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Association of trans fatty acids (vegetable ghee) and clarified butter (Indian ghee) intake with higher risk of coronary artery disease in rural and urban populations with low fat consumption.

These cross-sectional surveys included 1769 rural (894 men and 875 women) and 1806 urban (904 men and 902 women) randomly selected subjects between 25-64 years of age from Moradabad in North India. The total prevalence of coronary artery disease based on clinical history and electrocardiogram was significantly higher in urban compared to rural men (11.0 vs. 3.9%) and women (6.9 vs. 2.6%), respectively. Food consumption patterns showed that important differences in relation to coronary artery disease were higher intake of total visible fat, milk and milk products, meat, eggs, sugar and jaggery in urban compared to rural subjects. Prevalence of coronary artery disease in relation to visible fat intake showed a higher prevalence rate with higher visible fat intake in both sexes and the trend was significant for total prevalence rates both for rural and urban men and women. Subgroup analysis among urban (694 men and 694 women) and rural (442 men and 435 women) subjects consuming moderate to high fat diets showed that subjects eating trans fatty acids plus clarified butter or those consuming clarified butter as total visible fat had a significantly higher prevalence of coronary artery disease compared to those consuming clarified butter plus vegetable oils in both rural (9.8, 7.1 vs. 3.0%) and urban (16.2, 13.5 vs. 11.0%) men as well as in rural (9.2, 4.5 vs. 1.5%) and urban (10.7, 8.8 vs. 6.4%) women. Univariate and multivariate regression analysis with adjustment for age showed that sedentariness in women, body mass index in urban men and women, milk and clarified butter plus trans fatty acids in both rural and urban in both sexes were significantly associated with coronary artery disease. It is possible that lower intake of total visible fat (20 g/day), decreased intake of milk, increased physical activity and cessation of smoking may benefit some populations in the prevention of coronary artery disease.

Adult↗

Trans fatty acids in margarines and shortenings marketed in Austria.

Margarines and shortenings available in Austria were repeatedly sampled in 1991/1992 and the content of trans fatty acids (TFA) determined by using capillary GLC. Wide variations of the TFA contents with respect to intra- and inter-brand differences were observed. Diet margarines contained up to 1% TFA, while TFA concentrations in tub or stick margarines were much higher (15.7 +/- 5.8% and 21.3 +/- 5.3%, respectively). A sub-set of samples was also purchased in 1995 and a general reduction of the TFA content was noticed. Taking into account different market shares of certain margarine types, a weighted average of 15.7% TFA and 6.5% TFA was calculated for the 1991/1992 and the 1995 samples. Based on availability data the amount of TFA supplied with margarines was estimated to be 3.7 g per person per day, while a more accurate method of measuring dietary intakes, i.e. diet history and food frequency data, approximates the amount of TFA supplied with margarines to be 1.5 g per person per day for the 1991/1992 samples and 0.6 g for the 1995 samples.

Austria↗

Intake of trans fatty acids and low-density lipoprotein size in a Costa Rican population.

Intervention studies show that dietary composition altered low-density lipoprotein (LDL) particle size, but population studies are scarce, and the potential effects of trans fatty acids (FA) on LDL size are unknown. Trans FA intake has been associated with a more atherogenic lipid profile and increased coronary heart disease (CHD). We examined the association between dietary intake, including trans FA and LDL size, in 414 randomly selected subjects living in Puriscal, Costa Rica. Dietary intake was assessed by a validated food frequency questionnaire (FFQ). Women had larger LDL size (A) compared with men (263 v 261), and large LDL particles were correlated with increased intake (% energy) of protein (P =.005), animal fat (P =.041), trans FA (P <.0001), and decreased intake of carbohydrate (P =.052) in sex-, age-, and total energy intake-adjusted models. The correlation between trans FA intake and large LDL was significant in multivariate models that included dietary and nondietary factors; a 1% difference in trans FA was associated with a 2.44 A increase in LDL size (P =.004). In sum, it is possible that the effects of dietary factors, such as intake of trans FA on CHD are mediated through their effects on LDL size.

Adult↗

Determination of trans fatty acids in cold pressed oils.

The adulteration of cold pressed oils (CPO) by refining or by blending with refined oils will lead to an increase of trans fatty acids (TFA) in such oils. The regulations of the European Community (EC) demand strict processing conditions without any steam treatment for cold pressed, native olive oils and provide limits for TFA. German regulations, however, allow a "steam washing" for CPO other than native olive oil and offer no limits for TFA. The TFA content of such oils could exceed the limits for cold pressed, native olive oil. Modern capillary GLC serves as a quick tool for the detection of TFA formed during deodorization and other processing. However, care should be taken to avoid the formation of TFA during analysis. We evaluated the content of TFA in several oils labelled as cold pressed and the formation of TFA during "steam washing". Analysis of some seeds indicates that preliminary drying of the seeds may also lead to TFA.

Chromatography, Gas↗

Hydrogenation impairs the hypolipidemic effect of corn oil in humans. Hydrogenation, trans fatty acids, and plasma lipids.

The effects of plasma lipoproteins and apolipoproteins of replacing corn oil with corn-oil margarine in stick form as two thirds of the fat in the National Cholesterol Education Program (NCEP) Step 2 diet were assessed in 14 middle-aged and elderly women and men (age range, 44-78 years) with moderate hypercholesterolemia (low density lipoprotein cholesterol [LDL-C] range, 133-219 mg/dl [3.45-5.67 mmol/l] at screening). During each 32-day study phase, subjects received all their food and drink from a metabolic kitchen. Subjects were first studied while being fed a diet approximating the composition of the current US diet (baseline), which contained 35% of calories as fat (13% saturated fatty acids [SFAs], 12% monounsaturated fatty acids [MUFAs; 0.8% 18:1n-9 trans], and 8% polyunsaturated fatty acids [PUFAs]) and 128 mg cholesterol/1,000 kcal. This baseline phase was followed by a corn oil-enriched diet containing 30% fat (6% SFA, 11% MUFA [0.4% 18:1n-9 trans], and 10% PUFA) and 83 mg cholesterol/1,000 kcal, and then a corn-oil margarine-enriched diet containing 30% fat (8% SFA, 12% MUFA [4.2% 18:1n-9 trans], and 8% PUFA) and 77 mg cholesterol/1,000 kcal. All diets were isocaloric. Mean fasting LDL-C and apolipoprotein (apo) B levels were 153 mg/dl (3.96 mmol/l) and 101 mg/dl on the baseline diet, 17% and 20% lower (both p < 0.001) on the corn oil-enriched diet, and 10% and 10% lower (both p < 0.01) on the margarine-enriched diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Effect of variation of trans-fatty acid in lactating rats' diet on lipoprotein lipase activity in mammary gland, liver, and adipose tissue.

OBJECTIVE: Lactation is associated with an increase in lipoprotein lipase (LPL) activity in the mammary gland (MG) and a decrease in adipose tissue because lactation redirects circulating substrates to the MG for milk synthesis. We investigated the effects of different dietary contents of trans-fatty acid (TFA) on LPL activity in maternal tissues and fatty acid composition in milk. METHODS: Lactating rats were fed semisynthetic isocaloric diets containing 7% soy oil (control), 7% partially hydrogenated vegetable oil (7%-PHVO), 5% PHVO plus 2% soy oil (5%-PHVO), or 3.5% PHVO plus 3.5% soy oil (3.5%-PHVO). On lactation day 14, animals were decapitated and MG, liver, and parametrial adipose tissue were extracted to determine total lipid contents, percentages of TFA, and LPL activity. Milk lipid composition was examined by gas chromatographic analysis of the gastric content of 14-d-old suckling pups. RESULTS: Maternal consumption of TFA increased dietary TFA incorporation in MG and liver and decreased it in parametrial adipose tissue. Diets with higher trans concentrations (7%-PHVO) significantly increased lipid content in the MG, and all groups fed trans-based diets showed significant increases in LPL activity in the MG. Although LPL increased in the MG, milk of rats fed TFA-based diets had significant decreases in the percentage of essential fatty acids. CONCLUSIONS: TFA intake during lactation alters maternal lipid metabolism and the percentage of essential fatty acids in milk; therefore, it is important to alert the population to avoid excessive intake of TFAs during lactation.

Adipose Tissue↗

Blood omega-3 and trans fatty acids in middle-aged acute coronary syndrome patients.

We tested the hypothesis that lower blood omega-3 (omega-3) fatty acids (FAs) and/or higher trans FAs are associated with the risk of an acute coronary syndrome (ACS). Higher levels of omega-3 FA have been associated with decreased risk of sudden cardiac death. However, their association with ACS risk is unclear. Although higher self-reported intakes of trans FAs have been linked to increased coronary risk, the association between blood levels of trans FA and ACS risk is also unknown. We analyzed the FA composition of whole blood from 94 subjects with ACS and 94 age-, gender-, and race-matched controls. Omega-3 and trans FA associations with ACS were assessed using multivariable models after adjusting for smoking status, alcohol use, diabetes, body mass index, serum lipids, and history of myocardial infarction or revascularization. Subjects' mean age was 47 years, 54% were men, and 80% were Caucasian. Whole blood long-chain omega-3 FA (eicosapentaenoic acid [EPA] plus docosahexaenoic acid [DHA]) content was 29% lower in patients than in controls (1.7 +/- 0.9% vs 2.4 +/- 1.4%, p <0.001), whereas trans FA content was not different (2.1 +/- 0.7% vs 2.0 +/- 0.9%, p = NS). The multivariable-adjusted odds for case status was 0.67 (95% confidence interval 0.46 to 0.98) for a 1 SD increase in blood EPA + DHA. The inclusion of trans FAs in the EPA + DHA model did not alter this association. In conclusion, low blood EPA + DHA content is an independent predictor of increased risk for ACS, but higher blood trans FA content is not. Blood EPA + DHA may serve as a new, modifiable risk factor for ACS.

Acute Disease↗

Effect of dietary trans fatty acids on some membrane-associated enzymes and receptors in rat heart.

Three groups of male weanling Sprague-Dawley rats were fed diets containing 20% corn oil, 20% partially hydrogenated soybean oil (PHSBO) or 18% PHSBO + 2% corn oil. PHSBO contained about 48% of its total fatty acids as trans-octadecenoate. Rats were killed after 16-18 weeks of feeding the various diets, hearts were dissected and crude sarcolemma was prepared by differential centrifugation. The activities of ouabain-sensitive (Na+ + K+)ATPase were significantly lower in membranes of rats fed 20% PHSBO than the control rats fed 20% corn oil. The feeding of 2% corn oil with 18% PHSBO resulted in partial restoration of the enzyme activity. The maximum number of [3H]ouabain-binding sites (Bmax) was also lower in cardiac membranes of rats fed 20% PHSBO than those fed 20% corn oil. Similar to (Na+ + K+)-ATPase activity, some restoration of the number of [3H]ouabain-binding sites was observed when 2% corn oil was fed with 18% PHSBO-containing diet. There was no difference in the binding affinity of the radioligand for the receptor among the 3 dietary groups. Adenylate cyclase activities (fluoride-, isoproterenol- and forskolin-stimulated) were lower in membranes of rats fed 20% PHSBO or 18% PHSBO + 2% corn oil than in the control group fed 20% corn oil. Density of the beta-adrenergic receptor was the lowest in cardiac membranes of rats fed 20% PHSBO. The feeding of 2% corn oil with 18% PHSBO resulted in partial restoration of the maximum number of [3H]dihydroalprenolol (DHA)-binding sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗

Contribution of trans fatty acids from vegetable oils and margarines to the Belgian diet.

Nineteen commercial samples of vegetable oils and margarines marketed in Belgium (nine margarines, nineteen vegetable oils), Hungary (seven margarines) and Great Britain (three margarines) were analyzed by gas-liquid chromatography for their trans fatty acid (TFA) content. For the vegetable oil samples under study, the TFA content ranged from 0.0-4.6% (mean : 1.1%, S.D. : 1.1%). Trans isomers in these samples were almost exclusively C18:2 and C18:3 isomers formed during high temperature refining. Trans isomers of the margarines were mainly C18:1 isomers formed during hydrogenation. For the Belgian and Hungarian samples mean trans values of 6.36% (S.D.=6.20%) and 14.06% (S.D.=7.59%), respectively expressed on fat basis were established. From these figures, the average daily intake of TFA from margarines and vegetable oils by the Belgian population was calculated at 1.1 and 0.1g/person/day, respectively. When so-called zero-trans margarines (+/- 0.5% TFA) are consumed, the trans intake can be reduced to about 0.1g/person/day. Further studies leading to figures about the contribution of TFA from 'invisible fat' food products will be conducted in the near future.

Belgium↗

Influence of dietary trans-fatty acids on swine lipoprotein composition and structure.

Four groups of 20 weanling swine each were fed either (a) basal diet, (b) basal plus hydrogenated fat (13% trans), (c) basal plus hydrogenated fat (13% trans) and 0.4% cholesterol, or (d) basal plus beef tallow (all cis). After six months of feeding, the animals were killed and the blood and aortas were removed. Very low density, low density, and high density lipoproteins were then isolated from the plasma by ultracentrifugal flotation. Although the fatty acid composition of the basal diet was different from the diets supplemented with either hydrogenated fat containing trans-fatty acid or beef tallow containing all cis, the lipid and fatty acid compositions of each of the isolated lipoprotein classes for the four groups of animals were remarkably similar. Elaidate was clearly incorporated into the lipoproteins of animals fed hydrogenated fat, but the level of incorporation was generally less than 5%. In a direct comparison of the structure of the lipoproteins from the different groups, we did not find any significant differences in their physical properties as determined by pyrene fluorescence and electron paramagnetic resonance methods. Grossly visible fatty streaks and fibrous plaques were not found in any of the swine aorta. However, light and electron microscopy indicated the presence of atherosclerotic lesions in the distal abdominal aorta and bifurcation. These studies demonstrate that a diet containing a substantial amount of trans-fatty acid leads to a small but definite incorporation into the swine lipoproteins. However, such changes had relatively little effect on lipoprotein structure or the presence of atherosclerotic lesions in these 6-month-old swine.

Animals↗

Trans fatty acids: positional specificity in brain lecithin.

Fifteen-day-old rats were divided into three groups: one group received an intracerebral injection of 5 microCi of 9-trans,12-trans [1-(14)C] octadecadienoic acid; the second group was given 5 microCi of the same compound plus an equal wt of nonradioactive all cis arachidonic acid; the third group was given 5 microCi of 9-trans [1-(14)C] octadecenoic acid. All animals were sacrificed 8 hr after injection. Glycerophosphocholine (GPC) was isolated and partically deacylated with phospholipase A2 from Crotalus Adamanteus venom. The results of this study were as follows: 1) after t[1-(14)C]18:1 injection, there was twice as much radioactivity in the 1-position as in the 2-position; 2) when tt[1-(14)C] 18:2 was injected, more than 90% of the total radioactivity was found in the 2-position; 3) following tt[1-(14)C]-18:2 + nonradioactive arachidonate injection, ca. 75% of the total radioactivity still remained in the 2-position; and 4) all of the injected [1-(14)C]-tracers showed evidence of undergoing beta-oxidation to form acetyl-CoA, which was converted to radioactive palmitate. The possibility is discussed that the observed distribution pattern of the injected radioactive tracers may be attributed to tissue metabolic specificity. Ramifications of the deposition of dietary trans fatty acids in the brain during the developmental stage of the central nervous system are also discussed.

Animals↗

Dietary trans fatty acids modulate erythrocyte membrane fatty acyl composition and insulin binding in monkeys.

The substitution of trans- for half of the cis-monounsaturated fatty acids in the diet of Macaca fasicularis monkeys resulted in alterations in erythrocyte fatty acid composition and insulin receptor properties but not in membrane fluidity. Both cis and trans diets contained 10% fat and similar fatty acid compositions, except that approximately 50% of the cis-octadecenoate (c-18:1) in the cis diet was replaced with trans-octadecenoate isomers (t-18:1) in the trans diet. Compared with the cis diet, the trans diet resulted in the incorporation of approximately 11% t-18:1, an approximately 50% decrease in c-18:1, an approximately 16% decrease in total saturated fatty acids, and an approximately 20% increase in 18:2(n-6) in erythrocyte membrane lipids. The increase in 18:2(n-6) may reflect on homeostatic mechanisms designed to maintain overall membrane fluidity, as no diet-related changes in fluidity were observed with diphenylhexatriene steady state fluorescence polarization. Values observed for insulin binding and insulin receptor number were higher and binding affinity was lower in monkeys fed the cis diet. In the absence of an effect on overall membrane fluidity, altered receptor activity suggests that insulin receptor activity is dynamic, requiring specific fluid membrane subdomains or highly specific fatty acid-protein interactions.

Journal Article↗

Modulation of opioid receptor binding by cis and trans fatty acids.

In synaptosomal brain membranes, the addition of oleic acid (cis), elaidic acid (trans), and the cis and trans isomers of vaccenic acid, at a concentration of 0.87 mumol of lipid/mg of protein, strongly reduced the Bmax and, to a lesser degree, the binding affinity of the mu-selective opioid [3H]Tyr-D-Ala-Gly-(Me)Phe-Gly-ol ([3H]DAMGO). At comparable membrane content, the cis isomers of the fatty acids were more potent than their trans counterparts in inhibiting ligand binding and in decreasing membrane microviscosity, both at the membrane surface and in the core. However, trans-vacenic acid affected opioid receptor binding in spite of just marginally altering membrane microviscosity. If the receptors were uncoupled from guanine nucleotide regulatory protein, an altered inhibition profile was obtained: the impairment of KD by the fatty acids was enhanced and that of Bmax reduced. Receptor interaction of the delta-opioid [3H](D-Pen2,D-Pen5)enkephalin was modulated by lipids to a greater extent than that of [3H]DAMGO: saturable binding was abolished by both oleic and elaidic acids. The binding of [3H]naltrexone was less susceptible to inhibition by the fatty acids, particularly in the presence of sodium. In the absence of this cation, however, cis-vaccenic acid abolished the low-affinity binding component of [3H]naltrexone. These findings support the membrane model of opioid receptor sequestration depicting different ionic environments for the mu- and delta-binding sites. The results of this work show distinct modulation of different types and molecular states of opioid receptor by fatty acids through mechanisms involving membrane fluidity and specific interactions with membrane constituents.

Animals↗