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PubMed1979

Mass spectrometric analysis of deuterium dual labeled blood lipids.

A gas chromatography selected ion monitoring mass spectrometer technique was developed to analyze deuterium dual labeled blood lipid samples from a human feeding experiment. In the metabolism experiment, described elsewhere. [2H2] labeled cis and [2H4] labeled trans fatty acids were fed to a human sujbect as a single pulse in order to determine whether the human body differentiates between cis and trans fatty acids in the diet. The analytical method described here was developed to accurately measure the ratio of [2H2]methyl oleate to [2H4]methyl elaidate in the presence of large amounts of [2H0] methyl oleate in samples derived from separated fractions of blood lipids. The technique is different from most selected ion monitoring methods in that the internal standard was fed to the subject along with the experimental material; the samples contained large amounts of unlabeled material chemically identical to the labeled material and the ratio of [2H2] to [2H4] fatty esters was of principal interest rather than the absolute value. Nine standards were analyzed eight or more times to form a basis for statistical evaluation of the method. Analysis of the plasma phosphatidyl ethanolamine fraction from the metabolic experiment is given as an example.

Analog-Digital Conversion↗
PubMed1985

Stimulation of the Ca2+-dependent polymerization of synexin by cis-unsaturated fatty acids.

The influence of fatty acids on the polymerization of synexin was studied by monitoring light scattered from solutions of purified synexin. Cis-unsaturated fatty acids such as arachidonate or oleate stimulated synexin polymerization at sub-micromolar concentrations, while saturated fatty acids, a trans unsaturated fatty acid or a fatty acid methyl ester had little effect. The polymerization of synexin occurred at lower concentrations of Ca2+ in the presence of the fatty acids than in the absence of fatty acids. Therefore, Ca2+ and free fatty acids may act as co-regulators of synexin action in stimulated secretory cells.

Animals↗
PubMed2005

[Management of behavioral risk factors for cardiovascular disease (CVD)].

Changes in many patterns of individual risk behaviors (unhealthy diet, smoking, sedentary lifestyle) are necessary in a large majority of patients with established CVD or at high risk of CVD. Make healthy food choices. Energy intake must be adjusted to maintain ideal body weight. Eating from each major food group will ensure dietary balance. The consumption of fruits and vegetables, whole grain cereals and bread, low fat dairy products, fish and lean meat should be encouraged. Oily fish and omega-3-fatty acids are specially recommended. Saturated and trans fatty acids should be replaced with MUFA's or PUFA's of vegetable and seafood origins. Totalfat intake should account for no more than 30% of energy intake, and intake of saturated fats should not exceed a third of total fat intake. The intake of cholesterol should be less than 300 mg/day. Stop smoking tobacco. All smokers should be professionally encouraged to permanently stop smoking all forms of tobacco. Increase physical activity. A lack of regular physical activity may contribute to the early onset and progression of Cardiovascular Disease. Regular physical activity and the maintenance of physical fitness is beneficial in all age groups and should be promoted as an integral part of cardiovascular prevention. Healthy people should be advised to choose enjoyable activities, which fit into their daily routine, preferably 30-40 min, 4-5 times weekly at Borg 13 or at 60-75% of the average maximum heart rate. For patients with established CVD, advice must be based on a comprehensive clinical judgement including the results of an exercise test.

Cardiovascular Diseases↗
PubMed2000

Dietary stearic acid reduces cholesterol absorption and increases endogenous cholesterol excretion in hamsters fed cereal-based diets.

The observation that dietary stearic acid does not raise plasma cholesterol concentration is well documented, although the regulating mechanisms are not completely understood. Therefore, we examined the effect of dietary stearic acid on cholesterol absorption and sterol balance using male Syrian hamsters fed modified NIH-07 cereal-based diets selectively enriched in palmitic acid (16:0), stearic acid (18:0), trans fatty acid (18:1t), cis oleic acid (18:1c) or linoleic acid (18:2). All diets contained 17 g/100 g total fat and 0.05 g/100 g cholesterol; the five fat blends were enriched 30% with the fatty acid of interest above a constant fatty acid background. Cholesterol absorption efficiency was 50-55% in all treatment groups except for the 18:0 group, in which cholesterol absorption was significantly reduced to 21%. Plasma total cholesterol concentration was significantly lower in the 18:0 group compared to the 16:0 group. Fecal neutral steroid excretion was significantly greater in hamsters fed the high 18:0 diet compared to the other treatment groups. After accounting for unabsorbed dietary cholesterol, endogenous cholesterol excretion was about 100% higher in the 18:0 group. Consequently, the calculated rate of whole body cholesterol synthesis was significantly increased by dietary 18:0. Bile acid excretion accounted for only 12-20% of total sterol output by the hamsters in this study. Thus, the data suggest that reduced plasma cholesterol concentration in hamsters fed high 18:0 diets may be influenced by reduced cholesterol absorption and increased excretion of endogenous cholesterol.

Analysis of Variance↗
PubMed2005

Inter-esterified palm products as alternatives to hydrogenation.

Inter-esterification is one of the processes used to modify the physico-chemical characteristics of oils and fats. Inter-esterification is an acyl-rearrangement reaction on the glycerol molecule. On the other hand, hydrogenation involves addition of hydrogen to the double bonds of unsaturated fatty acids. Due to health implications of trans fatty acids, which are formed during hydrogenation, the industry needs to find alternatives to hydrogenated fats. This paper discusses some applications of inter-esterified fats, with particular reference to inter-esterified palm products, as alternatives to hydrogenation. Some physico-chemical properties of inter-esterified fats used in shortenings are discussed. With inter-esterification, more palm stearin can be incorporated in vanaspati. For confectionary fats and infant formulations, enzymatic inter-esterification has been employed.

Chemical Phenomena↗
PubMed1997

Intake of fatty acids and risk of coronary heart disease in a cohort of Finnish men. The Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study.

The relation of intakes of specific fatty acids and the risk of coronary heart disease was examined in a cohort of 21,930 smoking men aged 50-69 years who were initially free of diagnosed cardiovascular disease. All men participated in the Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study and completed a detailed and validated dietary questionnaire at baseline. After 6.1 years of follow-up from 1985-1988, the authors documented 1,399 major coronary events and 635 coronary deaths. After controlling for age, supplement group, several coronary risk factors, total energy, and fiber intake, the authors observed a significant positive association between the intake of trans-fatty acids and the risk of coronary death. For men in the top quintile of trans-fatty acid intake (median = 6.2 g/day), the multivariate relative risk of coronary death was 1.39 (95% confidence interval (CI) 1.09-1.78) (p for trend = 0.004) as compared with men in the lowest quintile of intake (median = 1.3 g/day). The intake of omega-3 fatty acids from fish was also directly related to the risk of coronary death in the multivariate model adjusting also for trans-saturated and cis-monounsaturated fatty acids (relative risk (RR) = 1.30, 95% CI 1.01-1.67) (p for trend = 0.06 for men in the highest quintile of intake compared with the lowest). There was no association between intakes of saturated or cis-monounsaturated fatty acids, linoleic or linolenic acid, or dietary cholesterol and the risk of coronary deaths. All the associations were similar but somewhat weaker for all major coronary events.

Aged↗
PubMed2005

Lower fetal status of docosahexaenoic acid, arachidonic acid and essential fatty acids is associated with less favorable neonatal neurological condition.

Long-chain polyunsaturated fatty acids, notably arachidonic (AA) and docosahexaenoic (DHA) acids are abundant in brain and may be conditionally essential in fetal life. We investigated umbilical artery (UA) and vein (UV) fatty acid compositions and early neonatal neurological condition in 317 term infants. Neurological condition was summarized as a clinical classification and a 'neurological optimality score' (NOS). Neurologically abnormal infants (n=27) had lower UV DHA and essential fatty acid (EFA) status. NOS correlated positively with AA (UV), and EFA (UV) and DHA status (UV and UA) and negatively with 18:2omega6 and omega9 (UV), and 20:3omega9, omega7 and C18 trans fatty acids (UV and UA). UV DHA, AA, saturated fatty acids, gestational age and obstetrical optimality score explained 16.2% of the NOS variance. Early postnatal neurological condition seems negatively influenced by lower fetal DHA, AA and EFA status. C18 trans fatty acids and 18:2omega6 may exert negative effects by impairment of LCP status.

Arachidonic Acid↗
PubMed1992

A comparative study of micronucleus frequency in peripheral blood lymphocytes of human subjects given dietary cis, trans and saturated fat.

The micronucleus test using peripheral blood lymphocytes has been used to study the clastogenic effects of saturated, cis or trans fatty acids in human volunteers. Consumption of diets rich in either saturated fats (palmitic acid), monounsaturated cis fats (oleic acid) or monounsaturated trans fats (elaidic acid) for 3 wk had no effect on either the number of micronuclei or the frequency of micronucleated cells in lymphocytes in culture. This study adds to the accumulating body of evidence to suggest that dietary intake of trans fatty acids is not especially linked to genetic damage.

Adult↗
PubMed1987

Fatty acid patterns in triglycerides, diglycerides, free fatty acids, cholesteryl esters and phosphatidylcholine in serum from vegetarians and non-vegetarians.

The differences in the fatty acid spectra of serum samples obtained from vegetarians (62 females, 40 males) and non-vegetarians (70 females, 38 males) were evaluated in a matched-pair study design. This study population made it possible to examine 48 female and 31 male pairs whose age difference did not exceed 3 years. The pairs were further matched by education, social status and health-consciousness. The fatty acid pattern of whole serum total lipids and HDL total lipids were determined by GLC. In particular linoleic, linolenic, oleic and docosahexaenoic acid reveal statistically significant differences due to different nutritional habits. A subsample (n = 20) of sera from the 2 groups was investigated by separation of lipid classes by TLC and GLC on a SP 2,340 fused-silica capillary column in order to separate cis-trans fatty acids additionally. This part of the study gives detailed information concerning the fatty acid composition of cholesteryl esters, triglycerides, diglycerides, free fatty acids and phosphatidylcholine. In all those fractions the fatty acid profiles reflect the dietary consumption of lipids. Palmitoleic, vaccenic and docosahexaenoic acid as markers of omnivorous nutrition reach levels of 5, 5 and 3% respectively in non-vegetarians, while they remain remarkably lower in vegetarians. The most prominent difference is the higher amount of linoleic acid in all lipid classes of vegetarian serum samples. The highest amount of trans fatty acids (up to 3%) was detected in di- and triglycerides.

Adolescent↗
PubMed2005

Hypertension prevention: from nutrients to (fortified) foods to dietary patterns. Focus on fatty acids.

Diet affects significantly the incidence and severity of cardiovascular diseases and fatty acid intake, in its qualitative as well as quantitative aspects, and influences several risk factors including cholesterol (total, LDL and HDL), triglycerides, platelet aggregation and blood pressure, as evidenced in the 2001 WHO report. This review focuses on the qualitative concern of lipid intake, the various classes of fatty acids of the lipid fraction of the diet, saturated, monounsaturated and polyunsaturated, and their effects on blood pressure. Saturated fat have a bad file and several experimental studies in the rat showed a progressive increase in blood pressure in response to a highly saturated diet. Moreover, a highly saturated diet during gestation led to offspring which, when adults, presented a gender-related hypertension. The mechanism of this effect may be related to the polyunsaturated/saturated ratio (p/s). During the past 20 years, trans fatty acids have been suspected of deleterious health effects, but the investigations have shown that these fatty acids display a biological behaviour close to that of saturated fatty acids (SFA). Moreover, epidemiological investigations did not confirm the relationship between trans fatty acids and cardiovascular pathology. Polyunsaturated fatty acids have been shown to exert a positive action on hypertension. This effect could be attributed to the alteration of the p/s, but mainly to the omega3 polyunsaturated fatty acids (PUFAs). The comparison of several animal models led to the conclusion that long-chain omega3 PUFAs (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) can prevent the increase in blood pressure and reduce established hypertension, but the efficient dose remains an object of discussion. Moreover, the two long-chain omega3 PUFAs, EPA and DHA, display specific effects, which vary with the aetiology of hypertension, because their mechanism of action is different. DHA acts on both blood pressure and heart function (heart rate and ECG) and interferes with the adrenergic function. Conversely, EPA, which is not incorporated in cardiac phospholipids, has no effect on the heart and its mechanism of action is largely unknown. Although it is accepted by the scientific community that the intake of EPA and DHA needs to be increased, we will have to discover new ways to do it, since marine products are the main source of these fatty acids, and this source is not inexhaustible.

Blood Pressure↗
PubMed1979

The effects of trans trans methyl linoleate on the concentration of prostaglandins and their precursors in rat.

Four groups of weanling male rats were fed a diet containing hydrogenated coconut oil (Treatment A); 9-trans, 12-trans linoleate (trans linoleate, (Treatment B); an equal mixture of 9-cis, 12-cis linoleate (cis linoleate) and trans linoleate (Treatment C); and cis linoleate (Treatment D); respectively for 12 weeks. The level of dietary fat was 11% of calories. Only trace amount of eicosatrienoic acid (C20:3w6) was detected in tissues, (liver, platelets) of rats in Treatments A and B. The level of C20:3w6 in platelet lipids of Treatments C and D was 0.1 and 0.33% respectively. The level of arachidonic acid in rats on Treatments A, B, C and D was 2.0, 1.4, 14.1 and 17.6% for platelet lipids, respectively. The serum levels of prostaglandin PGE1 for Treatments A, B, C and D were 1.10 +/- 0.24, 0.22 +/- 0.02, 3.51 +/- 0.58 and 5.69 +/- 0.59 ng/ml, respectively and 2.19 +/- 0.85, 0.15 +/- 0.03, 11.64 +/- 2.63 and 24.89 +/- 4.35 ng/ml for PGE2, respectively. Thus feeding trans linoleate to rats apparently caused decreased biosynthesis of PGs resulting from decreased levels of precursor acids. This was apparently due to the inhibition of conversion of cis linoleate to longer chain polyunsaturated fatty acids. The results indicate that the availability of precursor acids is one limiting factor in PG biosynthesis in rats, and small differences in the level of precursor acids, affected by dietary trans fatty acids may cause large variations in amounts of PGs synthesized.

Animals↗
PubMed1980

Metabolism and positional distribution of isomers of 18-carbon dienoic fatty acids containing trans and cis double bonds by developing rat brain.

In addition to dietary linoleic acid (cis,cis-18:2), trans isomers of 18:2 may be ingested as minor components of partially hydrogenated oils. Developing rat brain has significant capacity for conversion of cis,cis-18:2 to more abundant polyenes by desaturation and elongation, but less is known about trans dienes. We have shown that incorporation of 1-14C-labeled cis,cis-,cis,trans-, and trans,trans-18:2 into brain lipids of 10-day-old rats is significant but that metabolism of the isomers between 0.2 and 72 h after intracerebral injection differs markedly. Incorporation of trans,trans-18:2 into phosphoglyceride and triacylglycerol was slower than that for cis,cis diene. Oxidation of all isomers occurred with formation of similar quantities of labeled cholesterol and palmitate. However, metabolism of trans dienes differed in two important respects: (i) desaturation and elongation of trans-containing diene was much less (less than 5 versus greater than 30% for cis,cis-18:2 after 6 h); (ii) trans,trans-18:2 and palmitate appeared to be preferentially esterified to the 1 position, whereas cis,cis-18:2 and its products were mainly in the 2 position of choline and ethanolamine phosphoglycerides. Thus, developing brain does not appear to ensure exclusion of trans dienes from membrane lipids; however, conversion by desaturation and elongation and selectivity for position of acylation differ markedly for the cis- and trans-containing dienoic isomers.

Animals↗
PubMed2002

Bioconversion of vaccenic acid to conjugated linoleic acid in humans.

BACKGROUND: Vaccenic acid (11-trans octadecenoic acid; VA), a major trans fatty acid in the fat of ruminants, is produced in the rumen and converted in tissues to rumenic acid (9-cis, 11-trans octadecenoic acid; RA), an isomer of conjugated linoleic acid, by Delta(9)-desaturase. There are indications that this conversion also occurs in humans. OBJECTIVE: The aim of this controlled intervention was to study the conversion of VA to RA in humans after consumption of diets with increasing amounts of VA. DESIGN: Thirty healthy subjects consumed a baseline diet rich in oleic acid for 2 wk. The subjects were then divided into 3 groups (n = 10 per group) and provided a diet containing 1.5, 3.0, or 4.5 g VA/d for 9 d. All diets contained equal amounts of macronutrients and differed only in their fatty acid compositions. The fats were mixed into conventional foods, and nearly all food was provided during the study. RESULTS: The proportion of VA in serum total fatty acids increased 94%, 307%, and 620% above baseline with the 1.5-, 3.0-, and 4.5-g diets, respectively. This was associated with a linear increase in the proportion of RA. The conversion rate was 19% on average, with significant interindividual differences with all 3 intakes of VA. The urinary excretion of 8-iso-prostaglandin F(2alpha) increased in all groups (P < 0.001). CONCLUSIONS: The results quantify the desaturation of VA to RA in humans. Conversion is likely to contribute significantly to the amount of RA available to the body, and dietary intakes of VA should thus be taken into account when predicting RA status.

Adult↗
PubMed2003

A divergent synthesis of [1-14C]-mono-E isomers of fatty acids.

A convenient synthesis of [1-14C]-mono-trans fatty acid using olefin inversion as a key-step is described. This methodology allows for a facile synthesis of [1-14C]-labelled mono-trans analogues of oleic, linoleic and linolenic acids. As an example, only eleven steps were necessary to obtain the [1-14C]-mono-E isomers of linolenic acid from its commercial all-Z form. In the first step, Barton's decarboxylation procedure yielded a bromo intermediate. Epoxidation of this compound resulted in the formation of three monoepoxides, which could be separated by HPLC. After identification by 1H NMR and MS, the pure monoepoxides were then subjected to inversion consisting of a stereospecific deoxygenation followed by a beta-elimination step. Finally, the labelling was introduced by substitution of the bromine by a [14C]-cyano group followed by hydrolysis.

Chromatography, High Pressure Liquid↗
PubMed2002

Isomerization of stable isotopically labeled elaidic acid to cis and trans monoenes by ruminal microbes.

A previous study showed that oleic acid was converted by mixed ruminal microbes to stearic acid and also converted to a multitude of trans octadecenoic acid isomers. This study traced the metabolism of one of these trans C18:1 isomers upon its incubation with mixed ruminal microbes. Unlabeled and labeled (18-[13C]trans-9 C18:1) elaidic acid were each added to four in vitro batch cultures with three cultures inoculated with mixed ruminal bacteria and one uninoculated culture. Samples were taken at 0, 12, 24, and 48 h and analyzed for 13C enrichment in component fatty acids by gas chromatography-mass spectrometry. At 0 h of incubation, enrichment was detected only in elaidic acid. By 48 h of incubation, 13C enrichment was 18% (P < 0.01) for stearic acid, 7% to 30% (P < 0.01) for all trans C18:1 isomers having double bonds between carbons six through 16, and 5% to 10% for cis-9 and cis-11 monoenes. After 48 h, 13C enrichment in the uninoculated cultures was only detected in the added elaidic acid. This study shows trans fatty acids exposed to active ruminal cultures are converted to stearic acid but also undergo enzymic isomerization yielding a multitude of positional and geometric isomers.

Animals↗
PubMed1994

Confirmation by gas chromatography/mass spectrometry of two unusual trans-3-monoethylenic fatty acids from the Nova Scotian seaweeds Palmaria palmata and Chondrus crispus.

The structures of two unusual fatty acids, the known trans-3-hexadecenoic acid and a novel trans-3-tetradecenoic acid, both isolated from the Nova Scotian seaweeds Palmaria palmata and Chondrus crispus, were positively identified. After the extraction of the total fatty acids by saponification, followed by methylation, the monoenoic trans fractions were isolated by thin-layer chromatography on silica gel impregnated with silver nitrate. The monoenoic trans fractions were derivatized with 2-amino-2-methyl-propanol prior to analysis by gas chromatography/mass spectrometry. The mass spectra showed prominent [M + 1]+ ions but lacked the 12 amu interval useful for identifying the double bond position. Hence, alternative diagnostic peaks were used to confirm the position of the double bond in these two fatty acids. As the trans-3-hexadecenoic acid is found in the photosynthetic tissue of all plants, it may also be present in ruminant fats and, presumably, in human adipose tissue.

Buffers↗
PubMed2001

Partially hydrogenated soybean oil reduces postprandial t-PA activity compared with palm oil.

The effects of dietary trans fatty acids on fasting and diurnal variation in hemostatic variables are not known. This study compares the effects of three diets with three different margarines, one based on palm oil (PALM-diet), one based on partially hydrogenated soybean oil (PHSO, TRANS-diet) and one with a high content of polyunsaturated fatty acids (PUFA-diet) on diurnal postprandial hemostatic variables. A strictly controlled dietary Latin square study was performed and nine young female participants consumed each of the diets for 17 days in a random order. The sum of the cholesterol-increasing fatty acids (C12:0, C14:0, C16:0) was 36.3% of total fatty acids in the PALM-diet, the same as the sum of saturated-(C12:0, C14:0, C16:0) (12.5%) and trans fatty acids (23.1%) in the TRANS-diet. The sum of C12:0, C14:0 and C16:0 was 20.7% in the PUFA-diet. The amount of fat made up 30-31% of energy in all diets. Nine participants completed the study. The diurnal postprandial state level of tissue plasminogen activator (t-PA) activity was significantly decreased on the TRANS-diet compared with the PALM-diet. t-PA activity was also decreased on the PUFA-diet compared with PALM-diet but the difference was below statistical significance (P=0.07, Bonferonni adjusted). There were no significant differences in either fasting levels or in circadian variation of t-PA antigen, PAI-1 activity, PAI-antigen, factor VII coagulant activity or fibrinogen between the three diets. Our results indicate that dietary trans fatty acids from PHSO has an unfavourable effect on postprandial t-PA activity and thus possibly on the fibrinolytic system compared with palm oil.

Adult↗
PubMed1983

Alteration of rat heart sarcolemma lipid composition by dietary elaidic acid.

Male weanling rats were fed a semisynthetic diet containing 5% of either elaidic acid or oleic acid for 4 weeks. The heart sarcolemma were isolated and examined for purity by using marker enzymes. The sarcolemma preparations were enriched in phosphodiesterase I, 5'-nucleotidase and p-nitrophenyl phosphatase as compared with the heart homogenates. Succinic dehydrogenase activity was not detected in these preparations. The lipids of sarcolemma fractions from animals fed the trans fatty acids were enriched with the fatty acid fed. Most of this incorporation was found to be associated with the two major phospholipids, phosphatidylcholine and phosphatidylethanolamine. The incorporation of elaidic acid into the membranes resulted in an increase in membrane cholesterol without affecting either membrane phospholipid content or profile. The alterations induced in the lipid composition of heart sarcolemma by feeding this dietary trans fatty acid suggest some functional alterations in these membranes.

Animals↗