Cyclic fatty acid monomers from dietary heated fats affect rat liver enzyme activity

Lamboni, Courdjo; Sébédio, Jean‐Louis; Perkins, E. G.

doi:10.1007/s11745-998-0256-0

Cited by 29 publications

(26 citation statements)

References 21 publications

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“…Although there exists some evidence that dietary CFAM have a negative impact on the development of fatty liver (Lamboni et al, 1998), evidence on the underlying mechanisms leading up to fat accumulation in the liver is still limited. To the best of our knowledge, this is the first study to assess the impact of CFAM combined with two different dietary oils on markers of hepatic steatosis in relative low‐fat diet fed rats.…”

Section: Discussionmentioning

confidence: 99%

Liver and plasma lipid changes induced by cyclic fatty acid monomers from heated vegetable oil in the rat

Mboma

Leblanc

Wan

et al. 2018

Food Science & Nutrition

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Cyclic fatty acid monomers (CFAM) generated through domestic or industrial heating of vegetable oils may alter liver enzymes and induce hepatomegaly and steatosis, but the underlying mechanisms are not clearly understood. This study aimed to assess the effects of CFAM on liver and plasma lipids and to determine whether these effects are modulated by dietary lipids. Thirty‐six (36) male Wistar rats were fed either of the four isoenergetic diets consisting of canola oil or soybean oil with/without 500 mg/100 g CFAM of total fat for 28 days. Rats fed CFAM had higher liver total lipids (p = 0.03) and triacylglycerols (TAG) (p = 0.02), but less hepatic phosphatidylcholine (p = 0.02) compared to those fed the non‐CFAM diets. CFAM did not alter liver phosphatidylethanolamine N‐methyltransferase (PEMT) activity and CTP: phosphocholine cytidylyltransferase (CT‐α) protein levels. Rats fed CFAM diets had higher levels of plasma total cholesterol (TC), VLDL + LDL cholesterol, higher ratio of TC to HDL cholesterol, and lower levels of HDL cholesterol compared with rats fed non‐CFAM diets (p < 0.05). Plasma alanine transaminase (ALT) was decreased with CFAM, but plasma insulin, glucose, and TAG did not vary among the four diet groups (p < 0.05). Rats fed canola oil and CFAM had higher plasma levels of aspartate transaminase (AST) and AST/ALT ratio compared with the other three diet groups. These results indicate that CFAM may provoke an accumulation of TAG in the liver related to a decrease in phosphatidylcholine (PC) levels, but the effect of CFAM on PC concentrations may not occur through impairment of the two main PC biosynthesis pathways.

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Section: Discussionmentioning

confidence: 99%

Liver and plasma lipid changes induced by cyclic fatty acid monomers from heated vegetable oil in the rat

Mboma

Leblanc

Wan

et al. 2018

Food Science & Nutrition

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“…This study shows that dietary oxidized oils reduce triglyceride concentrations in plasma and liver. Recent studies demonstrated that the activities of glucose-6-phosphate dehydrogenase (8) and other enzymes involved in the synthesis of fatty acids in the liver (13) are reduced by dietary lipid peroxidation products. Thus, reduced concentrations of triglycerides in plasma and liver might be caused by a reduced rate of lipogenesis.…”

Section: Tablementioning

confidence: 99%

“…On the other hand, this study as well as others (6,7,11,34) reported increased liver weights in animals fed oxidized oils. It has been shown that the enlargement of liver is largely due to a proliferation of endoplasmic reticulum, which is indicated by the induction of microsomal detoxifying enzymes (8,10). This also might explain the significant increase in phospholipid content in the liver and the increased ratio between phospholipids and cholesterol.…”

Section: Tablementioning

confidence: 99%

“…To study metabolic effects of these compounds, experiments with animals were carried out which in most cases used highly oxidized vegetable oils or fish oil (1-7) as well as isolated lipid peroxidation products (8). Those experiments exhibited some effects of oxidized oils on lipid metabolism, with alterations of tissue fatty acid compositions being observed (1)(2)(3)(4)(5)(6)(7).…”

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The effects of a dietary oxidized oil on lipid metabolism in rats

Eder

1999

Lipids

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This study was carried out to investigate the effects of a dietary oxidized oil on lipid metabolism in rats, particularly the desaturation of fatty acids. Two groups of rats were fed initially for a period of 35 d diets containing 10% of either fresh oil or thermally treated oil (150 degrees C, 6 d). The dietary fats used were markedly different for lipid peroxidation products (peroxide value: 94.5 vs. 3.1 meq O2/kg; thiobarbituric acid-reactive substances: 230 vs. 7 micromol/kg) but were equalized for their fatty acid composition by using different mixtures of lard and safflower oil and for tocopherol concentrations by individual supplementation with DL-alpha-tocopherol acetate. In the second period which lasted 16 d, the same diets were supplemented with 10% linseed oil to study the effect of the oxidized oil on the desaturation of alpha-linolenic acid. During the whole period, all the rats were fed identical quantities of diet by a restrictive feeding system in order to avoid a reduced food intake in the rats fed the oxidized oil. Body weight gains and food conversion rates were only slightly lower in the rats fed the oxidized oil compared to the rats fed the fresh oil. Hence, the effects of lipid peroxidation products could be studied without a distortion by a marked reduced food intake and growth. To assess the rate of fatty acid desaturation, the fatty acid composition of liver and heart total lipids and phospholipids was determined and ratios between product and precursor of individual desaturation reactions were calculated. Rats fed the oxidized oil had reduced ratios of 20:4n-6/18:2n-6, 20:5n-3/18:3n-3, 20:4n-6/20:3n-6, and 22:6n-3/22:5n-3 in liver phospholipids and reduced ratios of 20:4n-6/18:2n-6, 22:5n-3/18:3n-3, and 22:6n-3/18:3n-3 in heart phospholipids. Those results suggest a reduced rate of desaturation of linoleic acid and alpha-linolenic acid by microsomal delta4-, delta5-, and delta6-desaturases. Furthermore, liver total lipids of rats fed the oxidized oil exhibited a reduced ratio between total monounsaturated fatty acids and total saturated fatty acids, suggesting a reduced delta9-desaturation. Besides those effects, the study observed a slightly increased liver weight, markedly reduced tocopherol concentrations in liver and plasma, reduced lipid concentrations in plasma, and an increased ratio between phospholipids and cholesterol in the liver. Thus, the study demonstrates that feeding an oxidized oil causes several alterations of lipid and fatty acid metabolism which might be of great physiologic relevance.

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“…Some of these reactions lead to the formation of cyclic fatty acid monomers (CFAM), mainly from 18:3n-3 and 18:2n-6 (2)(3)(4). When fed to rats as a purified fraction, these CFAM are incorporated into cellular lipids (4), and those formed from linolenic acid (Ln) have been associated with several adverse effects such as poor growth and high mortality after birth (4), alteration of electrophysiological parameters as well as resistance to reoxygenation after hypoxia of heart cells in culture (5), and modification of some enzymatic activity in liver (6,7), intestine (8), or cultured endothelial cells (9).…”

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confidence: 99%

Effect of fatty acid positional distribution and triacylglycerol composition on lipid by‐products formation during heat treatment: III—Cyclic fatty acid monomers study

Martin

Lavillonnière

Nour

et al. 1998

J Americ Oil Chem Soc

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The influence of isomeric triacylglycerols (TG) containing 18:3n-3 and 18:2n-6 on the formation of cyclic fatty acid monomers (CFAM) after heat treatment was assessed. Diacid TG, containing linoleic acid (L) or linolenic acid (α-Ln) along with palmitic acid (P), and positioned either in the central position (PLP and PLnP, respectively), or in one of the two outer positions (PPL and PPLn, respectively) were synthesized. Monoacid TG of trilinolein and trilinolenin mixed with tripalmitin were also prepared. The CFAM formed after heating were analyzed after total hydrogenation. The results obtained with the model TG were compared to another model consisting of a canola oil and its randomized counterpart. In diacid TG, the location of α-Ln in the central position of the TG molecule (PLnP) greatly enhanced the formation of the CFAM upon heating at temperatures below 240°C. On the other hand, 18:3n-3 in monoacid TG (LnLnLn) was highly resistant to CFAM formation within the same range of temperatures (180-220°C). The TG structure, more than the TG composition, seemed to explain the differences in the CFAM formation between the original canola oil and its interesterified counterpart. Like α-Ln, 18:2n-6 was more prone to cyclization when attached at the central position of the model TG. Conversely, the influence of the TG composition on the cyclization rate was less important for L than for α-Ln. It was concluded that positioning the C18 polyunsaturated fatty acid in the central position of TG rendered the oils much more sensitive to the cyclization reaction upon heat treatment.

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Cyclic fatty acid monomers from dietary heated fats affect rat liver enzyme activity

Cited by 29 publications

References 21 publications

Liver and plasma lipid changes induced by cyclic fatty acid monomers from heated vegetable oil in the rat

Liver and plasma lipid changes induced by cyclic fatty acid monomers from heated vegetable oil in the rat

The effects of a dietary oxidized oil on lipid metabolism in rats

Effect of fatty acid positional distribution and triacylglycerol composition on lipid by‐products formation during heat treatment: III—Cyclic fatty acid monomers study

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