, which was followed by a diet rich in high oleic and low erucic acid rapeseed oil (total energy content of fat, 38%; saturates, 12.4%; monounsaturates, 16%; n-6 polyunsaturates, 6%; and n-3 polyunsaturates, 2%) and one rich in sunflower oil (total energy content of fat, 38%; saturates, 12.7%; monounsaturates, 10%; n-6 polyunsaturates, 13%; and n-3 polyunsaturates, 0%). The oils were incorporated into mixed natural diets that were dispensed in a random order for 3.5 weeks each in a blinded crossover design. The diet composition was confirmed by analysis of duplicate diets. Both test diets reduced serum total cholesterol (TC) and low density lipoprotein (LDL) cholesterol levels from baseline, the monounsaturated rapeseed oil diet more than the polyunsaturated sunflower oil diet (TC: -15% versus -12%, p<0.01; LDL cholesterol: -23% versus -17%, p<0.0l). Very low density lipoprotein (VLDL) cholesterol and total, VLDL, and LDL triglyceride levels were lower during the sunflower oil diet compared with the rapeseed oil diet Total high density lipoprotein (HDL) cholesterol levels remained unchanged by both diets. The consumption of rapeseed oil resulted in a more favorable HDLj to LDL cholesterol ratio (0.43±0.19 versus 0J9±0.18, /?<0.01) and an apolipoprotein A-I to B ratio (3.0±1.4 versus 2.4± 1.6,p<0.001) than did the sunflower oil. Our results suggest that substitution by high oleic acid rapeseed oil of saturated fats strongly affects LDL metabolism, whereas substitution by polyunsaturated sunflower oil affects both VLDL and in addition to LDL. (Arteriosclerosis and Thrombosis 1992;12:50-57)

A diet containing rapeseed oil-based fats does not increase lipid peroxidation in humans when compared to a diet rich in saturated fatty acids

“…Effects on serum lipids, lipoproteins, and apolipoproteins are in line with earlier intervention studies with rapeseed oil (McDonald et al, 1989;Wardlaw et al, 1991;Valsta et al, 1992;Nydahl et al, 1994). Even with the relatively high fat content of the test diets, we found lower total and LDL cholesterol levels, apo B concentrations, and LDL=HDL ratios and no differences in HDL cholesterol levels after the RO diet compared to the SAT diet.…”

“…This development may lead to an increased dietary intake of MUFAs and PUFAs, especially a-linolenic acid (18:3 n-3). Several intervention studies with rapeseed oil-rich diets have shown favourable effects on the blood lipid profile in healthy volunteers (McDonald et al, 1989;Wardlaw et al, 1991;Valsta et al, 1992;Nydahl et al, 1994) and in hyperlipidemic patients (Lichtenstein et al, 1993;Gustafsson et al, 1994;Nydahl et al, 1995). In these studies, serum levels of total and low-density lipoprotein (LDL) cholesterol were reduced, while serum levels of triglycerides and highdensity lipoprotein (HDL) cholesterol remained unchanged.…”

“…However, epidemiological studies investigating effects of dietary monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) on the outcome of CHD are less conclusive (Caggiula & Mustad, 1997). Several intervention studies have demonstrated that the lipoprotein profile could be improved by substituting MUFA and PUFA for SAFA (McDonald et al, 1989;Wardlaw et al, 1991;Valsta et al, 1992;Nydahl et al, 1994). However, intervention studies with PUFA-rich diets have also shown that the susceptibility of lipoproteins to oxidation was increased and that very high intakes of PUFAs may carry nonfavourable effects on the development of atherosclerosis (Tsimikas & Reaven, 1998;Eritsland, 2000).…”

The effect of a low-fat, high-carbohydrate diet on serum high density lipoprotein cholesterol and triglyceride

“…In those with average or moderately elevated cholesterol concentrations few studies involving natural foods have been conducted outside of metabolic wards; and when they have, participants have been provided with prepared foods (Mensink & Katan, 1989;Ginsberg et al, 1990;Valsta et al, 1992;Wahrburg et al, 1992;Lichtenstein et al, 1993) or intensive dietary counselling (Ehnholm et al, 1984). A strength of the present study is that it was conducted under normal living conditions, and apart from simple dietary guidelines, subjects were free to select and prepare their own foods.…”

Effects of canola, corn, and olive oils on fasting and postprandial plasma lipoproteins in humans as part of a National Cholesterol Education Program Step 2 diet.

“…More recently, a number of investigators have studied the differential effects of polyunsaturated and monounsaturated fatty acids on plasma lipoproteins and have reported that the replacement of saturated fat with either class of fatty acids resulted in the lowering of LDL-C concentrations. 13 - 28 Moreover, some investigators have noted that the monounsaturated fatty acidrich diets caused less reduction in HDL-C levels than the polyunsaturated fatty acid-rich diets, while other investigators have not observed such differences. 1328 Differences in study results may relate to the total fat content of the diet as well as the type of subjects studied.…”