The effect of fatty acid composition of rapeseed oil on plasma lipids and oxidative stability of low-density lipoproteins in cholesterol-fed hamsters

Abstract

We studied the effect of four rapeseed oils with different fatty acid profiles on parameters implicated in the pathogenesis of atherosclerosis in humans in a model experiment with hamsters. The hamsters were divided into seven groups and fed a semi‐synthetic, cholesterol‐enriched diet (5 g/kg diet) containing 15% of the fat in question for a period of six weeks. The following rapeseed oils were used: (1) conventional rapeseed oil (6% saturated fatty acids [SFA], 64% monounsaturated fatty acids [MUFA], 18% linoleic acid [LA], 9% α‐linolenic acid [ALA]), (2) linoleic acid‐rich rapeseed oil (6% SFA, 61% MUFA, 28% LA, 2% ALA), (3) oleic acid‐rich rapeseed oil (6% SFA, 74% MUFA, 11% LA, 5% ALA), (4) myristic acid‐rich rapeseed oil (11% myristic acid, 35% SFA, 44% MUFA, 14% LA, 5% ALA). Sunflower oil, olive oil and lard were used as control fats. The concentrations of the lipids in the plasma, in the lipoprotein fractions and in the liver, the fatty acid composition of various tissues, the tocopherol status and the susceptibility of low‐density lipoproteins (LDL) to in vitro‐oxidation were determined. The concentrations of total cholesterol found in the plasma and in the LDL fraction and the ratios of LDL to HDL were similar after feeding the four different types of rapeseed oil, sunflower oil and olive oil. Lard produced the highest concentrations of cholesterol in plasma and the LDL fraction and the highest ratio of LDL to HDL. Feeding conventional, oleic acid‐ and myristic acid‐rich rapeseed oils resulted in markedly lower ratios of arachidonic to eicosapentaenoic acid in the lipids of the liver and the erythrocytes. This is considered beneficial for the formation of eicosanoids. The lag‐time before the onset of peroxidation of the LDL lipids, induced by copper ions, was not statistically significant between the seven hamster groups suggesting that the susceptibility of LDL to lipid peroxidation was similar after feeding all types of fat. Considering all parameters obtained in the used hamster model it is obvious that all four rapeseed oils are at least as favourable as olive oil or sunflower oil.

Hypolipidaemic effects of potato protein and fish protein in pigs

“…Therefore, the density fraction ρ < 1.006 kg/l is denominated ‘VLDL + chylomicrons’. Plasma densities were adjusted by addition of sodium chloride and potassium bromide (Eder and Brandsch, 2002). Lipids from liver were extracted with a mixture of n ‐hexane and isopropanol (3:2, v/v) (Hara and Radin, 1978).…”

Conjugated Linoleic Acid Isomers Reduce Cholesterol Accumulation in Acetylated LDL‐Induced Mouse RAW264.7 Macrophage‐Derived Foam Cells

“…Aliquots of the lipid extracts were dried under nitrogen, and total lipids of the extracts were transmethylated with trimethylsulfonium hydroxide as recently described in detail [44]. In brief, fatty acid methyl esters (FAME) were separated by gas chromatography using a gas chromatographic system (Hp 5890; Hewlett Packard, Waldbronn, Germany) fitted with an automatic split injection system, a flame ionization detector and a FFAP fused silica capillary column (30 m 9 0.53 mm i.d.…”

Effect of linseed oil supplementation on concentrations of (n‐3) polyunsaturated fatty acids in liver phospholipids of rats fed diets containing either an oil rich in conjugated linoleic acids, sunflower oil or high‐oleic acid sunflower oil

“…; Machery and Nagel, Düren, Germany). Fatty acid methyl esters were identified by comparing their retention times with those of individual purified standards (Eder and Brandsch, 2002).…”