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PubMed1994

Structure-activity relationships of unsaturated long chain fatty acids in relation to the inhibition of gastric H+,K(+)-ATPase.

Structure-activity analyses of the effects of unsaturated fatty acids on the inhibition of gastric H+,K(+)-ATPase were carried out. Saturated fatty acids are poor inhibitors of H+,K(+)-ATPase, compared with unsaturated ones. Among the cis-unsaturated fatty acids with one double bond, there was an optimal carbon chain length for the inhibitory of the enzyme, and 10-nonadecenoic acid (C19:1) was the most potent inhibitor. The inhibitory activity was not altered by a change in the position of the double bond. The cis-fatty acids were more potent than the corresponding trans-fatty acids. Esterification of the acid moiety resulted in a decrease of the inhibitory activity. However, conversion of the acid moiety into alcohol and amide did not decrease the activity. These findings suggest that two moieties of unsaturated fatty acids are important in the interaction with the gastric H+,K(+)-ATPase, the carbon chain, which may have some hydrophobic interactions with the enzyme, and the terminal functional group (acid moiety), which may interact with hydrophilic interactions such as through hydrogen bonds with the enzyme.

Animals↗
PubMed1979

Incorporation of cis- and trans-octadecenoic acids into the membranes of rat liver mitochondria.

The incorporation of dietary isomeric fatty acids into the membranes of liver mitochondria was investigated. Three groups of rats were fed diets containing 3% sunflower seed oil plus 15%, 20%, or 25% partially hydrogenated arachis oil. A fourth group was fed 25% partially hydrogenated arachis oil, but no sunflower seed oil. All diets were given for 3, 6, or 10 weeks. After 10 weeks, the content of trans fatty acids in the lipids of the mitochondrial membranes was 15--19% of the total fatty acids. The composition of the trans- and the cis-octadecenoic acids in the lipids of the mitochondrial membranes was similar for all groups supplemented with sunflower seed oil (SO), irrespective of time and dietary level of partially hydrogenated arachis oil (HAO). The cis 18:1 (n-8), which was a major isomer of the partially hydrogenated arachis oil, was almost excluded from the mitochondrial fatty acids. Likewise, the content of trans 18:1 (n-8) was considerably lower in the mitochondrial lipids than in the diet. On the contrary, the content of trans 18:1 (n-6) was higher in the mitochondrial lipids than in the diet. In the group fed without sunflower seed oil, isomers of linoleic acid and arachidonic acid were observed in the lipids of mitochondrial membranes.

Animals↗
PubMed2005

Dietary intake of fatty acids, antioxidants and selected food groups and asthma in adults.

OBJECTIVE: Within a prospective study, we explored the associations between dietary intake of fatty acids, antioxidants and relevant food sources of these nutrients on the clinical manifestation of asthma in adulthood. METHOD: A total of 105 newly physician-diagnosed cases of asthma from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Heidelberg cohort were identified during follow-up and matched with 420 controls. Baseline dietary intake was obtained by means of validated food frequency questionnaires. The association of dietary intake variables and asthma risk was explored by unconditional logistic regression models. RESULTS: A high intake of oleic acid (C18:1 n-9) was positively associated with asthma (P-value for trend 0.035), while no significant associations were found for the other dietary fatty acids. Most prominently, a high margarine intake increased the risk of onset of asthma in adulthood (adjusted odds ratio (OR) 3rd tertile: 1.73 (95% confidence interval (95% CI): 1.05-2.87), P for trend=0.050), the effect being stronger in men (2nd tertile: OR=1.66, 3rd tertile: OR=2.51) than in women (2nd tertile: OR=0.91; 3rd tertile: OR=1.47). The dietary intake of antioxidants and their main food sources had no effect on asthma risk. CONCLUSIONS: In summary, the present results provide evidence that even in adulthood a high margarine intake increases the risk of clinical onset of asthma. Whether oleic acid may serve as a proxy for margarine-derived trans-fatty acids (C18:1 t9) remains to be clarified.

Adult↗
PubMed1986

The Eskimo diet. Prophylactic effects ascribed to the balanced presence of natural cis unsaturated fatty acids and to the absence of unnatural trans and cis isomers of unsaturated fatty acids.

In addition to the well recognised roles of eicosapentaenoic acid and possibly docosahexaenoic acid, there are two other major important, but unrecognised, features of the traditional Eskimo staple diet namely that it contains the unsaturated fatty acids (UFA) cis oleic, cis linoleic and cis alpha-linolenic as well as their respective C20 and C22 metabolites in physiologically optimal concentrations and, it is virtually totally devoid of unnatural and potentially hazardous trans and cis isomers of these fatty acids. Large quantities of unnatural trans and cis isomers of UFA are found in the Western diet as partially hydrogenated UFA in many foods. These isomers are formed during the manufacture of margarines and related compounds, as food contaminants during excessive heating of cooking oils for deep-frying and other excessive heat-requiring mass food preparation procedures and it is suggested, as the result of excessive feeding with an unnatural diet of ruminants and non-ruminants for increased meat and/or milk production and of poultry for increased egg and/or meat production. These isomers have been shown to display potentially hazardous metabolic effects which include the competitive inhibition of UFA metabolism at various steps and have been causally implicated in the etiology of ischemic heart disease and cancer. It is suggested that the myth of the safety of trans fatty acids arises from misinterpretation of the observation that increasing dietary cis linoleic acid reduces the toxic effects of trans UFA. It is suggested that the decrease of 20% in the ischemic heart disease mortality in the USA during the past two decades is directly related to a shift in the dietary ratio of unnatural trans and cis UFA isomers: cis linoleic acid in favour of the latter. It is predicted that this ratio will be found to correlate with ischemic heart disease patterns in other countries. Eskimos consume the bulk of their food frozen, raw or dried, seldom boiled, but never deep-fried or after exposure to excessive heat. Moreover the proportionality of cis UFA and their metabolites in their traditional staple diet would render gross tissue UFA utilization relatively independent of desaturase enzyme activity. In the Eskimo tissues these enzymes would function to make the minute, critical UFA metabolic adjustments required to ensure the presence of structural UFA in membranes in functionally optimal quantities and, ensure the synthesis of eicosanoids from dihomogamma-linolenic acid, arachidonic acid and eicosapentaenoic acid in balanced, optimal physiological concentrations for the genetic make-up of Eskimos.(ABSTRACT TRUNCATED AT 400 WORDS)

Dietary Fats↗
PubMed1981

Content of trans-octadecenoic acid in vegetarian and normal diets in Sweden, analyzed by the duplicate portion technique.

The intake of trans fatty acids by subjects adhering to the normal Swedish diet or to different vegetarian regimes was studied, using chemical analysis of duplicate portions. Trans-octadecenoic acid was 5.0, 3.9, and 1.8% of dietary fatty acid in the normal, lactovegetarian, and vegan diets, respectively, corresponding to 2.0, 1.3, and 0.5% of energy intake. The results are related to the content of trans-octadecenoic acid in some edible fats.

Butter↗
PubMed2000

Quantitative analysis of long-chain trans-monoenes originating from hydrogenated marine oil.

Gas chromatography (GC) is used for the analysis of trans-fatty acids in partially hydrogenated vegetable oils. Although trans-isomers of C18 carbon length predominate in partially hydrogenated vegetable oils, trans-isomers of C20 and C22 carbon length occur in partially hydrogenated fish oil. We report a simple silver ion chromatographic combined with capillary GC technique for quantitative analysis of trans-monoenes derived from partially hydrogenated fish oil. Silver nitrate thin-layer chromatographic (TLC) plates are developed in toluene/hexane (50:50, vol/vol). Fatty acid methyl esters are separated into saturates (Rf 0.79), trans-monoenes (Rf 0.49), cis-monoenes (Rf 0.27), dienes (Rf 0.10), and polyunsaturated fatty acids with three or more double bonds remaining at the origin. The isolated trans-monoenes are quantitatively analyzed by capillary GC. The technique of argentation TLC with GC analysis of isolated methyl esters is highly reproducible with 4.8% variation (i.e., coefficient of variation, CV%) in R. values and 4.3 and 6.9% CV% in quantification within batch and between batch, respectively. Furthermore, the combined technique revealed that direct GC analysis underestimated the trans-content of margarines by at least 30%. In this study, C20 and C22 trans-monoenes were found in relatively large quantities; 13.9% (range 10.3-19.6%) and 7.5% (range 5.3-11.5%), respectively, in margarine purchased in 1995, but these C20 and C22 trans-monoenes were much reduced (0.1%) in a fresh selection of margarine purchased in 1998. Compositional data from labels underestimated the trans-content of margarines, especially those derived from hydrogenated marine oil. Low levels of C20 transmonoenes (range 0.1-0.3%) and C22 trans-monoenes (range 0.0-0.1%) were identified in adipose tissue obtained from healthy volunteers in 1995, presumably indicating consumption of partially hydrogenated fish oil.

Adipose Tissue↗
PubMed1976

trans-6-Hexadecenoic acid in the spadefish Chaetodipterus faber.

Fatty acid methyl esters were prepared from spadefish (Chaetodipterus faber) liver oil and were analyzed by open tublar gas chromatography. The unusual fatty acid trans-6-hexadecenoic acid was identified as a major monoenoic component by reductive ozonolysis and by mass spectrometry of the di-trimethylsilyl ether. Very minor amounts of 7-methyl-7-hexadecenoic acid were found.

Animals↗
PubMed2005

Fatty acids and atherosclerotic risk.

Most research concerning the effects of dietary fatty acids on atherosclerotic risk has focused on their effects on lipid and lipoprotein metabolism. However, it is known that fatty acids also influence a number of other relevant mechanisms involved in atherosclerosis such as lipid peroxidation, inflammation and haemostasis. The most favourable distribution of cholesterol over the various lipoproteins is achieved when saturated and trans fatty acids are replaced by a mixture of cis-unsaturated fatty acids. Furthermore, fatty acids from fish oil lower triacylglycerol concentrations. Effects on other atherosclerotic risk markers are less evident. Monounsaturated fatty acids maybe preferable above other fatty acids with respect to low-density lipoprotein oxidation as measured by indirect in vitro assays. The relevance of these assays for the in vivo situation is, however, limited. With respect to inflammation, mainly the effects of n-3 polyunsaturated fatty acids from fish oil have been studied, but results were inconsistent. Also results from studies evaluating the effects of fatty acids on haemostatic risk markers were inconsistent, which may be partly related to the use of different analytical methods. The most consistent finding however is the potential beneficial effect of moderate intakes of fish oil on platelet aggregation. Furthermore, reducing total fat intake rather than changing the fatty acid composition of the diet may beneficially affect the coagulation system. In conclusion, while beneficial effects on atherosclerotic risk are mainly ascribed to cis-unsaturated fatty acids, it remains debateable whether trans and saturated fatty acids in the diet have to be replaced by cis-unsaturated fatty acids or by carbohydrates. To answer this question adequately more validated methods are needed that reflect in vivo lipid peroxidation, inflammation and haemostasis.

Animals↗
PubMed1997

Effect of dietary forage concentration and buffer addition on duodenal flow of trans-C18:1 fatty acids and milk fat production in dairy cows.

Milk fat depression in cows fed high grain diets has been shown to be related to increased trans-C18:1 fatty acids in milk. Trans-C18:1 fatty acids are produced as a result of incomplete biohydrogenation of dietary polyunsaturated fatty acids in the rumen. The objective of this study was to determine the effects of varying amounts of dietary concentrate and buffer addition on duodenal flow, apparent absorption, and incorporation of trans-C18:1 fatty acids into milk fat. Four ruminally and duodenally cannulated multiparous Holstein cows in midlactation were fed diets consisting of 60% (high) or 25% (low) forage with or without buffer (1.5% NaHCO3 and 0.5% MgO). Treatments were arranged in a 2 x 2 factorial within a 4 x 4 Latin square design. The diet containing low forage and no buffer increased the flow of trans-C18:1 fatty acids to the duodenum compared with the effects of other diets (120 vs. 57 to 66 g/d). Ruminal pH was lower for cows fed the low forage diets. The addition of buffer increased ruminal pH by 0.19 and 0.02 units for cows fed the low forage and high forage diets, respectively. Cows fed the diet containing low forage and no buffer produced milk with a lower fat percentage. The addition of buffer to the low forage diet partially corrected milk fat depression. Milk trans-C18:1 fatty acids were higher for cows fed the low forage diet without buffer than for cows fed the other diets (5.8% vs. 3.0%). Altered ruminal function resulting from low ruminal pH for cows fed the low forage diet and no buffer may play a role in the increased production of trans-C18:1 fatty acids in the rumen.

Animal Feed↗
PubMed2001

[Trans isomers of unsaturated fatty acids--metabolic action and clinical effects].

Fatty acids with the trans configuration are formed chiefly during hardening of oils and have been associated with increased risk of ischaemic heart disease. Dietary uptake of such fatty acids increases the level of lipoprotein (a) and LDL cholesterol, at the same time reducing the level of HDL cholesterol in plasma. As the content of saturated fatty acids in margarine is lower than in butter, the former product was for a long time considered as healthier. However, some margarines are rich in trans fatty acids. In other words, the risk of cardiovascular diseases can only be reduced by replacing butter with margarine checked for a low trans fatty acid content. The purpose of this paper was to review the literature dealing with the metabolic actions of trans isomers of unsaturated fatty acids and their clinical effects.

Animals↗
PubMedDate not supplied

Relationship between fatty acids and the endocrine and neuroendocrine system.

Significant interactions exist between fatty acids and the endocrine system. Dietary fatty acids alter both hormone and neuropeptide concentrations and also their receptors. In addition, hormones affect the metabolism of fatty acids and the fatty acid composition of tissue lipids. The principal hormones involved in lipid metabolism are insulin, glucagon, catecholamines, cortisol and growth hormone. The concentrations of these hormones are altered in chronic degenerative conditions such as diabetes and cardiovascular disease, which in turn leads to alterations in tissue lipids. Lipogenesis and lipolysis, which modulate fatty acid concentrations in plasma and tissues, are under hormonal control. Neuropeptides are also involved in lipid metabolism in brain and other tissues. Polyunsaturated fatty acids are also precursors for eicosanoids including prostaglandins, leucotrienes, and thromboxanes, which have hormone-like activities. Fatty acids in turn affect the endocrine system. Saturated and trans fatty acids decrease insulin concentration leading to insulin resistance. In contrast, polyunsaturated fatty acids increase plasma insulin concentration and decrease insulin resistance. In humans, omega3 polyunsaturated fatty acids alter the levels of opioid peptides in plasma. Free fatty acids have been reported to inhibit glucagon release. Fatty acids also affect receptors for hormones and neuropeptides.

Animals↗
PubMed2003

Long-term supplementation of various dietary lipids alters bone mineral content, mechanical properties and histological characteristics of Japanese quail.

The purpose of this study was to investigate the effects of long-term supplementation of fat in the diets on the fatty acid composition, chemical, mechanical, and histological properties of tibial bone. Month-old male Japanese quail were fed a basal diet containing either soybean oil (SBO), hydrogenated soybean oil (HSBO), chicken fat (CF), or menhaden fish oil (FO) at 50 g/kg of the diet and maintained on these diets for 7 mo. Lipid treatments did not affect body weight, food intake, tibial length, or diameter. The FO diet group had the highest percentage of tibial ash, and both the FO and HSBO significantly increased tibial mineral content compared to those given SBO or CF. The type and amount of fatty acids in the diets had a profound influence on fatty acid composition of lipids in tibial cortical bones. Quail fed FO had the highest concentration of (n-3) fatty acids, and those fed SBO were highest in (n-6) fatty acids. The HSBO diet, containing high level of trans-fatty acids, led to the accumulation of these fatty acids in bone. In quail, long-term supplementation of FO or HSBO increased tibial shear force and shear stress and improved histological cortical thickness and density when compared to those given SBO or CF. These results suggest that long-term exposure to a FO or HSBO diet have a significant beneficial effect on bone metabolism.

Animal Feed↗
PubMed2004

Role of membrane lipid fatty acids in cold adaptation.

Psychrophilic and psychrotolerant bacteria have evolved various strategies to adapt to low temperature. One important strategy, which is crucial to the survival of the cell at low temperature, relates to the ability of the cell to modulate the fluidity of the membrane. Bacteria in general modulate membrane fluidity by altering their fatty acid composition. But, bacteria could also achieve the same by various other strategies such as by altering the lipid head group, the protein content of the membrane, the type of carotenoids synthesized, the fatty acid chain length and the proportion of cis to trans fatty acids. In addition bacteria have a two-component signal transduction pathway consisting of a membrane-bound sensor and a soluble cytoplasmic response regulator involved in the perception and transduction of low temperature signals. This review on cold adaptation highlights the various strategies by which bacteria modulate the fluidity of the membrane and the process by which it senses and transduces the low temperature signal.

Adaptation, Physiological↗
PubMed1995

Relationships between nutrient intake and progression/regression of coronary atherosclerosis as assessed by serial quantitative angiography.

To elucidate the direction and magnitude of effects of nutrition on coronary artery disease (CAD), the relation between nutrient intake and angiographic changes were examined in the course of a controlled dietary trial. Ninety men with symptomatic CAD and serum cholesterol greater than 232 mg/dL were entered into a randomized controlled trial of a lipid-lowering diet, or of diet plus cholestyramine, compared with usual cardiac care. Of those in the first and second groups, 50 patients completed the trial and are the subject of this report. Quantitative coronary angiography was performed at baseline and at 39 months. From repeated dietary assessment during the trial, mean nutrient intakes were computed, and their relationships with change of coronary artery narrowing were analyzed. Progression of coronary disease was directly, strongly and independently associated with intake of saturated fatty acids of chain length 14-18. This was not fully explained by the effects of saturated fat in raising serum cholesterol; after adjustment for low density lipoprotein cholesterol level, stearic acid (C18:0) intake remained independently predictive of progression. No 'protective' effect of linoleic, linolenic or eicosapentaenoic acid was demonstrable. Intake of trans fatty acids was directly related to progression. Together with the favourable treatment effects on angiographic appearance and clinical end-points, these findings provide further support for a causal role of saturated fats in CAD; restriction of foods containing such fats should be emphasized as part of regimens aimed to reduce progression of coronary atherosclerosis.

Adult↗
PubMed1994

Steady-state fluorescence polarization study of structurally defined phospholipids from liver mitochondria of rats fed elaidic acid.

In vivo-modified phospholipids from rat liver mitochondria were used to study the effect of trans-fatty acid incorporation into phospholipids on the steady-state fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) embedded in phospholipid liposomes. Pure fractions of mitochondria phospholipids were prepared and analyzed for their fatty acid compositions and fatty acid positional distribution. In rats fed a diet enriched with trielaidin, elaidic acid (trans-9 18:1 acid) was extensively incorporated in position 1 of phosphatidylcholine (PC; 31% of fatty acids esterified to this position), phosphatidylethanolamine (PE; 42.5%) and phosphatidylinositol (PI; 43%). Less than 10% of the incorporated elaidic acid was esterified to position 2 of these phospholipids. More than 90% of elaidic acid esterified to position 1 displaced saturated acids. Consequently, about one-third of PC molecules and two-fifths of PE and PI molecules contained one molecule of elaidic acid instead of one saturated fatty acid molecule in their 1-position. On the other hand, cardiolipin, which is naturally practically devoid of saturated acids, was particularly resistant to elaidic acid incorporation. The fluorescence polarization of DPH incorporated in liposomes made of PC-PI and of PC-PI-PE from liver mitochondria of rats fed or not fed elaidic acid was measured. No significant differences between phospholipids containing or not containing elaidic acid could be detected. Values of DPH fluorescence polarization for all samples were comprized between 0.133 and 0.135 at 25 degrees C. We thus conclude that when elaidic acid replaces saturated fatty acids in phospholipids, even in a high proportion (one-third), the physical state of acyl chains in the hydrophobic core of membranes is not grossly modified. Thus, elaidic acid seems to behave like a saturated fatty acid, not only biochemically for the acylation of phospholipids, but also physically.

Animals↗
PubMed2006

The conversion efficiency of trans-11 and trans-12 18:1 by Delta9-desaturation differs in rats.

The present study evaluated and compared the efficiency of the conversion of t11 18:1 and t12 18:1 to their corresponding dienoic acids (c9,tn 18:2) and assessed whether differences due to gender existed in several tissues of rats. Three groups of 4-wk-old male and female rats were fed for 3 wk a diet supplemented with 0, 0.5, or 1% of a trans-octadecenoic acid isomer mixture (tOIM) containing t11 18:1 and t12 18:1 in equal proportion. t11 18:1 and t12 18:1 were incorporated in a tissue-specific manner, and the accrual was significant with increased dietary intake of these trans fatty acid (tFA) isomers. The t12 18:1 isomer was more readily incorporated into the rat tissues than the t11 18:1 isomer. From t11 and t12 18:1, the respective desaturase products, c9,t11 18:2 and c9,t12 18:2, were formed. The calculated conversion rates varied greatly among the tissues of the rats but they were consistently lower for t12 18:1 than for t11 18:1, suggesting that t12 18:1 is a poorer substrate than t11 18:1 for Delta9-desaturase. For both fatty acids investigated, the calculated conversion rates in decreasing order of conversion efficiency were: testes = kidneys > adipose tissue > ovaries > muscle > liver > heart. Overall, there were distinct differences in the conversion of t11 18:1 and t12 18:1, indicating that these 2 fatty acids are metabolized differently despite their structural similarities. Such metabolic differences in tFA accumulation and metabolism may have potential implication in assessing the safety of these tFA isomers because there is a positive correlation between the intake of tFA and the incidence of various diseases.

Animals↗
PubMed2005

Mechanisms by which dietary fatty acids modulate plasma lipids.

Dietary fatty acids have a considerable effect on plasma LDL cholesterol (LDL-C) concentrations and therefore on the risk for coronary heart disease. Numerous studies have been conducted in animal models to elucidate the mechanisms by which different types of fatty acids modulate plasma cholesterol concentrations. In addition, multiple clinical trials and epidemiological data have demonstrated the effects of fatty acids in determining the concentrations of circulating LDL. SFAs and trans fatty acids have a detrimental effect on plasma lipids, whereas PUFAs of the (n-6) family and monounsaturated fatty acids decrease plasma LDL-C concentrations. Among the SFAs, stearic acid (18:0) appears to have a neutral effect on LDL-C, while lauric (12:0), myristic (14:0), and palmitic (16:0) acids are considered to be hypercholesterolemic. SFAs increase plasma LDL-C by increasing the formation of LDL in the plasma compartment and by decreasing LDL turnover. Although unsaturated fatty acids increase cholesterol synthesis, they also increase hepatic LDL receptor number and LDL turnover in vivo. Fatty acids are also ligands of important regulatory elements, which can play a role in determining plasma cholesterol. This article presents a summary of the major effects of various types of fatty acids on plasma lipid concentrations and the mechanisms involved.

Animals↗
PubMed2006

Gender differences in plasma lipid response to dietary fat.

The relationship between type of dietary fat, cardiovascular disease risk, and lipid/lipoprotein profiles has been studied since the early 1900s. For the most part, observational data from international comparisons, migration studies, and prospective studies have identified a positive relationship between saturated fatty acid (SFA) intake and coronary heart disease (CHD) risk, although in the latter case these observations were attenuated and in some cases became non-significant after adjusting for other dietary factors. Data from large-scale primary and secondary intervention studies support a positive relationship between CHD and SFA. The majority of data available were derived from male subjects, and if female subjects were included, few studies assessed the effect of gender on responsiveness. Recent evidence has emerged suggesting that females respond differently to diet with respect to CHD progression. This review discusses controlled clinical intervention studies that included data for both genders and their responses to dietary fat perturbations and lipoprotein profiles. The scope was limited for the most part to reports that included identifiers in the title or abstract that indicated data for female and male subjects were reported separately, although a statistical comparison between the genders may not have been reported. Overall, whether the studies assessed the effect of the ratio of SFA to monounsaturated fatty acids (MUFA), SFA to polyunsaturated fatty acids (PUFA), MUFA to PUFA, individual SFA, or SFA to trans fatty acids, female and male subjects responded similarly, and when differences were identified there was no consistent pattern.

Cardiovascular Diseases↗