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There are multiple adverse effects of trans fatty acids (TFA) that are produced by partial hydrogenation (i.e., manufactured TFA), on CVD, blood lipids, inflammation, oxidative stress, endothelial health, body weight, insulin sensitivity, and cancer. It is not yet clear how specific TFA isomers vary in their biological activity and mechanisms of action. There is evidence of health benefits on some of the endpoints that have been studied for some animal TFA isomers, such as conjugated linoleic acid; however, these are not a major TFA source in the diet. Future research will bring clarity to our understanding of the biological effects of the individual TFA isomers. At this point, it is not possible to plan diets that emphasize individual TFA from animal sources at levels that would be expected to have significant health effects. Due to the multiple adverse effects of manufactured TFA, numerous agencies and governing bodies recommend limiting TFA in the diet and reducing TFA in the food supply. These initiatives and regulations, along with potential TFA alternatives, are presented herein.

AbstractThe chromatographic analysis of food products for trans isomers of monounsaturated fatty acids, which are harmful components, in the presence of an excess of useful cis isomers is considered as a complex problem of considerable current interest. The separation of substances by gas–liquid chromatography occurs in accordance with two mechanisms with different selectivity for geometric isomers based on adsorption on a flat surface, which gives an energy advantage to trans isomers, and distribution in the bulk phase, which leads to the stronger retention of cis isomers. The theoretical model proposed previously to explain the distribution of an adsorbate as its “absorption” by a stationary-phase macromolecule due to a conformational rearrangement in the course of nonspecific interaction was supplemented by polar interactions and hydrogen bonds. The factors influencing the selectivity of a phase for geometric isomers were considered. A theoretical analysis of the experimental data was carried out and the parameters of stationary phases required for increasing the separation selectivity of the trans and cis isomers of fatty acid esters were determined.

Dietary fatty acids are incorporated into atheromatous plaques mainly in the form of cholesterol esters. Physicochemical properties of the plaque (e. g. mechanical strength) depend on its fatty acid composition. Trans isomers of unsaturated fatty acids (TFA) are known to reduce the availability of fatty acid precursors for the synthesis of anticoagulant PG(1) and PG(3) prostaglandins. The present study was undertaken to determine the content of trans isomers in atheromatous plaques and to search for correlations between trans isomers in the plaque and adipose tissue. Atheromatous plaques were obtained from 31 patients who underwent surgery due to atherosclerotic stenosis of the abdominal aorta, iliac or femoral arteries. Fatty acids were extracted and separated as methyl esters using gas chromatography (GC) with an internal standard. Correlations were searched for with statistical methods, taking the level of significance as p < 0.05. We found spatial and positional isomers of sixteen- and eighteen-carbon fatty acids in plaques and adipose tissue, with elaidic acid (C18:1 trans-9) being the most abundant. Every plaque and adipose tissue sample contained linolelaidic acid (C18:2 trans-9 trans-12) which is derived exclusively from linoleic acid, as well as conjugated dienes of linoleic acid (CLA) produced during oxidative processes. The presence of trans isomers of fatty acids in the atheromatous plaque seems to be of relevance to plaque formation. Of much concern is the detection of elaidic and linolelaidic acids which adversely affect the physiologically important metabolism of eicosanoids. The TFA pool in adipose tissue has little effect on the amount of these acids in the atheromatous plaque. Apparently, the presence of TFA in atheromatous plaques is the result of processes taking place during plaque formation and maturation.

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.

There is increasing evidence to indicate that nutrition is an important factor involved in the onset and development of several chronic human diseases including cancer, cardiovascular disease (CVD), type II diabetes and obesity. Clinical studies implicate excessive consumption of medium-chain saturated fatty acids (SFA) and trans-fatty acids (TFA) as risk factors for CVD, and in the aetiology of other chronic conditions. Ruminant-derived foods are significant sources of medium-chain SFA and TFA in the human diet, but also provide high-quality protein, essential micronutrients and several bioactive lipids. Altering the fatty acid composition of ruminant-derived foods offers the opportunity to align the consumption of fatty acids in human populations with public health policies without the need for substantial changes in eating habits. Replacing conserved forages with fresh grass or dietary plant oil and oilseed supplements can be used to lower medium-chain and total SFA content and increase cis-9 18:1, total conjugated linoleic acid (CLA), n-3 and n-6 polyunsaturated fatty acids (PUFA) to a variable extent in ruminant milk. However, inclusion of fish oil or marine algae in the ruminant diet results in marginal enrichment of 20- or 22-carbon PUFA in milk. Studies in growing ruminants have confirmed that the same nutritional strategies improve the balance of n-6/n-3 PUFA, and increase CLA and long-chain n-3 PUFA in ruminant meat, but the potential to lower medium-chain and total SFA is limited. Attempts to alter meat and milk fatty acid composition through changes in the diet fed to ruminants are often accompanied by several-fold increases in TFA concentrations. In extreme cases, the distribution of trans 18:1 and 18:2 isomers in ruminant foods may resemble that of partially hydrogenated plant oils. Changes in milk fat or muscle lipid composition in response to diet are now known to be accompanied by tissue-specific alterations in the expression of one or more lipogenic genes. Breed influences both milk and muscle fat content, although recent studies have confirmed the occurrence of genetic variability in transcript abundance and activity of enzymes involved in lipid synthesis and identified polymorphisms for several key lipogenic genes in lactating and growing cattle. Although nutrition is the major factor influencing the fatty acid composition of ruminant-derived foods, further progress can be expected through the use of genomic or marker-assisted selection to increase the frequency of favourable genotypes and the formulation of diets to exploit this genetic potential.

Background/Objectives: Growing evidence indicates that trans-fatty acids (TFA) adversely affect cardiovascular health. As part of the World Health Organization (WHO) Scientific Update on TFA, we reviewed the evidence for effects of TFA consumption on coronary heart disease (CHD). Subjects/Methods: We searched Medline publications examining TFA consumption and CHD risk factors or outcomes, emphasizing results of studies in humans. We evaluated and synthesized evidence from both controlled feeding trials evaluating risk factors and long-term observational studies evaluating risk factors or clinical outcomes, each of which have complementary strengths and limitations, to enable the most robust and reliable inferences of effects. Results: The effects of TFA consumption on risk factors most consistently seen in both controlled trials and observational studies included adverse lipid effects (for example increased low-density lipoprotein cholesterol, decreased high-density lipoprotein cholesterol (HDL-C), increased total/HDL-C ratio), proinflammatory effects (for example increased tumor necrosis factor-α activity, increased interleukin-6, increased C-reactive protein) and endothelial dysfunction. These effects were most prominent in comparison with cis unsaturated fats; adverse effects on total/HDL-C and endothelial function were also seen in comparison with saturated fatty acids (SFA). TFA may also worsen insulin sensitivity, particularly among individuals predisposed to insulin resistance; possible effects on weight gain and diabetes incidence require further confirmation. Five retrospective case-control studies and four prospective cohort studies demonstrated positive associations between TFA consumption and CHD events. A meta-analysis of prospective studies indicated 24, 20, 27 and 32% higher risk of myocardial infarction (MI) or CHD death for every 2% energy of TFA consumption isocalorically replacing carbohydrate, SFA, cis monounsaturated fatty acids and cis polyunsaturated fatty acids, respectively. The differential effects of specific TFA isomers may be important but are less well established. The available evidence indicates that trans-18:1 and particularly trans-18:2 isomers have stronger CHD effects than trans-16:1 isomers. The limited data suggest that the experimental effects of ruminant and industrial TFA are similar when consumed in similar quantities, but very few persons consume such high levels of ruminant TFA, and observational studies do not support adverse CHD effects of ruminant TFA in amounts actually consumed. Conclusions: Controlled trials and observational studies provide concordant evidence that consumption of TFA from partially hydrogenated oils adversely affects multiple cardiovascular risk factors and contributes significantly to increased risk of CHD events. The public health implications of ruminant TFA consumption appear much more limited. The effects of specific TFA isomers require further investigation.

Because potentially harmful trans fatty acids (TFAs) should be eliminated from the diet, each country should have updated estimates of TFA content in food. The purpose of the study was to provide data on TFA content in pastry products commercialized in the Polish market. Products made using hydrogenated fats (as declared by manufacturers) were tested. Samples were acquired between April 2017 and July 2017. Extraction of fat from all pastries was carried out by the method of Folch et al. The fatty acid (FA) composition, especially TFA content in extracted fats, was determined by gas chromatography. Fat in the products was characterized by a high level of saturated fatty acid (SFA; ca. 42 g/100 g of FA), with the exception of one sample. A great diversity of total TFA content in fat of the products was found (0.1 to 13.5 g/100 g of FA). Of the products tested, 37.5% had TFAs in excess of 2%. Furthermore, partially hydrogenated fats were the source of TFAs in the analyzed products, as demonstrated by high content of elaidic acid. In addition, there was a trend of a decrease in the daily intake of TFAs of industrial origin with pastry products (0.14 g) compared with earlier studies. These results highlight the ongoing need for improvement in terms of trans isomer content in pastry products in Poland. This study confirms the importance of developing effective policies for reducing the TFA content of food.

This study aimed to evaluate the fatty acid composition, including the contents, of conjugated linoleic acid cis9trans11 C18:2 (CLA) and trans C18:1 and C18:2 isomers in hard cow, sheep, and goat cheeses found on the Polish market and to compare lipid quality indices in these cheeses. The gas chromatography method was used to determine the fatty acid profile. The study demonstrated various contents of cis9trans 11 C18:2 (CLA), trans C18:1, and C18:2 isomers and the values of lipid quality indices in the cheeses. Sheep and goat cheeses were richer sources of short-chain fatty acids (SCFA) (14.73 ± 2.55% and 14.80 ± 2.80%, respectively) than the cow cheeses (9.38 ± 0.87%). The cow cheeses had a significantly higher (p < 0.05) content of monounsaturated fatty acids (MUFA), the lowest n-6/n-3 ratio, and the highest content of fatty acids, inducing a desirable dietary effect in humans (DFA) compared to the sheep and goat cheeses. Significantly higher (p < 0.05) contents of polyunsaturated fatty acids (PUFA) were found in sheep cheeses. Goat cheeses had the highest n-3 PUFA content and the lowest values of the thrombogenicity index (TI) (2.67 ± 0.44) compared to the sheep and cow cheeses (3.14 ± 0.29 and 3.13 ± 0.13, respectively). The cow, sheep, and goat cheeses were characterized by similar values of the hypocholesterolemic/hypercholesterolemic (H/H) ratio. Sheep cheeses had the highest levels of cis9trans11 C18:2 (CLA) and the highest total content of trans C18:1 and trans C18:2 isomers. The research showed that sheep, cow, and goat cheeses offered various health benefits. The differences in fatty acid composition and the different values of the lipid quality indices found in the cheeses may be due to differences in both the composition of milk used to produce them and the cheese-making technology. Studies conducted by many authors have indicated that the feeding system of the ruminants has a significant impact on the quality and chemical composition of milk, as well as its applicability for cheese production.

Background Nutritional choices, which include the source of dietary fatty acids (FA), have an important significant impact on coronary artery disease (CAD). We aimed to determine on patients with CAD the relationships between Trans fatty acids (Trans FA) and different CAD associated parameters such as inflammatory and oxidative stress parameters in addition to Gensini score as a vascular severity index. Methods Fatty acid profiles were established by gas chromatography from 111 CAD patients compared to 120 age-matched control group. Lipid peroxidation biomarkers, oxidative stress, inflammatory parameters and Gensini score were studied. Results Our study showed a significant decrease of the antioxidant parameters levels such as erythrocyte glutathione peroxydase (GPx) and superoxide dismutase (SOD) activities, plasma antioxidant status (FRAP) and thiol (SH) groups in CAD patients. On the other hand, catalase activity, conjugated dienes and malondialdehyde were increased. Plasmatic and erythrocyte Trans FA were also increased in CAD patients compared to controls. Furthermore, divergent associations of these Trans FA accumulations were observed with low-density lipoprotein-cholesterol/ high-density lipoprotein-cholesterol (LDL-C/HDL-C) ratio, Apolipoprotein B (ApoB), lipid peroxidation parameters, high-sensitivity C Reactive Protein (hs-CRP), Interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α) and Gensini score. Especially, elaidic acid (C18:1 trans 9), trans C18:2 isomers and trans 11 eicosanoic acid are correlated with these parameters. Trans FA are also associated with oxidative stress, confirmed by a positive correlation between C20:1 trans 11 and GPx in erythrocytes. Conclusions High level of Trans FA was highly associated with the induction of inflammation, oxidative stress and lipoperoxidation which appear to be based on the vascular severity and might be of interest to assess the stage and progression of atherosclerosis. The measurement of these Trans FA would be of great value for the screening of lipid metabolism disorders in CAD patients.

Milk fat is a complex mixture of geometric and positional isomers of monounsaturated and polyunsaturated, including short-, long- and branch-chain fatty acids (FAs). There has been partial success to resolve this mixture of FAs using different GC temperature programs, or a combination of GC isothermal and temperature programs. To overcome the problem associated with overlapping isomers prior silver-ion separation was recommended. However, this procedure is time consuming and not practical for routine analysis. In addition, previous methods focused mainly on the trans and cis isomers of 18:1. The present method takes advantage of differences in the relative elution times between different types of FAs. The method involved analyzing each milk fat using the same highly polar 100-m capillary column and GC instrument, and conducting two separations using temperature programs that plateau at 175 and 150 °C. The relative shift among the geometric and positional isomers at these two temperature settings was enough to permit identification of most of the trans and cis 16:1, 18:1 and 20:1, the c/t-18:2 and the c/c/t-18:3 isomers found in milk fat. The identity of these FAs was confirmed by prior separation of the total fatty acid methyl esters (FAMEs) of milk fat using Ag⁺-SPE columns, and comparing the fractions to the total milk fat. The Ag⁺-SPE technique was modified to obtain pure saturated, trans- and cis-monounsaturated and diunsaturated FAMEs. By combining the results from these two separate GC analyses, knowing the elution order, it was possible to determine most of the geometric and positional isomers of 16:1, 18:1, 20:1, 18:2 and 18:3 without a prior silver-ion separation. Only few minor FAs could not be resolved, notable the conjugated linoleic acid isomers that still required the complimentary Ag⁺-HPLC separation. The two GC temperature programs have been successfully used to routinely analyze most FA isomers in total milk and beef fats in about 200 min without the use of prior silver-ion separations.