Comparison between High-PUFA and Low-PUFA Fats on Lipid Peroxidation and LDL Oxidation

Christine M Seppanen,A Saari Csallany,Hyejung Cho

doi:10.4236/fns.2013.45074

Abstract

This study was conducted to determine the effects of a low polyunsaturated fatty acid (PUFA) 21 diet versus a high-PUFA diet on lipid peroxidation and on low density and very low density lipoprotein (LDL + VLDL) oxidation in vivo. Rats were fed 10% beef tallow (BT) or 10% soybean oil (SO) diet for 21 weeks. Lipid peroxidation was measured by assessing urinary 24 excretions of secondary lipid peroxidation products, by HPLC and by measuring thiobarbituric acid reactive substances (TBARS) in liver tissue. Plasma LDL + VLDL in vivo oxidation was measured by conjugated diene concentration and TBARS; ex vivo resistance to copper-induced oxidation was also assessed. Total urinary aldehydes, twelve individual urinary aldehydes, and TBARS in the liver were significantly lower in the BT group compared to the SO group. Plasma LDL + VLDL was significantly more resistant to copper-induced ex vivo oxidation to the BT group compared to the SO group. However, in vivo plasma LDL + VLDL oxidation levels measured as conjugated dienes and by TBARS were not significantly different. In general, the low-PUFA BT diet appears to have a protective effect on in vivo lipid peroxidation compared to the high-PUFA diet, but not on in vivo plasma LDL + VLDL oxidation.

Highlights

Lipid peroxidation, the oxidative deterioration of polyunsaturated fatty acids (PUFA), proceeds through an autocatalytic free radical induced chain reaction [1,2,3], and this is associated with the loss of membrane PUFA and the formation of hydroperoxides, free radical intermediates, and numerous secondary lipid peroxidation products such as aldehydes and related carbonyl compounds [4]
The overall results indicate that the low-PUFA diet reduced in vivo lipid peroxidation as compared to the high-PUFA diet measured by urinary aldehydes excretion and thiobarbituric acid reactive substances (TBARS) in the liver
These results are in good agreement with our previous findings [33] that the consumption of a relatively high level of stearic acid from low-PUFA beef tallow (BT) resulted in the reduction of in vivo lipid peroxidation, as compared to consumption of a high level of linoleic acid from highPUFA soybean oil (SO)

Summary

Introduction

The oxidative deterioration of polyunsaturated fatty acids (PUFA), proceeds through an autocatalytic free radical induced chain reaction [1,2,3], and this is associated with the loss of membrane PUFA and the formation of hydroperoxides, free radical intermediates, and numerous secondary lipid peroxidation products such as aldehydes and related carbonyl compounds [4]. Lipid peroxidation can impair cell functions by altering macromolecules including proteins and nucleic acids [5]. The release of toxic aldehydic degradation products, byproducts of PUFA metabolism, could result in significant damage to cells present in the arterial walls and may be related to atherosclerotic lesions. During the process of LDL oxidation, PUFA undergo peroxidative decomposition, resulting in the formation of secondary lipid oxidation products such as aldehydes and ketones [12]. Factors that have been reported to affect the susceptibility of LDL to oxidation include antioxidant concentration [16,17,18,19,20,21] and fatty acid composition [22,23,24,25,26,27,28,29,30]

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