Effects Of Trans Fatty Acids Research Articles

Effects of trans fatty acids on glucose homeostasis: a meta-analysis of randomized, placebo-controlled clinical trials

Although evidence from cohort studies has suggested that trans fatty acid (TFA) consumption may be associated with insulin resistance and diabetes, randomized placebo-controlled trials (RCTs) have yielded conflicting results. In a meta-analysis, we combined all available RCTs that examined the role of TFA intake on glucose homeostasis. A systematic review of PubMed was performed, and a total of 7 RCTs were included in the meta-analysis. Primary outcomes were glucose and insulin concentrations. Secondary outcomes were total, LDL-, and HDL-cholesterol and triglyceride concentrations. The pooled effect size (ES) was calculated through fixed- and random-effects meta-analyses. The potential existence of publication bias was evaluated by using funnel-plot analysis. Metaregression analysis was performed to evaluate for potential dose-response relations between the ES of outcomes and TFA intake. Increased TFA intake did not result in significant changes in glucose or insulin concentrations. Increased TFA intake led to a significant increase in total and LDL-cholesterol [ES (95% CI): 0.28 (0.04, 0.51) and 0.36 (0.13, 0.60), respectively] and a significant decrease in HDL-cholesterol concentrations [ES (95% CI): -0.25 (-0.48, -0.01)]. Our analysis also showed the absence of publication bias and any dose-response relations between the ES and TFA intake. Increased TFA intake does not result in changes in glucose, insulin, or triglyceride concentrations but leads to an increase in total and LDL-cholesterol and a decrease in HDL-cholesterol concentrations. There is no evidence to support a potential benefit of the reduction of dietary TFA intake on glucose homeostasis.

Trans fatty acids effect on some serum enzymes and immunological parameters in Wistar albino rats

The effect of trans fatty acids on some serum enzymes and immunological parameters in male albino Wistar rats was evaluated in this study. Fifty (50) male Wistar albino rats weighing between 100-140g were divided into five groups of ten rats each. The animals were fed varying proportions of trans fatty acids (15% and 25%) respectively using margarine and thermoxidised palm oil as sources.The control received palletized grower’s feed. The feeding experiment lasted for eight (8) weeks after which the animals were sacrificed and sera collected for analyses. Results showed significant decrease/increase in levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) respectively.CD4+ levels and basophils count were increased in the test groups except group 3 compared to the controls. Lymphocytes showed significant decreases (P<0.05) in all the test groups except group 3 when compared to the control. Our findings did not reveal probable hepatotoxic effect and decreased immunity on consumption of of trans fatty acids.

New York City Trans Fat Ban: Improving the Default Option When Purchasing Foods Prepared Outside of the Home

Editorials17 July 2012New York City Trans Fat Ban: Improving the Default Option When Purchasing Foods Prepared Outside of the HomeAlice H. Lichtenstein, DScAlice H. Lichtenstein, DScFrom Tufts University, Boston, MA 02111.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-157-2-201207170-00015 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail The adverse effects of trans fatty acid (trans fat) on cardiovascular health have been known for at least 2 decades (1). During that time, both the Dietary Guidelines for Americans (2) and the Institute of Medicine's Dietary Reference Intake guidelines (3) have recommended restricting trans fat intake to the extent possible. To facilitate adherence to this guidance, the U.S. Food and Drug Administration mandated in 2003 that trans fat content be listed on the Nutrient Facts panel of packaged foods by 2006 (4). This ruling enabled consumers to make purchasing decisions based on the information provided, and it incentivized food ...

Trans Fatty Acids: Chemical Synthesis of Eicosapentaenoic Acid Isomers and Detection in Rats Fed a Deodorized Fish Oil Diet

Eicosapentaenoic acid (EPA) is a polyunsaturated fatty acid present in fish oils used for omega-3 enriched diets. The natural cis double bond geometry can be transformed to the trans configuration during the deodorization process utilized in the food industry. The analytical discrimination of the possible five monotrans regioisomers represents a limiting step for the recognition and structure-activity relationship in connection with the harmful effects of trans fatty acids in health. We carried out a dual synthetic strategy, providing new access to monotrans EPA isomers and valuable information on GC and NMR characteristics for further applications in metabolomics and lipidomics. This small library was used as an analytical reference for isomer determination in deodorized fish oils and the follow-up of rats fed fish oil diets, evidencing for the first time that monotrans EPA isomers are incorporated in liver mitochondrial membranes after dietary intake.

Randomized controlled study of the effect of a butter naturally enriched in trans fatty acids on blood lipids in healthy women

Background: Whereas the negative effect of consuming trans fatty acids found in partially hydrogenated vegetable oils on cardiovascular disease (CVD) risk is well established, the effect of trans fatty acids from ruminant sources (rTFAs) on CVD risk factors has not yet been established, particularly among women.Objective: We investigated the effects of a butter naturally enriched in rTFAs, of which vaccenic acid is the predominant isomer, on plasma lipid concentrations among healthy women.Design: In a double-blind, randomized, crossover controlled study, 61 healthy women aged 19–70 y were fed 2 isoenergetic diets lasting 4 wk each. The 2 diets were defined as moderately high in rTFAs (3.7 g/d, 1.5% of daily energy) and control (0.9 g/d, 0.3% of daily energy).Results: No significant effect of the rTFA diet was found on total plasma cholesterol, LDL cholesterol, apolipoprotein B, apolipoprotein A-I, and triglyceride concentrations compared with the control diet. There was a small yet statistically significant reduction in plasma HDL-cholesterol concentrations with the rTFA diet (−2.8%; P = 0.004), which was significant (P for the BMI × treatment interaction = 0.006) among women with a BMI (in kg/m2) ≥25 (−5.2%; P = 0.004; n = 18) but not among women with a BMI <25 (−1.2%; P = 0.13; n = 43).Conclusions: These results suggest that an increase in dietary rTFAs equivalent to ∼1% of daily energy has no significant effect on LDL but may be associated with a reduction in plasma HDL-cholesterol concentrations, particularly in overweight women. This trial is registered at clinicaltrials.gov as NCT00930137.

In vitro study of dietary factors affecting the biohydrogenation shift from trans-11 to trans-10 fatty acids in the rumen of dairy cows

On the basis of the isomer-specific effects of trans fatty acids (FA) on human health, and the detrimental effect of t10,c12-conjugated linoleic acid (CLA) on cows’ milk fat production, there is a need to identify factors that affect the shift from trans-11 to trans-10 pathway during ruminal biohydrogenation of FA. This experiment was conducted in vitro and aimed at separating the effects of the diet of the donor cows from those of the fermentative substrate, which is necessary to prevent this shift. A total of four dry Holstein dairy cows were used in a 4 × 4 Latin square design. They received 12 kg of dry matter per day of four diets based on maize silage during four successive periods: the control diet (22% starch, <3% fat); the high-starch diet, supplemented with wheat plus barley (35% starch, <3% crude fat); the sunflower oil diet, supplemented with 5% of sunflower oil (20% starch, 7.6% crude fat); and the high-starch plus oil diet (33% starch, 7.3% crude fat). Ruminal fluid of each donor cow was incubated for 5 h with four substrates having similar chemical composition to the diets, replacing sunflower oil by pure linoleic acid (LA). The efficiency of isomerisation of LA to CLA was the highest when rumen fluids from cows receiving dietary oil were incubated with added LA. The shift from trans-11 to trans-10 isomers was induced in vitro by high-starch diets and the addition of LA. Oil supplementation to the diet of the donor cows increased this shift. Conversely, the trans-10 isomer balance was always low when no LA was added to incubation cultures. These results showed that a large accumulation of trans-10 FA was only observed with an adapted microflora, as well as an addition of non-esterified LA to the incubation substrate.

Trans Fatty Acids Enhanced Beta-Amyloid Induced Oxidative Stress in Nerve Growth Factor Differentiated PC12 Cells

The effects of trans fatty acids, elaidic acid (trans-9, C18:1) and linoelaidic acid (trans-9, trans-12 C18:2), at 20 or 40 μM in nerve growth factor differentiated PC12 cells with or without beta-amyloid peptide (Aβ) were examined. Elaidic acid treatment alone did not affect cell viability and oxidative injury associated markers (P > 0.05). However, co-treatments of elaidic acid and Aβ led to more reduction in mitochondrial membrane potential (MMP) and Na⁺-K⁺-ATPase activity, and more increase in DNA fragmentation and 8-hydroxydeoxyguanosine (8-OHdG) production than Aβ treatment alone (P < 0.05). Linoelaidic acid alone exhibited apoptotic and oxidative effects in cells via decreasing MMP and Na⁺-K⁺-ATPase activity, increasing reactive oxygen species (ROS) level, lowering glutathione content and glutathione peroxidase (GPX) activity (P < 0.05). The co-treatments of linoelaidic acid with Aβ further enhanced oxidative damage via enhancing the generation of ROS, nitrite oxide and 8-OHdG, elevating caspase-3, caspase-8 and nitric oxide synthase activities, as well as declining GPX, catalase and superoxide dismutase activities (P < 0.05). These results suggested that the interaction of linoelaidic acid and Aβ promoted oxidative stress and impaired mitochondrial functions in neuronal cells.

Differential effects of various trans fatty acids isomers on apoptosis rate of human umbilical vein endothelial cell in vitro

ObjectiveTo explore the effects of trans fatty acids (TFA) isomers on apoptosis rate of human umbilical vein endothelial cell (HUVECs) in vitro.Methodwe obtained the original generation of HUVECs from umbilical...

Effect of trans fatty acid isomers from ruminant sources on risk factors of cardiovascular disease: Study design and rationale

Substantial evidence clearly demonstrates the deleterious effects of industrially-produced trans fatty acids (TFA); however, data are lacking from large, well controlled human feeding studies that directly compare the effects of industrially-produced and naturally-occurring TFA. The purpose of the current study is to determine whether consumption of TFA derived from different sources differentially affect risk factors of cardiovascular disease (CVD). The study was a randomized, crossover design, controlled-feeding intervention designed to compare the effects of the following diet treatments on risk factors of CVD: low TFA diet (base diet, 34% energy from fat; 0.1% energy from TFA), base diet with vaccenic acid (3.0% energy), base diet with mixed isomers of TFA from partially hydrogenated vegetable oil (3.0% energy), and base diet with cis-9, trans-11 CLA (1.0% energy). The added energy from TFA replaced energy from stearic acid. Participants were required to be between the ages of 25 and 65 years, have a body mass index between 20 and 38 kg/m 2, total cholesterol < 280 mg/dl, fasting triacylglycerol < 300 mg/dl, fasting glucose < 126 mg/dl, and blood pressure < 160/100 mm Hg (controlled with certain medications). Of the 116 participants who were randomized, a total of 95 completed the intervention. Results from this study will be important in determining whether ruminant TFA and industrially produced TFA differentially affect markers of cardiovascular risk, in the context of a highly controlled feeding study.

Lowering LDL-cholesterol through diet: potential role in the statin era

A healthy diet should be rich in vegetables and fruits, whole-grain, high-fiber foods, and fish and should contain a small amount of saturated and trans fats. In addition to these recommendations, some food ingredients such as plant sterol/stanol soy protein and isoflavones may help reduce cholesterol levels. Increased dietary fiber intakes are associated with significantly lower prevalence of cardiovascular disease and lower LDL-cholesterol concentration of about 5-10%. Beyond LDL-cholesterol lowering effects, other benefits have been observed on hypertension, diabetes mellitus. In this review, we summarize the different dietary approaches proven to be associated with LDL-cholesterol decrease. Nutritional interventions that do not exert significant LDL-cholesterol decrease have not been included in this review. On top of a 'classical' step 1 and step 2 diet, the cornerstone of dietary recommendations, recent findings confirm the deleterious effects of trans fatty acid or the beneficial effects of sterols/stanols and nuts. Dietary recommendations may have an impressive impact on cardiovascular events because they can be implemented early in life and because the sum of the effect on LDL-cholesterol is far from being negligible: step 1 diet (-10%), dietary fibers (-5 to -10%), plant sterols/stanols (-10%), nut consumption (-8%), and soy protein (-3 to -10%).

Crystallization of Fully Hydrogenated and Interesterified Fat and Vegetable Oil

Owing to public concern regarding the adverse health effects of trans fatty acids, an alternative technology to trans fats has recently become an important issue. The interesterification of fully hydrogenated vegetable oil and liquid oil blends is one of the most versatile options. This paper reports a physical analysis of high-melting fat (HMF) prepared through the interesterification of fully hydrogenated soybean oil and regular soybean oil, and through fractionation. The thermal and structural properties of the HMF blended with salad oil at a mass ratio of 4:1 (called the HMF blend, hereafter), which was prepared as a model fat blend for margarine, were assessed using X-ray diffraction (XRD), differential scanning calorimetry (DSC), and polarized light microscopy (POM). To observe the polymorphic transformation, all samples were aged after crystallization, and the development of granular crystals during the aging process was observed. We found that the granular crystals are made of SOS/SSO, POS/PSO, and (SOS+POS)/(SSO+PSO) molecular compounds, all of which easily transform into β form with a double-chain-length structure.

Short communication: Effects of trans fatty acids on markers of inflammation in bovine mammary epithelial cells

Trans fatty acids (tFA) contribute to inflammation. The objective was to investigate the effects of tFA on mRNA expression of proinflammatory markers in cultured bovine mammary epithelial cells (MAC-T cell line). Bovine mammary epithelial cells were grown in Dulbecco's Modified Eagle Medium containing 10% fetal bovine serum. Cells were then subcultured in a medium lacking fetal bovine serum, to which incremental concentrations (up to 90μM) of elaidic acid (trans-9 C18:1) or linoleidic acid (trans-9, trans-12 C18:2) were added. Bovine serum albumin (fatty acid-free) solutions were added and cells were collected at specific time points over 48h. Then, RNA was extracted and converted to complementary DNA for quantitative real-time PCR analysis of proinflammatory gene expression. Presence of elaidic acid caused increases in mRNA expression of interleukin (IL)-1β (3.4-fold; dose-independently over a 6-h period) and intercellular adhesion molecule (ICAM)-1 (up to 1.4-fold) relative to that for cells treated with no tFA, whereas expression of IL-6 and IL-8 was reduced 0.75- and 0.85-fold, respectively. Presence of linoleidic acid reduced mRNA expression of IL-6 and IL-8 relative to that for control (0.95- and 0.87-fold, respectively). Trans mono- and dienoic fatty acids upregulated mRNA expression of IL-1β and ICAM-1, whereas expression of IL-6 and IL-8 was downregulated in MAC-T cells. Because these genes are ultimately involved in inflammation, elaidic or linoleidic acid, either directly fed or formed in the rumen during biohydrogenation, may alter the risk for mastitis in vivo.

Trans–fatty acid levels in sperm are associated with sperm concentration among men from an infertility clinic

We measured the sperm fatty acid composition using gas chromatography in anonymized semen samples of 33 men undergoing infertility evaluation at an academic medical center. Trans-fatty acids were present in human sperm and were related inversely to sperm concentration (r = -0.44).

E0001 The effects of trans fatty acids on fatty acid constitution ratios of erythrocyte membrane in rabbits

ObjectiveTo investigate the influences of high trans fatty acids (TFA) intake on fatty-acid constitution ratios of erythrocyte membrane in rabbits.Method32 New Zealand white rabbits were randomly divided into four groups:...

Deposition of trans Fatty Acid from Industrial Sources and Its Effect on Different Growth Phases in Rats

Although the effects of trans fatty acids (TFA) from industrially produced sources (IP-TFA), such as partially hydrogenated vegetable oil, are reported, their implications on metabolism and growth are still not fully disclosed. In this study, female Wistar rats were assigned to control diet (AIN-93G) or Trans diet groups (5% IP-TFA) after gestation. The male offspring were classified and grouped as infant, weanling, and young adult (YA) rats (n = 10), and received the same control or Trans diets throughout their life span. Samples of abdominal adipose tissue, liver and plasma were collected to determine fatty acid profile and fasting glycemia. Morphometric analysis of the liver and hepatosomatic index determination were conducted. Deposition of TFA was observed in the liver, adipose tissue and plasma of IP-TFA-fed rats. Fasting glycemia concentration was higher in Trans YA rats than in the control YA group (p = 0.004). A higher accumulation of fat was observed in the liver of the Trans group than in the control group during the three phases. Hepatosomatic index was higher in the YA Trans group than in the YA control group (p < 0.05). Dietary TFA was deposited in the tissues and plasma and raised fasting glucose in growing rats.

Explaining the 25-year decline of serum cholesterol by dietary changes and use of lipid-lowering medication in Finland

To assess to what extent the observed dietary changes and increased use of lipid-lowering medication can explain the almost 20 % decline in serum cholesterol (referring to serum total cholesterol) level observed from 1982 to 2007 in Finland. Predicted changes of serum cholesterol were calculated by the Keys' equation assuming the effect of trans fatty acids to be similar to SFA and using the dietary intake data of the national dietary surveys between 1982 and 2007. The effect of medication was estimated based on the information on use of lipid-lowering medication among survey participants. The predicted serum cholesterol levels were compared with observed changes in analysed serum cholesterol levels. Four cross-sectional population surveys, in 1982, 1992, 2002 and 2007, in the provinces of North Karelia, Northern Savo and Southwestern Finland. A total of 2325 men and 2638 women aged 26-64 years selected randomly from the national population register for the four surveys. Changes in dietary fat quality and cholesterol intake explain 0.70 mmol/l (65 %) of the decrease in men and 0.65 mmol/l (60 %) of the decrease in women in all subjects. Decline in dietary SFA intake is the main explanatory factor (47 % in men and 41 % in women) for the changes. The impact of lipid-lowering medication on observed cholesterol levels was found to be 16 % among men and 7 % among women. The decrease in serum cholesterol levels in Finland can be explained mainly by dietary changes, especially changes in fat quality. The effect of lipid-lowering medication is less significant.

Effects of trans fatty acid (tFA)‐free fat formulations on lipid and lipoprotein metabolism in gerbils and hamsters

The adverse health effects of dietary tFA resulting from the partial hydrogenation of liquid vegetable oils (PHVO) have prompted health agencies to advocate their reduction or complete elimination from the food supply. Alternatives to PHVO are being considered, including genetically modified oils with reduced PUFA, interesterified fats high in stearic acid, and naturally occurring oil blends with increased SFA. In the current study, we evaluated various oil blends‐ soybean oil (SO), low‐linoleic SO, interesterified SO, coconut oil, a vegetable‐oil blend (palm, corn &amp; sunflower) and a palm oil fraction with an increased content of oleic acid for their effects on lipid and lipoprotein metabolism. In all, 96 male Mongolian gerbils and 75 male Golden Syrian hamsters were fed purified diets for 4 weeks containing ~ 30% calories from the test fat blends and ~0.1% w/w cholesterol. Plasma lipids, lipoprotein concentrations, composition, and particle sizes, and liver free and esterified cholesterol were measured. Despite minor differences between individual diets, only the coconut oil‐based diet (99% coconut oil, 1% SO) induced hypercholesterolemia in both species. These data suggest that within the context of currently recommended prudent diets, various tFA‐free fat formulations can be utilized without compromising plasma lipids. Whether the same occurs in humans is under investigation.

Effect of Animal and Industrial Trans Fatty Acids on HDL and LDL Cholesterol Levels in Humans – A Quantitative Review

Background Trans fatty acids are produced either by industrial hydrogenation or by biohydrogenation in the rumens of cows and sheep. Industrial trans fatty acids lower HDL cholesterol, raise LDL cholesterol, and increase the risk of coronary heart disease. The effects of conjugated linoleic acid and trans fatty acids from ruminant animals are less clear. We reviewed the literature, estimated the effects trans fatty acids from ruminant sources and of conjugated trans linoleic acid (CLA) on blood lipoproteins, and compared these with industrial trans fatty acids.Methodology/Principal FindingsWe searched Medline and scanned reference lists for intervention trials that reported effects of industrial trans fatty acids, ruminant trans fatty acids or conjugated linoleic acid on LDL and HDL cholesterol in humans. The 39 studies that met our criteria provided results of 29 treatments with industrial trans fatty acids, 6 with ruminant trans fatty acids and 17 with CLA. Control treatments differed between studies; to enable comparison between studies we recalculated for each study what the effect of trans fatty acids on lipoprotein would be if they isocalorically replaced cis mono unsaturated fatty acids. In linear regression analysis the plasma LDL to HDL cholesterol ratio increased by 0.055 (95%CI 0.044–0.066) for each % of dietary energy from industrial trans fatty acids replacing cis monounsaturated fatty acids The increase in the LDL to HDL ratio for each % of energy was 0.038 (95%CI 0.012–0.065) for ruminant trans fatty acids, and 0.043 (95% CI 0.012–0.074) for conjugated linoleic acid (p = 0.99 for difference between CLA and industrial trans fatty acids; p = 0.37 for ruminant versus industrial trans fatty acids).Conclusions/SignificancePublished data suggest that all fatty acids with a double bond in the trans configuration raise the ratio of plasma LDL to HDL cholesterol.

Effects of different levels of trans fatty acids and oxidised lipids in diet on cholesterol and cholesterol oxidation products formation in rabbit

The objective was to assess the effects of trans fatty acids and oxidised lipids, present in dietary fat by-products used in feeds, on cholesterol and oxycholesterols in meat, liver and plasma of rabbits. A palm fatty acid distillate, before and after hydrogenation ( trans fatty acid trial), and a sunflower–olive oil blend (70/30, v/v), before and after use in a commercial frying process (oxidised lipid trial), were used in experimental feeds (at 3%, w/w). High trans fatty acid and oxidised lipid diets caused significantly higher cholesterol and oxycholesterol levels in all tissues of rabbit (0.01 < p ⩽ 0.05). The content of oxycholesterols in rabbit meat, liver and plasma obtained from trans fatty acid experiments varied from 9 to 34 μg/100 g, 24 to 61 μg/100 g and 60 to 138 μg/dl, respectively, from low to high levels. In the oxidised lipid experiments, content of oxycholesterols varied from 16 to 52 μg/100 g, 14 to 108 μg/100 g and 52 to 269 μg/dl in meat, liver and plasma, respectively. As a consequence, meat products from rabbits fed a diet containing higher levels of trans fatty acids or oxidised lipids may result in higher intakes of cholesterol and oxycholesterols by humans.

Effect of a High Intake of Conjugated Linoleic Acid on Lipoprotein Levels in Healthy Human Subjects

BackgroundTrans fatty acids are produced either by industrial hydrogenation or by biohydrogenation in the rumens of cows and sheep. Industrial trans fatty acids lower high-density lipoprotein (HDL) cholesterol, raise low-density lipoprotein (LDL) cholesterol, and increase the risk of coronary heart disease. The effects of trans fatty acids from ruminants are less clear. We investigated the effect on blood lipids of cis-9, trans-11 conjugated linoleic acid (CLA), a trans fatty acid largely restricted to ruminant fats.Methodology/Principal FindingsSixty-one healthy women and men were sequentially fed each of three diets for three weeks, in random order, for a total of nine weeks. Diets were identical except for 7% of energy (approximately 20 g/day), which was provided either by oleic acid, by industrial trans fatty acids, or by a mixture of 80% cis-9, trans-11 and 20% trans-10, cis-12 CLA. After the oleic acid diet, mean (± SD) serum LDL cholesterol was 2.68±0.62 mmol/L compared to 3.00±0.66 mmol/L after industrial trans fatty acids (p<0.001), and 2.92±0.70 mmol/L after CLA (p<0.001). Compared to oleic acid, HDL-cholesterol was 0.05±0.12 mmol/L lower after industrial trans fatty acids (p = 0.001) and 0.06±0.10 mmol/L lower after CLA (p<0.001). The total-to–HDL cholesterol ratio was 11.6% higher after industrial trans fatty acids (p<0.001) and 10.0% higher after CLA (p<0.001) relative to the oleic acid diet.Conclusions/SignificanceHigh intakes of an 80∶20 mixture of cis-9, trans-11 and trans-10, cis-12 CLA raise the total to HDL cholesterol ratio in healthy volunteers. The effect of CLA may be somewhat less than that of industrial trans fatty acids.Trial RegistrationClinicalTrials.gov NCT00529828