Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Trans Fatty Acids”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed2006

Effects of dairy products naturally enriched with cis-9,trans-11 conjugated linoleic acid on the blood lipid profile in healthy middle-aged men.

BACKGROUND: Interest in the development of dairy products naturally enriched in conjugated linoleic acid (CLA) exists. However, feeding regimens that enhance the CLA content of milk also increase concentrations of trans-18:1 fatty acids. The implications for human health are not yet known. OBJECTIVE: This study investigated the effects of consuming dairy products naturally enriched in cis-9,trans-11 CLA (and trans-11 18:1) on the blood lipid profile, the atherogenicity of LDL, and markers of inflammation and insulin resistance in healthy middle-aged men. DESIGN: Healthy middle-aged men (n = 32) consumed ultra-heat-treated milk, butter, and cheese that provided 0.151 g/d (control) or 1.421 g/d (modified) cis-9,trans-11 CLA for 6 wk. This was followed by a 7-wk washout and a crossover to the other treatment. RESULTS: Consumption of dairy products enriched with cis-9,trans-11 CLA and trans-11 18:1 did not significantly affect body weight, inflammatory markers, insulin, glucose, triacylglycerols, or total, LDL, and HDL cholesterol but resulted in a small increase in the ratio of LDL to HDL cholesterol. The modified dairy products changed LDL fatty acid composition but had no significant effect on LDL particle size or the susceptibility of LDL to oxidation. Overall, increased consumption of full-fat dairy products and naturally derived trans fatty acids did not cause significant changes in cardiovascular disease risk variables, as may be expected on the basis of current health recommendations. CONCLUSION: Dairy products naturally enriched with cis-9,trans-11 CLA and trans-11 18:1 do not appear to have a significant effect on the blood lipid profile.

Adult↗
PubMed1983

Suppression of arachidonic acid in lipids of rat tissues by dietary mixed isomeric cis and trans octadecenoates.

The influence of dietary isomeric cis and trans octadecenoic fatty acids (ICTO) on the metabolism of polyunsaturated fatty acids in rat tissues was studied by feeding a defined diet rich in partially hydrogenated soybean oil. Experimental and control animals received equal and more than adequate amounts of linoleic and linolenic acids. The total phospholipid (PL) fatty acids of liver, heart, testis, brain and sciatic nerve, and the fatty acids of liver triacylglyceride, cholesteryl ester and individual PL classes were analyzed by capillary gas chromatography. The content of arachidonic acid in the total fatty acids of liver lipids of ICTO-fed rats was found to be lower than those from control rats by the following amounts (in percent): total PL, 35; phosphatidylcholine, 50; phosphatidylinositol, 35; phosphatidylserine 26; phosphatidylethanolamine, 12; cholesteryl ester, 55; and tryglyceride 75. PL 18:2 omega 6 and 20:3 omega 6 levels were elevated, suggesting inhibition of the desaturase-elongase enzymes involved in synthesis of arachidonic acid. Synthesis of 20:5 omega 3 and 20:3 omega 9 was accentuated by the ICTO diet, suggesting an omega 6 series-specific inhibition. A nearly perfect negative correlation between cis 12-18:1 and arachidonic acid was found in liver PL.

Animals↗
PubMed2007

Dietary fatty acid intakes and the risk of ovulatory infertility.

BACKGROUND: Pharmacologic activation of the peroxisome proliferator-activated receptor gamma (PPAR-gamma) improves ovulatory function in women with polycystic ovary syndrome, and specific dietary fatty acids can affect PPAR-gamma activity. OBJECTIVE: The objective of the study was to assess whether the intakes of total fat, cholesterol, and major types of fatty acids affect the risk of ovulatory infertility. DESIGN: We conducted a prospective cohort study of 18 555 married, premenopausal women without a history of infertility who attempted a pregnancy or became pregnant between 1991 and 1999. Diet was assessed twice during follow-up by using a food-frequency questionnaire. RESULTS: During follow-up, 438 incidents of ovulatory infertility were reported. In logistic regression analyses, intakes of total fat, cholesterol, and most types of fatty acids were not related to ovulatory infertility. Each 2% increase in the intake of energy from trans unsaturated fats, as opposed to that from carbohydrates, was associated with a 73% greater risk of ovulatory infertility after adjustment for known and suspected risk factors for this condition [relative risk (RR) = 1.73; 95% CI: 1.09, 2.73]. Obtaining 2% of energy intake from trans fats rather than from n-6 polyunsaturated fats was associated with a similar increase in the risk of ovulatory infertility (RR = 1.79; 95% CI: 1.11, 2.89). In addition, obtaining 2% of energy from trans fats rather than from monounsaturated fats was associated with a more than doubled risk of ovulatory infertility (RR = 2.31; 95% CI: 1.09, 4.87). CONCLUSION: trans Unsaturated fats may increase the risk of ovulatory infertility when consumed instead of carbohydrates or unsaturated fats commonly found in nonhydrogenated vegetable oils.

Adult↗
PubMed1985

Effect of very long chain fatty acids on peroxisomal beta-oxidation in primary rat hepatocyte cultures.

Previous studies have demonstrated that certain high fat diets can induce peroxisomal fatty acid beta-oxidation in rodent liver and that this may be due to their content of trans 22:1 fatty acids. In this study we have examined the effects of cis and trans 22:1 fatty acids (erucic and brassidic) and oleic acid (18:1) on palmitoyl-CoA oxidation, carnitine acetyltransferase and carnitine palmitoyltransferase activities in primary rat hepatocyte cultures. Brassidic and erucic acid and, to a lesser extent, oleic acid were cytotoxic to rat hepatocytes. However, at a concentration of 0.1 mM, brassidic acid produced small increases in palmitoyl-CoA oxidation and carnitine acetyltransferase activities in hepatocytes cultured 70 hr. Treatment of cells with 0.1 and 0.3 mM of either erucic or oleic acid had no effect on any of the enzymes measured.

Animals↗
PubMed1994

Cis/trans isomerization of fatty acids as a defence mechanism of Pseudomonas putida strains to toxic concentrations of toluene.

Defence mechanisms of three Pseudomonas putida strains growing in the presence of toluene up to 50% (v/v) were investigated. The three strains reacted to toxic concentrations of toluene by accumulating trans unsaturated fatty acids in the membrane instead of the cis isomers. The membranes of the toluene-adapted cells possessed a higher trans/cis ratio and had a higher lipid-ordering since the transition temperature was about 7 centigrade degrees higher compared to the non-adapted cells.

Drug Resistance, Microbial↗
PubMed1982

Positional distribution of fatty acids in the triglyceride classes of milk fat.

A sample of milk fat was fractionated into high, medium and low molecular weight triglycerides by silicic acid column chromatography. Each fraction was further separated by silver ion adsorption thin-layer chromatography into triglyceride class which were subjected to stereospecific analysis. Trans-monoene fatty acids were incorporated into triglycerides in the same manner as their cis-isomer. The specific positional distribution for fatty acids in intact mild fat triglycerides was not always maintained in the molecular weight fractions or in the various classes of unsaturation. The significance of these findings is discussed in relation to biosynthetic mechanisms for milk fat synthesis.

Animals↗
PubMedDate not supplied

Comparison of phosphatidylcholine vesicle properties related to geometrical isomerism.

Glycerophosphatidylcholine containing trans-unsaturated fatty acid residues was prepared by reaction of the corresponding naturally occurring cis lipid with photochemically generated thiyl radicals. This modified lipid was chosen as the simplest model for gaining some insights of the complex scenario of membrane formation, in connection with the role of lipid geometry and the predominance of cis lipids in eukaryotic cells. The critical aggregation concentration for the spontaneous formation of vesicles was determined for cis and trans isomers with cis-parinaric acid used as a fluorescent probe and it was found to be similar for both lipids. Vesicle dimensions were investigated by light scattering and electron microscopy, and the type of fatty acid residues influenced the vesicle diameter, with a decrease along the series cis > trans > saturated. Fluorescence measurement of dye release from trans and cis vesicles showed also a different permeability. A picture emerged of the geometrical isomer preference in cells as a process driven by natural selection during the life evolution of different organisms, both in terms of compartment dimensions and membrane functionality.

Isomerism↗
PubMed1991

Fatty acid composition of mature human milk in Nigeria.

The fatty acid composition of mature human milk from 10 rural Nigerian women was analyzed by high-resolution capillary gas-liquid chromatography and compared to previously determined results on mature human milk from 15 German mothers. Human milk of the Nigerian group contains significantly higher proportions of saturated fatty acids (median 54.07 vs. 42.76% wt/wt). The difference is primarily caused by high values for lauric (C12:0, 8.34%) and myristic acids (C14:0, 9.57%), but not of medium chain fatty acids (C8:0, C10:0), presumably due to increased de novo fatty acid synthesis in the African women consuming a high carbohydrate and low-fat diet. Markedly lower values of oleic and total cis-monounsaturated (22.82 vs. 37.98%) as well as trans-isomeric fatty acids (1.20 vs. 4.40%) in Nigerian milk appear to result from low dietary intakes of animal and partially hydrogenated fats, respectively. Although percentage contribution of linoleic acid (18:2n-6) is similar, arachidonic acid (C20:4n-6) and total n-6 long-chain polyunsaturates with 20 and 22 carbons (n-6 LCP) are higher in the African samples. N-6 LCP secretion with human milk lipids is not correlated to the precursor linoleic acid and seems not to depend on maternal dietary intake of preformed dietary LCP with animal fats. N-3 LCP are very high in milk of the Nigerian women who obtain a large portion of dietary lipids from sea fish, but even then docosaehexanoic (C22:6n-3) and not eicosapentaenoic (C20: 5n-3) is the predominant n-3 LCP in milk.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Feeding↗
PubMedDate not supplied

Conjugated linoleic acid isomers and their conjugated derivatives inhibit growth of human cancer cell lines.

Conjugated linoleic acid (CLA), mainly c9,t11- and t10,c12-isomers, and polyunsaturated n-3 fatty acids (n-3 PUFA) have been shown to reduce tumor growth. This study compared, on a set of human tumor cells (breast, lung, colon, prostate and melanoma), the antiproliferative effects of: i) trans monounsaturated fatty acids (MUFA) vs. cis MUFA and MUFA vs. PUFA, ii) individual isomers of CLA vs. linoleic acid, iii) CLA-conjugated derivatives vs. their non-conjugated homologues and vs. CLA isomers. Tumor cells were exposed to medium containing individual FA (100 microM) for 48 h and their proliferation was determined by measuring the cellular DNA content (fluorescent Hoechst 33342 dye). The antiproliferative effects of FA varied with the type of cells and were mainly dependent on the degree of unsaturation and on the position and configuration of their double bonds. One isomer of CLA (t9,t11-18:2) and CLA-conjugated derivatives exhibited the strongest growth-inhibitory effect against cancer cells. These results suggest that ruminant products contain active compounds against human tumor cell proliferation.

Cell Growth Processes↗
PubMed2003

A Mucor rouxii mutant with high accumulation of an unusual trans-linoleic acid (9c,12t-C18:2).

Genetic and biochemical approaches reveal the existence of a gamma-linolenic acid biosynthetic pathway in Mucor rouxii. By treatment with ultraviolet light, combined with low temperature cultivation and filtration enrichment, a mutant defective in polyunsaturated fatty acid synthesis was isolated. Genetic analysis and fatty acid supplementation indicate that the defect occurred in the Delta(12)-desaturation resulting in the absence of cis-linoleic acid and gamma-linolenic acid and in the accumulation of monounsaturated fatty acids. In addition, an unusual fatty acid, trans-linoleic acid (9c,12t-C18:2), which has not been reported previously in this fungus, was found to increase in the mutant. The information gained from the mutant was used to develop the hypothetical pathway of fatty acid desaturation in M. rouxii.

Fatty Acid Desaturases↗
PubMed2001

Nutrition in diabetes mellitus.

Diet is very important in the treatment of diabetes mellitus. An energy deficit of about 500 Kcal per day is recommended for most overweight diabetic patients in order to progressively achieve a weight loss.--According to the most recent recommendations of the Nutrition Study Group of the European Association for the Study of Diabetes, 60 to 70% of the total daily energy should be covered from a combination of carbohydrates and monounsaturated fatty acids with a cis-configuration. The percentage of energy contributed by each may vary according to individual preferences and clinical characteristics. It is, also, important to reduce the intake of saturated and trans unsaturated fatty acids (< 10% total energy). Protein intake should not exceed 20% total energy intake. Rich in fibre and/or antioxidant carbohydrate containing foods (fruits, vegetables, legumes) or those with a low glycaemic index are strongly recommended. Moderate amounts of foods rich in omega 3-fatty acids (mainly oily fish) should be regularly consumed.

Diabetes Mellitus↗
PubMed2004

To what extent are the effects of diet on coronary heart disease lipid-mediated?

BACKGROUND: Cohort and case-control studies support the effect of diet on coronary heart disease. The objective of this study was to analyze the strength of the influence of dietary fat subtypes and other nutrients on serum lipids levels in patients with a first acute myocardial infarction. METHODS: We studied 139 patients with a first myocardial infarction and no previous history of vascular disease. Serum lipids were determined, and nutrient intake was analyzed using a validated 118-food item questionnaire. RESULTS: Multiple regression models found weak but significant associations between the intake of different fatty acids and total to HDL cholesterol ratio (atherogenic index) when we adjusted for age, gender and body mass index (BMI). Positive associations with serum HDL cholesterol concentration were observed for energy-adjusted intake of red wine, alcohol intake, and omega-3 fatty acids intake. However, these nutrients explained less than 12% of the variability in the atherogenic index, and less than 17% in the variability of HDL. CONCLUSIONS: Our results suggest only a modest contribution of the investigated nutrients on serum lipids (atherogenic index and HDL cholesterol) in coronary patients. Alternative mechanisms of dietary factors not directly related with serum lipids or, more likely, a global effect of diet on inflammatory and antioxidant parameters should be studied in order to better understand the nature of dietary habits' influence on cardiovascular disease.

Adult↗
PubMed1993

Interactions of all-trans-retinol and long-chain fatty acids with interphotoreceptor retinoid-binding protein.

Interphotoreceptor retinoid-binding protein (IRBP), a predominant protein in the interphotoreceptor matrix of the retina, has been implicated in transfer of retinoids between retinal pigment epithelium and photoreceptor cells. The interactions of IRBP with all-trans-retinol have been studied by three fluorescence-based methods and by measurements of binding of 3[H]-labeled all-trans-retinol to this protein. It was found that IRBP contains two sites with similar but not identical affinities for all-trans-retinol. The dissociation constant of the all-trans-retinol-IRBP complex at the first site was 0.1 microM, which is about 10-fold lower than previously reported values. The second site had about 2.5-fold lower affinity for all-trans-retinol as compared to the first site. Long-chain fatty acids were found in this study to displace all-trans-retinol from the stronger retinol-binding site on IRBP. Displacement of all-trans-retinol was used to study the interactions of fatty acids with this protein. It was found that docosahexaenoic acid (DHA C22:6n-3), an essential fatty acid which plays an important role in vision, had the highest apparent affinity for the site probed on IRBP of all the fatty acids studied.

Animals↗
PubMed1994

Evidence from in vivo manipulations of lipid composition in mutants that the delta 3-trans-hexadecenoic acid-containing phosphatidylglycerol is involved in the biogenesis of the light-harvesting chlorophyll a/b-protein complex of Chlamydomonas reinhardtii.

The phosphatidylglycerol containing the unusual delta 3-trans hexadecenoic fatty acid is specifically found in photosynthetic membranes of eukaryotic organisms. Its involvement in the biogenesis and the structure of the light-harvesting chlorophyll a/b-protein complex has been evidenced by in vivo targeting this lipid to photosynthetic membranes of Chlamydomonas reinhardtii mutants lacking this lipid. In the mf1 and mf2 mutants, this deficiency results in (a) the absence of the oligomeric light-harvesting complex of photosystem 2; (b) an extensive destacking of thylakoid membranes; (c) a very low 77-K fluorescence emission in the photosystem-2 region. We show in this paper that these deficiencies result from modifications in the pigment and polypeptide compositions of the photosystem-2 light-harvesting complex; it contains less chlorophyll b and some of its constitutive polypeptides are absent or reduced in amount, while immunologically related polypeptides of lower molecular mass accumulate. The direct involvement of the lack of trans-C16: 1-phosphatidylglycerol in these deficiencies is evidenced by the partial restoration of normal characteristics of the light-harvesting complex (pigment and polypeptide composition, oligomerization) after liposome-mediated, in vivo incorporation of this lipid into the photosynthetic membranes of the mf2 mutant. Trans-C16:1-phosphatidylglycerol, therefore, is involved in the biogenesis of the photosystem-2 light-harvesting chlorophyll a/b-protein complex through a mechanism that may prevent degradation processes. Its contribution to the structural conformation of neosynthesized monomers and to their organization into stable oligomeric form is discussed.

Animals↗
PubMed2002

Duodenal and milk trans octadecenoic acid and conjugated linoleic acid (CLA) isomers indicate that postabsorptive synthesis is the predominant source of cis-9-containing CLA in lactating dairy cows.

Duodenal and milk samples obtained from lactating cows in a previous study were analyzed to compare the content and isomer distribution of conjugated linoleic acids (CLA) and trans-18:1 fatty acids (tFA). Four diets containing either low [25 g/100 g dry matter (DM)] or high (60 g/100 g DM) forage were fed with or without 2% added buffer to four multiparous Holstein dairy cows in a 2 x 2 factorial, 4 x 4 Latin square design with 3-wk experimental periods. Duodenal flows of CLA were low (1.02-1.84 g/d), compared with that of tFA (57-120 g/d), regardless of diet. The greatest amounts of CLA and tFA, as well as the greatest proportions of trans-10-18:1 (P < 0.02), and cis-9, trans-11 (P < 0.01) and trans-10, cis-12 CLA (P < 0.01) were in the duodenal flow of cows fed the low forage unbuffered diet. In milk fat, tFA were increased by the low forage unbuffered diet and the trans-10-18:1 (P < 0.02) replaced trans-11-18:1 as the major 18:1 isomer. Milk CLA secretion (7.2-9.1 g/d) was greater (P < 0.001) than that in the duodenal flow with each diet. This was due to the increase in cis-9, trans-11-18:2 and trans-7, cis-9 CLA, resulting most likely from endogenous synthesis via Delta9-desaturation of ruminally derived tFA. For other CLA isomers, duodenal flow was always greater than milk secretion, suggesting that they essentially were produced in the rumen.

Animal Feed↗
PubMed2000

The effect of dietary trans alpha-linolenic acid on plasma lipids and platelet fatty acid composition: the TransLinE study.

OBJECTIVE: To collect (i) baseline data and (ii) execute a large multicentre study examining the effect of trans alpha-linolenic acid on its incorporation into plasma lipids and on risk factors for coronary heart disease. DESIGN: Male volunteers were recruited and the habitual diet assessed by a 4-d weighed record. Fatty acid composition of plasma and platelet lipids were determined by gas chromatography at baseline. After a 6 week run-in period on a trans 'free' diet, male volunteers were randomised to consume 0.6 % of energy trans alpha-linolenic acid or to continue with a diet 'low' in trans alpha-linolenic acid for 6 weeks. SETTING: Three European university research departments supported by the research and development departments of the food industry. SUBJECTS: Male volunteers (88) recruited by local advertisement. METHODS: Replacement of 30 % of the fat of the habitual diet by margarine, oil and foods. Rapeseed oil was deodorised especially to produce the trans 'free' and 'high' trans foods for this study. The incorporation and conversion of trans alpha-linolenic acid into plasma lipids and platelets was assessed by gas chromatography and dietary compliance was verified by 4-d weighed record. RESULTS: Less trans alpha-linolenic acid isomers are incorporated into human plasma lipids in French volunteers than in Dutch or Scottish volunteers consuming their habitual diets. Trans 'free' alpha-linolenic acid-rich oil can be produced by careful deodorization during refining. The 'high' trans diet provided 1410+/-42 mg/d trans isomers of alpha-linolenic acid, whilst the 'low' trans group consumed 60+/-75 mg/d. The change in plasma lipid and platelet fatty acid composition documented that trans linolenic isomers are incorporated and converted to a trans isomer of eicosapentaenoic acid. Only the 15-trans alpha-linolenic acid is incorporated into plasma cholesteryl esters. The group consuming low trans diet had a slightly higher intake of fat, especially saturated and monounsaturated fat. CONCLUSIONS: Trans 'free' rapeseed oil, rich in alpha-linolenic acid, can be produced by careful deodorization. Dietary records show good compliance. Dietary trans isomers of alpha-linolenic acid are incorporated in plasma lipids and converted to long-chain polyunsaturated fatty acids. Their effects on risk factors for coronary heart disease and their metabolism will be reported elsewhere. SPONSORSHIP: European Commission (FAIR 95-0594 grant). European Journal of Clinical Nutrition (2000) 54, 104-113

Adult↗
PubMed1977

Qualitative and quantitative variations of membrane lipid species in Acholeplasma laidlawii A.

In Acholeplasma laidlawii A, strain EF 22, the relative amounts of the membrane polar lipids vary as a consequence of different fatty acid supplements to the growth medium. The number of lipid species also varies; a new apolar monoglucolipid containing four fatty acid residues was present only when saturated fatty acids dominated in the growth medium. A new phosphoglucolipid, probably with a glycerophosphoryl-monoglucosyldiglyceride structure, was also found. The most pronounced variations occurred between the two dominating glucolipids, monoglucosyldiglyceride and diglucosyldiglyceride; the former being found in larger amounts when a saturated or a trans-unsaturated fatty acid was present in the medium. The amount of diglucosyldiglyceride decreased accordingly. A qualitative relationship between fatty acid properties and membrane lipid variations was established over a wide fatty acid concentration range. Incorporation of supplied fatty acids reached higher levels than normally found in other acholeplasmas. The ratio between membrane protein and lipids exhibited significant and coherent variations during growth and was to some extent influenced by the fatty acids in the medium. These changes indicate variations in lipid-protein organization in the membranes during growth.

Acholeplasma laidlawii↗