Low amounts oftrans18 : 1 fatty acids elevate plasma triacylglycerols but not cholesterol and alter the cellular defence to oxidative stress in mice

Abstract

Trans fatty acids are found mainly in processed foods. It has been shown that when their intake is high, total cholesterol, LDL-cholesterol and triacylglycerols are elevated, while HDL-cholesterol decreases. To evaluate a possible effect of these compounds, even in low amounts, C57Bl/6J mice were fed for 7 weeks a diet containing 13·6 % energy as partially hydrogenated rapeseed oil-enriched diet (Trans diet). The Trans diet contained 3 % energy as trans 18 : 1 fatty acid (elaidic acid). Control mice were on an isologous diet containing native rapeseed oil (Rapeseed diet) in which trans fatty acids were undetectable. Total, free and HDL-cholesterol as well as reverse cholesterol transport did not change. However, plasma triacylglycerol and VLDL levels increased. Hepatic gene expression in the Trans v. Rapeseed diet were compared using quantitative RT-PCR. The Trans diet produced a 2-3-fold elevation in mRNA of fatty acid synthase and microsomal transfer protein mRNA, explaining (at least in part) the observed increase in triacylglycerols and VLDL. In addition, mice on the Trans diet developed a deficiency in plasma vitamin E accompanied by a higher concentration of F2-isoprostanes, indicative of increased oxidative stress. The 78 kDa glucose-related protein (GRP78) mRNA expression increased 3-4-fold in liver, suggesting that a response against apoptosis was provoked by lipid peroxidation.Trans fatty acids: Hepatic triacylglycerol production: Reverse cholesterol transport: Oxidative stress Trans fatty acids (TFA) are steric isomers of the common cis unsaturated fatty acids containing at least one double bond in the trans configuration. TFA are found in meat and dairy products at significant levels since they are intermediates in fatty acid b-oxidation, and also formed in the rumen by bacterial hydrogenation. But they are present at much higher levels in processed fried foods and cookies often made with hydrogenated vegetable oils (shortening). Evidence that use of TFA in food represents a risk for health has accumulated, and very recently a campaign has been launched by a US nutritional group to eliminate them from processed food recipes. TFA have already been cutdown in Denmark where guidelines issued by the government fix the maximal amount tolerated in foods. TFA intake has been associated with an increased risk of CHD. This correlated to increased plasma concentrations of total cholesterol, LDL-cholesterol, triacylglycerols, and decreased levels of HDL-cholesterol, which could explain their effect on CHD (Mensink & Katan, 1990;Ascherio et al. 1999). These biochemical alterations appear to be somewhat proportional to intake (Lichtenstein et al. 1999). However, most of these studies were done with rather high concentrations of TFA and little is known about the possible impact on health of lower dietary intake of TFA as observed in Mediterranean countries. A better understanding of the effect of low levels of TFA on plasma lipoproteins and other biomarkers of CHD risk would provide insight into better prevention ...

The α-linolenic acid content of flaxseed can prevent the atherogenic effects of dietary trans fat

“…Our laboratory's previous work has demonstrated that iTFAs dose-dependently initiate the atherogenic process (6). The source and dosage of TFA provided to the mice in this study [as well as our laboratory's previous work (6)] was similar in type and energetic load to previous clinical and experimental reports and to current human TFA consumption values (4,9,39). The diets providing elaidic acid rich, partially hydrogenated vegetable shortening in either a moderate (T) or high (HT) dose, provided 1.4 and 2.8% industrial source TFAs (iTFAs), representing 3.2 and 6.4% of caloric energy, respectively.…”

Elaidic Acid, a <b><i>Trans</i></b>-Fatty Acid, Enhances the Metastasis of Colorectal Cancer Cells

“…Following ingestion, EA is typically integrated in the plasma membrane of cells [9] . EA has also been shown to induce oxidative stress, for example, an EA rich diet caused oxidative stress in mice due to EA-induced reduction in plasma vitamin E levels [10] . EA can also be incorporated into triglycerides, cholesterol esters, and phospholipids as well as other long-chain fatty acids, such as OA, linoleic acid, and palmitic acid [11] .…”

Trans fatty acids exacerbate dextran sodium sulphate-induced colitis by promoting the up-regulation of macrophage-derived proinflammatory cytokines involved in T helper 17 cell polarization

“…It is also well known that TFAs can modify cellular functions by interacting with the hydrophobic regions of membrane proteins [34]. Furthermore, recent studies reported that TFAs might alter cell membrane permeability, eicosanoid production and gene expression [35][36][37]. Several interesting studies have reported on receptors for fatty acids.…”