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PubMed2004

Identification and quantification of trans fatty acids in bakery products by gas chromatography-mass spectrometry after dynamic ultrasound-assisted extraction.

trans Fatty acids have been determined in 14 bakery products using derivatisation by ester formation, gas chromatography-mass spectrometry (GC-MS) for individual separation, identification and quantification following total fat isolation by dynamic ultrasound-assisted extraction (DUAE). The detection and quantification limits between 0.98 and 3.93 microg g(-1) and 3.23 and 12.98 microg g(-1), respectively, and the linear dynamic ranges between LOQs values and 12,000 microg g(-1) thus obtained, demonstrated the utility of the approach for this type of analysis thanks to the wide determination range and high information level it provides. The proposed extraction method--validated by comparison with the Folch reference method--drastically reduces the extraction time as compared with the reference method without degradation of the target analytes by ultrasound irradiation, as demonstrated in the subsequent quantification step. The overall method thus developed could be a valid alternative to the reference method as the present and foreseeable increased demand for the analysis of these analytes makes mandatory faster methods. The number of samples used support the validation process.

Food Analysis↗

PubMed2006

Intake of ruminant trans fatty acids in the Danish population aged 1-80 years.

OBJECTIVE: To estimate the intake of ruminant trans fatty acids (TFA) in the Danish population aged 1-80 years. DESIGN: Descriptive study. SUBJECTS: A sex- and age-stratified random sample drawn from the Danish Civil Registration System. A total of 3098 participants (51% female) aged 1-80 years were included. The participation was 66%. DIETARY INFORMATION: A 7-day dietary record. RESULTS: The estimated median intake of ruminant TFA was 1.4 g/day with the 80% central range being from 0.9 to 2.1 among children aged 1-6 years and 1.6 g/day (1.0-2.4) among children aged 7-14 years. The median TFA intake was 1.8 g/day (0.9-2.9) among adults aged 15-29 years and among adults aged 30-80 years. The intake expressed as percentage of energy intake was 0.8, 0.6, 0.7, and 0.7, respectively. Dairy products were the main source of ruminant TFA. CONCLUSIONS: The median intake of ruminant TFA in the Danish population aged 1-80 years is estimated to be 1.7 g/day (0.9-2.7), corresponding to 0.7% of energy intake (0.5-1.0), with dairy products being the main source of ruminant TFA. SPONSORSHIP: The Danish Heart Foundation (Grants 02-2-9-8-22010 and 03-2-9-4-22087) and the Female Researchers in Joint Action (FREJA) programme from the Danish Medical Research Council.

Adolescent↗

PubMed1993

Trans fatty acid content of human milk in Spain.

The C18 fatty acid fraction of 38 samples of mature human milk from Spanish women was analyzed using capillary gas chromatography. The average content of trans fatty acids found in these samples represented 0.95% of total fatty acids. This value is lower than the percentage found in human milk from other developed countries in which the consumption of hydrogenated fat is higher. Trans fatty acid content in human milk has been related to the types of fats and oils present in the diets of the nursing mothers. According to the results obtained in this survey, we can also conclude that the amount of trans forms in breast milk lipids is lower than the trans content found in infant formulas in Spain.

Adolescent↗

PubMedDate not supplied

Overview of methods for the determination of trans fatty acids by gas chromatography, silver-ion thin-layer chromatography, silver-ion liquid chromatography, and gas chromatography/mass spectrometry.

trans Isomers of naturally occurring cis-unsaturated fatty acids are produced when liquid vegetable oils or marine oils are partially hydrogenated to produce margarine, shortenings, and other hardened-fat products. Isomeric trans fatty acids are also formed in the intestinal tract of ruminants, and they appear in small amounts in dairy products and ruminant meat. Currently, satisfactory analyses for the fatty acid profiles of fats containing trans fatty acids are obtained by gas chromatography (GC) using capillary columns coated with highly polar cyanosilicone stationary phases. In capillary GC methods, the key limitation has been the incomplete separation of trans-monoenoic acid isomers from their cis isomers; however, recent reports have demonstrated that improvements in separation are attainable with the use of 100 m columns. In these columns, there is very little overlap of cis and trans isomers. More accurate trans fatty acid analyses can be obtained by coupling GC with either silver-nitrate thin-layer chromatography or silver-nitrate liquid chromatography.

Chromatography, Liquid↗

PubMed2003

Higher content of 18:1 trans fatty acids in subcutaneous fat of persons with coronarographically documented atherosclerosis of the coronary arteries.

AIM: To identify the total content of trans fatty acid (TFA) isomers and C18:1 trans isomers in subcutaneous fat samples from persons with atherosclerosis of the coronary arteries, as an indicator of dietary exposure. METHODS: Using capillary gas chromatography, the authors determined total content of TFA isomers and C18:1 trans isomers in the subcutaneous fat of 34 patients with ischemic heart disease who had undergone aortocoronary bypass surgery and in 46 patients with no sign of coronary disease. RESULTS: On average, the total TFAs in cardiac patients were 2.88 +/- 1.19% of all fatty acids, in noncardiac patients 2.56 +/- 0.89%. However, the difference is not statistically significant. The average concentration of C18:1 trans in cardiac patients (2.31 +/- 1.09%) was statistically significantly higher (p = 0.05) than in the noncardiac group (1.95 +/- 0.77%). CONCLUSIONS: The results obtained indicate a lower TFA load in comparison with previous studies in other countries. A higher concentration of 18:1 TFAs in the subcutaneous fat of patients with coronary disease might be an impulse to correct the dietary habits of this very high-risk population.

Adipose Tissue↗

PubMed1993

Isomeric trans fatty acids in the Spanish diet and their relationships with changes in fat intake patterns.

Eleven different groups of food products (total samples 378), representing about 90% of total fat intake in Spanish diet, were analysed by gas chromatography in order to determine their contents and variability of trans fatty acids. With official data of food consumption in Spain, trans fatty acid intake is calculated for recent decades and results are compared with data available from other countries. Mean intake in Spain obtained from this calculation is 2.4 g/person/day. This is lower than values for other food consumption models in which the major fats are of animal origin or industrially processed.

Chromatography, Gas↗

PubMed1997

Do trans fatty acids increase the risk of coronary artery disease? A critique of the epidemiologic evidence.

On the basis of metabolic and epidemiologic data it has been claimed that trans fatty acid intake causes coronary artery disease (CAD), with > or = 30,000 deaths/y in the United States and a considerably greater number of nonfatal cases. The metabolic evidence is still controversial; the epidemiologic evidence is reviewed here. In most studies the likelihood that CAD "caused" margarine use, rather than the reverse, was not excluded. Uncontrolled confounding (particularly confounding by indication) was ubiquitous. Selection bias conditional on margarine use was common. The projection of 30,000 deaths/y is not justified. If the metabolic evidence, when fully evaluated, is deemed to be suggestive, then the question of whether trans fatty acids are indeed harmful to human populations will be resolved only by means of a randomized controlled trial.

Coronary Disease↗

PubMed2005

Comparison of the acute response to meals enriched with cis- or trans-fatty acids on glucose and lipids in overweight individuals with differing FABP2 genotypes.

Trans-fatty acids have been implicated as a risk factor for cardiovascular disease and diabetes. In addition, a polymorphism at codon 54 (Ala54Thr) in the fatty acid-binding protein 2 (FABP2) gene has been suggested to modify an interaction between dietary fat and insulin sensitivity. We examined the postprandial metabolic profiles after meals enriched with C18:1trans- relative to a similar meal with C18:1cis-fatty acid in individuals who were either FABP2 Ala54 homozygotes or Thr54 carriers. Moderately overweight men and women ate 2 breakfast test meals, separated by 1 week, each providing 40% of their daily energy requirement and containing 50% of energy as fat. In one meal, 10% of energy was from C18:1trans, and in the other meal, the C18:1trans was replaced with C18:1cis. Metabolic parameters were assessed during an 8-hour period. Insulin and C-peptide levels increased more after the C18:1trans meal, and this was associated with a greater fall in free fatty acids. Postprandial glucose levels and oxidation of fatty acids and carbohydrate were not different between the 2 test meals. The Thr54 allele for FABP2 increased the rise in postprandial glucose but not triacylglycerols. Fractional triacylglycerol synthetic rates were higher after consumption of the C18:1trans meal relative to the C18:1cis meal only in Thr54 carriers. These data show that a single meal enriched with C18:1trans-fatty acids can significantly increase insulin resistance, and that in the presence of the FABP2 Thr54 allele, may contribute to increased partitioning of glucose to triacylglycerols and insulin resistance.

Adult↗

PubMed2005

Dietary trans-fatty acids alter adipocyte plasma membrane fatty acid composition and insulin sensitivity in rats.

The present study was designed to investigate the effects of dietary trans-fatty acids (TFA) present in Indian vanaspati (partially hydrogenated vegetable oils) in comparison with saturated fatty acids (SFA) on adipocyte plasma membrane fatty acid composition, fluidity, and insulin action. The effects of 3% energy (% en) TFA was studied at 2% and 4% en of linoleic acid (18:2 n-6). WNIN male weanling rats were divided into 4 groups and fed casein-based diet containing 10% groundnut oil control (CON), palmolein (SFA), blend of vanaspati and safflower oil (3% en TFA and 2% en 18:2 n-6, TFA-1), or blend of vanaspati and safflower oil (3% en TFA and 4% en 18:2 n-6, TFA-2) for 12 weeks. Compared with CON, rats fed TFA and SFA diets had high levels of fasting plasma insulin and triglycerides. Both TFA- and SFA-fed groups had low levels of arachidonic acid (20:4 n-6) in adipocyte plasma membrane phospholipids. However, adipocyte plasma membrane fluidity decreased only in TFA-fed rats. Norepinephrine-stimulated lipolysis was high, whereas the antilipolytic effect of insulin and insulin-stimulated glucose transport were low in the adipocytes of SFA- and TFA-fed rats. However, the extent of decrease in the antilipolytic effect of insulin and insulin-stimulated glucose transport was greater in TFA-fed rats. These findings suggest that diet providing approximately 10% en SFA (PUFA/SFA [P/S] ratio 0.2) decreased adipocyte insulin sensitivity in rats. In these diets, replacement of approximately 2% en SFA (16:0) and approximately 1% en monounsaturated fatty acid (18:1 cis) with TFA decreased adipocyte insulin sensitivity to a greater extent. However, increasing dietary 18:2 n-6 did not prevent or reduce the TFA-induced adipocyte insulin resistance.

Adipocytes↗

PubMed2005

Trans fatty acid derived phospholipids show increased membrane cholesterol and reduced receptor activation as compared to their cis analogs.

The consumption of trans fatty acid (TFA) is linked to the elevation of LDL cholesterol and is considered to be a major health risk factor for coronary heart disease. Despite several decades of extensive research on this subject, the underlying mechanism of how TFA modulates serum cholesterol levels remains elusive. In this study, we examined the molecular interaction of TFA-derived phospholipid with cholesterol and the membrane receptor rhodopsin in model membranes. Rhodopsin is a prototypical member of the G-protein coupled receptor family. It has a well-characterized structure and function and serves as a model membrane receptor in this study. Phospholipid-cholesterol affinity was quantified by measuring cholesterol partition coefficients. Phospholipid-receptor interactions were probed by measuring the level of rhodopsin activation. Our study shows that phospholipid derived from TFA had a higher membrane cholesterol affinity than their cis analogues. TFA phospholipid membranes also exhibited a higher acyl chain packing order, which was indicated by the lower acyl chain packing free volume as determined by DPH fluorescence and the higher transition temperature for rhodopsin thermal denaturation. The level of rhodopsin activation was diminished in TFA phospholipids. Since membrane cholesterol level and membrane receptors are involved in the regulation of cholesterol homeostasis, the combination of higher cholesterol content and reduced receptor activation associated with the presence of TFA-phospholipid could be factors contributing to the elevation of LDL cholesterol.

Animals↗

PubMed1999

Differential effects of individual trans fatty acid isomers on lipoprotein assembly and metabolism.

Recent findings indicate that certain (t-C18:1 delta 9) but not all (t-C16:1 delta 9 and t-C18:1 delta 11) trans fatty acid isomers influence intestinal lipoprotein secretion. A mechanism is suggested that appears to be sensitive to properties associated not only with geometric configuration but also with fatty acid chain length and double bond position. This mechanism could explain, in part, the conflicting results seen among studies investigating the effects of total dietary trans fatty acids on serum lipid and lipoprotein concentrations.

Fatty Acids↗

PubMed1998

Rapid determination of trans-fatty acids in human adipose tissue. Comparison of attenuated total reflection infrared spectroscopy and gas chromatography.

A rapid attenuated total reflection (ATR) infrared (IR) spectroscopy procedure was used for quantitating the levels of total trans-fatty acid methyl ester (FAME) derivatives in neat (without solvent) test samples isolated from human adipose tissue. This procedure requires no weighing of the laboratory sample. The single-beam spectrum of the trans-containing FAMEs was 'ratioed' against that of a reference material having only cis double bonds in order to obtain a symmetric absorption band at 966 cm(-1) on a horizontal background. A single-reflection ATR diamond cell that requires only about 1 microl of neat FAMEs was used. The average level of trans-fatty acids in human adipose tissue found by ATR (3.07+/-0.27%) was generally higher than that obtained by gas chromatography (2.59+/-0.20%). Reasons for such a difference are discussed.

Adipose Tissue↗

PubMed2004

Trans fatty acids in adipose tissue and the food supply are associated with myocardial infarction.

Metabolic studies have clearly shown that trans fatty acids (TFAs) elevate LDL and lower HDL cholesterol. Epidemiologic studies showed a relation between TFA intake and the risk of myocardial infarction (MI), but studies examining adipose tissue TFAs have not uniformly confirmed this. We performed a case control study examining both adipose tissue levels and dietary intake of TFAs and first MI. Between 1995 and 1997, 209 cases of first MI completed a 300-item FFQ and 79 had an adipose tissue biopsy; 179 matched controls completed the FFQ and 167 had a biopsy. During the course of the study (mid-1996), TFAs were eliminated from margarines sold in Australia. Cases biopsied before mid-1996 had greater levels of trans 18:1(n-9) (32% P < 0.03) and trans 18:1(n-11) (23%, P < 0.001) than controls biopsied before mid-1996. After June 1996, there were no differences between cases and controls in any of the adipose tissue TFAs measured. Logistic regression showed that trans 18:1(n-11) (P = 0.03) was an independent predictor of a first MI. Cases consumed 0.5 g/d (P = 0.002) more TFAs than controls. Subjects in the highest quintile of TFA intake had an OR for first MI of 2.1 (95% CI, 1.1-4.3), which was not independent of saturated fat intake. Apparent TFA intake from margarine was related to adipose tissue 18:1t[(n-9) and (n-10)] in 1995 (r = 0.66, 0.66, respectively). We conclude that TFAs in adipose tissue are associated with an increased risk of coronary artery disease and rapidly disappear from adipose tissue when not included in margarines.

Adipose Tissue↗

PubMed1980

Nutritional aspects of trans fatty acids. Note I. Their accumulation in tissue lipids of rats fed with normolipidic diets containing margarine.

The fatty acid composition of extracts from organs of rats fed with normolipidic diets-either olive oil or sunflower margarine-has been determined in order to evaluate the influence of alimentary lipids on the storage of fatty acids in the animals liver, kidney, heart, adipose tissue and brain. The data obtained clearly showed that elaidized feeds caused an increase of trans-fatty acids in all the organs, although in different relative amounts, unrelated with the increase of these geometric isomers in the diet. Moreover it was found that the administration of trans fatty acid rich diets influenced the accumulation of essential fatty acids in the organs.

Animals↗

PubMed1996

Trans fatty acids and cancer.

Despite a general lack of evidence for the carcinogenic effects of trans fatty acids, some recent research and popular media have suggested a possible association. The available scientific data do not support this relationship and are reviewed so as to put this issue in perspective.

Animals↗

PubMed2005

Preparation of spread oils meeting U.S. Food and Drug Administration Labeling requirements for trans fatty acids via pressure-controlled hydrogenation.

On July 11, 2003, the U.S. Food and Drug Administration (FDA) announced final regulations for trans fatty acid (TFA) labeling. By January 1, 2006, the TFA content of foods must be labeled as a separate line on the Nutrition Facts label. Products containing <0.5 g of TFA/14 g serving may be declared as zero. This paper describes technologies allowing compliance with TFA labeling requirements. Soybean oil was hydrogenated in a 2-L vessel at temperatures ranging from 120 to 170 degrees C at a hydrogen pressure of 200 psi. A commercial nickel-supported catalyst (25% Ni) was used at 0.02% Ni by weight of oil. The hydrogenated oils were characterized for fatty acid composition, solid fat content, and melting point. Compared to commercially processed soybean oil basestocks that typically contain approximately 40% TFA, those obtained at lower temperatures and higher pressures contain >56% less TFA. Basestocks prepared in the laboratory when blended with liquid soybean oil will yield spread oils meeting FDA labeling requirements for zero TFA, that is, <0.5 g of TFA/serving.

Food Handling↗

PubMed2002

Trans fatty acids in maternal diet may impair lipid biosynthesis in mammary gland of lactating rats.

Although trans fatty acids are known to influence essential fatty acid (EFA) metabolism and serum levels of lipids and lipoproteins, little is known about their effects on the metabolism of mammary glands (MGs) during lactation. In this study, 5 groups of lactating Wistar rats were fed semisynthetic diets containing 7% soy oil (control); 7% partially hydrogenated vegetable oil (7% PHVO); 13% PHVO +7% soy oil (13% PHVO); 5% PHVO +2% soy oil (5% PHVO), and 3.5% PHVO +3.5% soy oil (3.5% PHVO). Dams were killed on the 12th day of lactation. Weight, lipid content (LC), in vivo lipogenesis rate (LR) and activity of the lipogenic (ATP-citrate lyase and malic) enzymes were evaluated in the MGs. Maternal food intake, weight gain, and total MG weight were not found to be significantly different between the groups. The groups with 13, 7 and 5% PHVO presented a lower (p < 0.05) LR in MGs when compared to controls, whereas MG LC was higher in the 7 and 13% groups than in controls. The observed decrease in MG lipogenesis was accompanied by a diminution (p < 0.05) in the activities of ATP-citrate lyase and malic enzymes. These data indicate a potential impairment of lipid metabolism in the MG by trans isomers in lactating rats.

ATP Citrate (pro-S)-Lyase↗

PubMed1982

Effect of dietary trans fatty acids on cholinesterase and monoamine oxidase activities in different organs of rats.

The effect of trans fatty acids and essential fatty acid deficiency upon the activities of cholinesterase and monoamine oxidase in livers, hearts, brains and lungs of rats was studied. This study was performed using three groups of male albino rats. Two out of these three groups were fed essential fatty acid low diets containing 10% hydrogenated coconut oil (HCNO) or margarine stock (MS, partially hydrogenated soybean oil) while the third group was fed an adequate supply of essential fatty acids through a diet containing 10% corn oil (CO). In the group of rats fed HCNO the activities of cholinesterase and monoamine oxidase in their livers, hearts, brains and lungs were not significantly different from those of the control group fed CO. In the group of rats fed MS, the activity of cholinesterase was significantly decreased in the livers, hearts and brains, but not affected in the lungs, while the activity of monoamine oxidase was significantly decreased in the livers and hearts but not affected in the brains and lungs as compared to the control group fed CO. The levels of serum total lipids, total cholesterol and triglycerides were elevated in both groups of rats fed HCNO or MS than in the group fed CO, but this elevation was more highly significant in the group fed MS than in the group fed HCNO.

Animals↗