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Trans fatty acids promote the growth of some Lactobacillus strains.

Five Lactobacillus strains (2 L. gasseri, 2 L. plantarum and 1 L. reuteri) were cultured in modified MRS medium containing fatty acids (FAs) instead of Tween 80 for 24 h at 37 degrees C, to learn the effect of saturated and unsaturated FAs on the Lactobacillus growth. Free FAs included palmitic (16:0), palmitoleic (c9-16:1), stearic (18:0), oleic (c9-18:1), elaidic (t9-18:1), cis-vaccenic (c11-18:1), vaccenic (t11-18:1), linoleic (c9, c12-18:2), conjugated linoleic (c9, t11- and t10, c12-18:2), alpha-linolenic (c9, c12, c15-18:3), alpha-eleostearic (c9, t11, t13-18:3), eicosapentaenoic (20:5), and docosahexaenoic (22:6) acids. Among free FAs, oleic acid stimulated the growth of all Lactobacillus strains, whereas palmitoleic acid had almost no affect on the Lactobacillus growth. Saturated FAs such as stearic and palmitic acids inhibited or did not affect the Lactobacillus growth. Polyunsaturated FAs such as alpha-linolenic, eicosapentaenoic and docosahexaenoic acids strongly inhibited the Lactobacillus growth at 7.6 x 10(-4) m. Octadecenoic acids such as oleic, elaidic, cis-vaccenic and vaccenic acids remarkably promoted the growth of L. gasseri, regardless of the different double bond positions and configurations. When oleic or cis-vaccenic acid was incubated with L. gasseri, the FAs was transformed to cyclopropane FAs (methyleneoctadecanoic acids) after incorporation into the cells. On the other hand, trans FAs such as elaidic and vaccenic acids incorporated into the cells were not converted to another FAs. Conjugated linoleic and alpha-eleostearic acids having a trans double bond promoted the Lactobacillus growth. The growth of L. gasseri was also stimulated by trans-rich free FAs from hydrogenated canola and fish oils. These results showed that octadecenoic acid and trans FAs had strong promotion activities for the Lactobacillus growth due to their incorporation into membrane lipids.

Anti-Bacterial Agents↗

Dietary fatty acids affect plasma markers of inflammation in healthy men fed controlled diets: a randomized crossover study.

BACKGROUND: The effect of individual dietary fatty acids on emerging risk factors for cardiovascular disease that are associated with subclinical inflammation is unknown. OBJECTIVE: The goal was to evaluate the role of dietary fat and specific fatty acids, especially trans fatty acids, in altering concentrations of markers of inflammation in humans fed controlled diets. DESIGN: In a randomized crossover design, 50 men consumed controlled diets for 5 wk that provided 15% of energy from protein, 39% of energy from fat, and 46% of energy from carbohydrate. Eight percent of fat or fatty acids was replaced across diets with the following: cholesterol, oleic acid, trans fatty acids (TFAs), stearic acid (STE), TFA+STE (4% of energy each), and 12:0-16:0 saturated fatty acids (LMP). RESULTS: Fibrinogen concentrations were higher after consumption of the diet enriched in stearic acid than after consumption of the carbohydrate diet. C-reactive protein concentrations were higher after consumption of the TFA diet than after consumption of the carbohydrate diet, but were not significantly different after consumption of the TFA and TFA+STE diets than after consumption of the LMP diet. Interleukin 6 concentrations were lower after consumption of the oleic acid diet than after consumption of the LMP, TFA, and STE diets. E-selectin concentrations were higher after consumption of the TFA diet than after consumption of the carbohydrate diet. Consumption of the TFA but not the TFA+STE diet resulted in higher E-selectin concentrations than did the LMP diet. CONCLUSIONS: These data provide evidence that dietary fatty acids can modulate markers of inflammation. Although stearic acid minimally affects LDL cholesterol, it does appear to increase fibrinogen concentrations.

Adult↗

Positional specificity of trans fatty acids in fetal lecithin.

Differences in the positional incorporation of 9-trans[1-(14)C] octadecenoic (elaidic) and 9-trans,12-trans[1-(14)C] octadecadienoic (linoelaidic) acids in fetal lecithin of rats were demonstrated. On the 20th day of gestation, a 14C-labeled albumin complex of elaidic or linoelaidic acid was injected into the jugular vein of pregnant rats. For comparative purposes, 9-cis[1-(14)C] octadecenoic (oleic) or 9-cis,12-cis[1-(14)C] octadecadienoic (linoleic acid) was injected into the maternal circulation of rats. Animals were killed 6 hr later. Distribution of label in total lipids and phospholipids (PL) of fetal issue was measured by TLC. Irrespective of the label, the highest percentage of total radioactivity was associated with PL-59 to 67%. Within PL, the major portion of radioactivity was found in choline phosphoglycerides (CPG)-53 to 67%, and in ethanolamine phosphoglycerides (EPG)-18 to 33%. While linoelaidic acid was predominantly esterified in the 2-position of CPG, elaidic acid was nearly equally distributed between positions 1 and 2 of lecithin. Distribution of radioactivity within fatty acid methyl esters (FAME) of CPG measured by radio-GLC suggested that oleic and possibly linoleic acids may be converted to nervonic and arachidonic acid, respectively, in the rat by the 20th day of gestation. Following injection of elaidate, radioacivity of FAME was distributed between palmitate and elaidic acid indicating that rat fetal tissue may metabolize elaidic acid via beta-oxidation. In contrast, following injection of linoelaidate, radioactivity of FAME was primarily associated with tt-18:2, suggesting little biotransformation to other fatty acids by fetal tissues.

Animals↗

Estimated intakes of trans fatty and other fatty acids in the US population.

OBJECTIVE: To estimate mean level of trans fatty acid intakes using a representative sample of the US population. DESIGN: The study used food intake data from the 1989-1991 Continuing Survey of Food Intakes by Individuals (CSFII) and the trans fatty acid contents of specific foods calculated from a database compiled by the US Department of Agriculture (USDA) to estimate the mean level and deciles of trans fatty acid intake of the representative US population. SUBJECTS/SETTING: Trans fatty acid intakes were estimated for each subject (N = 11,258) in the CSFII data who completed both a 24-hour recall and a 2-day food record. STATISTICAL ANALYSES PERFORMED: Weights developed by USDA for the survey were used for all data analyses. The Technical Assessment Systems (TAS) International Diet Research System (TAS-DIET), software developed by TAS, was used to derive weighted estimates of the mean and percentiles of the intake distribution. PC CARP, software designed by Iowa State University, was used to estimate standard errors. RESULTS: Mean percentage of energy ingested as trans fatty acids was 2.6% and the mean percentage of total fat ingested as trans fatty acids was 7.4%. Across all age and gender groups examined, estimates ranged from 2.6% to 2.8% and 7.1% to 7.9%, respectively. APPLICATIONS/CONCLUSIONS: Dietetics practitioners can use the representative data of this study to help clients achieve desired changes in consumption levels of trans fatty acids.

Adolescent↗

Effects of dietary saturated and trans fatty acids on cholesteryl ester synthesis and hydrolysis in the testes of rats.

Studies were made of the enzymic synthesis and hydrolysis of cholesteryl esters in rat testes. Weanling rats were fed for 14 weeks diets containing 5% by wt of hydrogenated coconut oil (HCO), a concentrate of ethyl elaidate and linolelaidate (TRANS), devoid of essential fatty acids (EFA), or safflower oil (SAFF). Cholesterol esterifying activity was localized in the soluble fraction, and cholesteryl ester hydrolase activity was distributed in both particulate and soluble fractions obtained from tissue homogenates. The optimum pH was 6.0 for esterification and 6.9-7.0 for hydrolysis. Neither esterifying nor hydrolytic activity was affected by freezing and thawing, but both reactions were inhibited by heat or sonication. The animals of both the HCO and TRANS groups had developed an EFA deficiency before they were sacrificed. The EFA deficiency produced upon feeding the HCO diet had no apparent effect on the synthesis and hydrolysis of cholesteryl esters in rat testes. The TRANS diet influenced the development of the testes as judged by their size, and cholesterol esterifying and cholesteryl ester hydrolyzing activities were suppressed in the testes of the animals of this group. A major difference in the effects of the HCO and TRANS diets on the lipids of the tests was the relatively minor amount of eicosatrienoic acid (20:3) and the elevated level of docosapentaenoic acid (22:5) in the cholesteryl esters of the testicular lipids of the TRANS group.

Animals↗

Trans fatty acids: transport and positional specificity in rat placental lecithin.

Differences in positional incorporation of trans and cis isomers of octadecenoic and octadecadienoic acids in placental lecithin of rats was demonstrated. A 14C-labeled albumin complex of elaidic, oleic, linoelaidic, or linoleic acid was injected into the jugular vein of pregnant rats. 6 h later 45-64% of the total radioactivity in placental lipids was found in phospholipids (PL), with a major portion of the label incorporated into choline phosphoglycerides (CPC). Following hydrolysis of placental CPC by phospholipase A2, distribution of radioactivity within isolated fatty acids and lysolecithin suggested preferential incorporation of t,t-18:2 at position 2 and a nearly equal distribution of t-18:1 at positions 1 and 2.

Animals↗

Trans fatty acids: a cause for concern?

The recommendation to reduce total and saturated fat is incorporated into the dietary guidelines for the general population in many western countries. In addition, dietary modification to reduce substantially the intake of saturated fats is a cornerstone of treatment in the hyperlipidaemias. Concern has recently been expressed regarding possible deleterious effects of trans isomers of unsaturated fatty acids on the lipoprotein profiles of both normo and hypercholesterolaemic persons. This review seeks to examine recent research in this area with a view to considering possible changes in the present dietary recommendations.

Coronary Disease↗

Influences of biotin deficiency and dietary trans-fatty acids on tissue lipids in chickens.

1. The combined effects of feeding hydrogenated fats and varying the levels of biotin and linoleate (18:2 omega 6) on polyunsaturated fatty acids were studied in the chicken. 2. Biotin deficiency signs were not exacerbated by feeding hydrogenated fats or by diets low in linoleate for 21 d. 3. Biotin deficiency resulted in proportionately higher levels of 18:2 omega 6 and gamma-linolenate (18:3 omega 6) in liver triglycerides, and lower levels of dihomo-gamma-linolenate (20:3 omega 6) in liver and heart phospholipids irrespective of the 18:2 omega 6 level in the diet. 4. Biotin deficiency did not alter arachidonate (20:4 omega 6) levels in tissue lipids at 21 d. 5. Feeding high levels of trans-18:1 isomers with adequate biotin led to reduced 20:3 omega 6 and 20:4 omega 6 levels in liver and heart phospholipids with compensatory increases in omega 3 fatty acids. 6. The trans-isomers of 18:1 were incorporated into several tissues of the chick. Incorporation was dependent on the levels fed. Very small amounts were incorporated into brain compared with other tissues when dietary trans-isomer levels were high, but were similar when dietary trans-isomer levels were low. The trans-18:1 isomers appear to be preferentially incorporated into phospholipids as opposed to triglycerides in heart and liver.

Animals↗

A shift from phospholipid to triglyceride synthesis when cell division is inhibited by trans-fatty acids.

The yeast mutant Saccharomyces cerevisiae (KD 46) requires added unsaturated fatty acid for growth. When cell growth was inhibited by the presence of trans-acids there was a marked inhibition of oleate esterification into phospholipids accompanying continued incorporation into triglycerides. Apparently some control point in phospholipid synthesis associated with the cell cycle occurs after the stage of phosphatidate biosynthesis.

Cell Division↗

Differential effects of cis and trans fatty acid isomers, oleic and elaidic acids, on the cholesteryl ester transfer protein activity.

In a previous publication (Lagrost, L. and Barter, P.J. (1991) Biochim. Biophys. Acta 1085, 209-216), saturated and cis unsaturated non-esterified fatty acids have been shown to modulate the rate at which cholesteryl esters are transferred from high-density lipoproteins (HDL) to low-density lipoproteins (LDL) in the presence of the human cholesteryl ester transfer protein (CETP). In the present report, the effects of cis (oleic acid) and trans (elaidic acid) monounsaturated isomers on the CETP-mediated transfer of cholesteryl esters between HDL and LDL were compared. Mixtures of human LDL and HDL3, containing or not radiolabelled cholesteryl esters, were incubated at 37 degrees C with CETP in the presence or in the absence of either stearic (18:0), oleic (18:1 cis) or elaidic (18:1 trans) acids. It was observed that oleic acid and elaidic acid had different effects on the CETP-mediated redistribution of radiolabelled cholesteryl esters as well as on the net mass transfer of cholesterol from HDL3 to LDL. In particular, at high non-esterified fatty acid/lipoprotein ratio, the transfer of cholesteryl esters was significantly inhibited by the cis isomer and increased by the trans isomer.

Biological Transport↗

Incorporation of trans fatty acids into submandibular salivary gland lipids.

Three groups of rats were fed diets containing 20% corn oil, 20% margarine stock (MS) or 19% MS + 1% corn oil. Diets were fed for 12 weeks, 1 week of pregnancy, 3 weeks of lactation and 8 weeks post-weaning. The incorporation of trans-octadecenoate into various lipids of the submandibular salivary gland (SMSG) homogenates and plasma membranes was studied. Trans octadecenoate was incorporated into all the lipid fractions studied. Its levels were the highest in phosphatidylethanolamine. The double bond index of phospholipid fatty acids in the plasma membranes of the SMSG was substantially lower in the group fed 20% MS. The fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) was generally higher in the membranes of SMSG from rats fed MS than that of the other two groups, thus indicating lower fluidity. Also, the breakpoints in fluorescence polarization were at a higher temperature in the membranes from rats fed MS as compared with those fed corn oil. Lower fluidity of plasma membranes of SMSG observed in rats fed 20% MS may result in modification of the activities of membrane-bound enzymes.

Animals↗

Temperature-sensitive resolution of cis- and trans-fatty acid isomers of partially hydrogenated vegetable oils on SP-2560 and CP-Sil 88 capillary columns.

This study examines the effect of the column operating temperature of 100 m SP-2560 and CP-Sil 88 capillary gas chromatographic (GC) columns on the separation of cis- and trans-octadecenoic (18:1) isomers in partially hydrogenated vegetable oils. The overlapping GC peaks were measured at column isothermal temperatures of 170, 175, 180, 185, and 190 degrees C. With both columns, isothermal operation at 180 degrees C produced the fewest overlapping peaks of the cis and trans isomers. At this temperature, all trans-18:1 isomers, except 13t-18:1 (t = trans), 14t-18:1, and 15t-18:1 isomers were resolved from the cis-18:1 isomers. The peaks of the 13t-18:1 and 14t-18:1 isomer pair, which always elute together, overlapped peaks of the 6c-18:1 (c = cis), 7c-18:1, and 8c-18:1 isomers; the peak of the 15t-18:1 isomer overlapped the major cis-18:1 peak, which was mainly due to 9c-18:1. Isothermal operations above or below 180 degrees C produced some additional overlapping problems. At 185 and 190 degrees C, the peaks of the 16t-18:1 and 13c-18:1 isomers overlapped. At 175 and 170 degrees C, the 16t-18:1 peak overlapped the 14c-18:1 peak, and the peaks of the 13t + 14t-18:1 isomer pair partially overlapped the major cis-18:1 peak. The separation of 11c-20:1 and alpha-linolenic acid and its geometric isomers was also affected by the column operating temperature. Isothermal operation of the SP-2560 column at 180 degrees C produced a baseline separation of 11c-20:1 and alpha-linolenic acid and its geometric isomers, whereas with the CP-Sil 88 column the best resolution was obtained at 170 degrees C. The results of this study show that the SP-2560 capillary column has a slight advantage over the CP-Sil 88 column for the simultaneous resolution of all the fatty acids generally found in partially hydrogenated vegetable oils.

Chromatography, Gas↗