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PubMed2006

Dietary supplementation with 11trans- and 12trans-18:1 and oxidative stress in humans.

BACKGROUND: High consumption of trans fat has been associated with high oxidative stress in humans, which could increase the risk of the development or acceleration of several diseases, such as atherosclerosis, cancer, and type 2 diabetes. OBJECTIVE: Several urinary and blood biomarkers of oxidative stress [8-iso-prostaglandin-F(2alpha) (PGF(2alpha)), 15-keto-dihydro-PGF(2alpha), and 7,8-dihydro-8-oxo-2'-deoxy-guanosine in urine and alpha-,beta-,gamma-,delta-tocopherol, and retinol in plasma] were monitored to evaluate the oxidative stress induced by dietary supplementation of 11trans- and 12trans-18:1 isomers in humans during a 6-wk intervention. DESIGN: After a 14-d adaptation period free of trans fatty acid supplementation (baseline), the test group (n = 12) received 3.0 g 11trans-18:1/d and 3.0 g 12trans-18:1/d (Sigma 6.0 g/d), and the control group (n = 12) consumed a control oil free of trans fatty acids and conjugated linoleic acids for 6 wk. RESULTS: The postintervention concentration of urinary 8-iso-PGF(2alpha) (free radical-induced lipid peroxidation) in the test group was significantly higher than baseline and significantly higher than that observed in the control group. The concentrations of 15-keto-dihydro-PGF(2alpha) (cyclooxygenase-mediated inflammatory response indicator) and 7,8-dihydro-8-oxo-2'-deoxy-guanosine (oxidative DNA damage) were not affected by the 11trans- and 12trans-18:1 supplementation. CONCLUSIONS: Although an increase in urinary 8-iso-PGF(2alpha) was observed and the effects of prolonged high (ie, >5.0 g/d) consumption of trans fat could be relevant to the development of disease, the mean intakes of 11trans- and 12trans-18:1 in Europeans are estimated to be significantly below the amounts administered in this study (ie, 6.0 g/d); such low intakes could minimize the possible risk of detrimental effects on human health.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2001

Isomerization increases the postprandial oxidation of linoleic acid but not alpha-linolenic acid in men.

Human lipid intake contains various amounts of trans fatty acids. Refined vegetable and frying oils, rich in linoleic acid and/or alpha-linolenic acid, are the main dietary sources of trans-18:2 and trans-18:3 fatty acids. The aim of the present study was to compare the oxidation of linoleic acid, alpha-linolenic acid, and their major trans isomers in human volunteers. For that purpose, TG, each containing two molecules of [1-(13)C]linoleic acid, alpha-[1-(13)C]linolenic acid, [1-(13)C]-9cis,12trans-18:2, or [1-(13)C]-9cis,12cis,15trans-18:3, were synthesized. Eight healthy young men ingested labeled TG mixed with 30 g of olive oil. Total CO(2) production and (13)CO(2) excretion were determined over 48 h. The pattern of oxidation was similar for the four fatty acids, with a peak at 8 h and a return to baseline at 24 h. Cumulative oxidation over 8 h of linoleic acid, 9cis,12trans-18:2, alpha-linolenic acid, and 9cis,12cis,15trans-18:3 were, respectively, 14.0 +/- 4.1%, 24.7 +/- 6.7%, 23.6 +/- 3.3%, and 23.4 +/- 3.7% of the oral load, showing that isomerization increases the postprandial oxidation of linoleic acid but not alpha-linolenic acid in men.

Adult↗
PubMed2002

Arachidonate geometrical isomers generated by thiyl radicals: the relationship with trans lipids detected in biological samples.

The presence of trans fatty acids in mammalians is attributed to exogenous sources; nevertheless, trans isomers could be easily formed by free radical-catalyzed isomerization processes in vivo. The isomerization of methyl arachidonate (all-cis isomer) catalyzed by thiyl radical is proposed as a methodology applicable in biochemical laboratories, which produces mono- and di-trans isomers. Carbon-13 nuclear magnetic resonance spectroscopy shows that the carbon atom in position 15 is characteristic for each mono- and di-trans isomer. Antioxidants, such as alpha-tocopherol and all-trans-retinol acetate, inhibited the isomerization process. Trans phospholipids are formed in erythrocyte membranes by exposing blood to gamma-irradiation in the presence of thiols, which is in contradiction with the known role of these compounds as radioprotectors. Trans isomers are also analyzed in tissues harvested from breast cancer patients and compared to the adipose breast tissue taken a few centimeters from the edge of the tumor from the same patient. This work is generally aimed at contributing to the debate on trans fatty acids and stimulating a reconsideration of the current view on the exclusive presence of cis double bonds in cell membranes by studying radical processes that could affect or protect this natural configuration.

Adipose Tissue↗
PubMed1998

Positional analysis of triacylglycerols from bovine adipose tissue lipids varying in degree of unsaturation.

The objective of this study was to demonstrate that changing the fatty acid composition of bovine adipose tissue concurrently changed (i) proportions of triacylglycerol species, (ii) fatty acid composition of triacylglycerol species, and (iii) positional distribution of the component fatty acids of the triacylglycerol species. To achieve this, we took advantage of adipose tissue lipids, from cattle fed in Australia and Japan, that varied widely in fatty acid composition and melting points. Treatment groups produced in Australia were cattle fed: a cornbased diet (MUFA1); a grain-based diet containing whole cottonseed (SFA); a grain-based diet containing protected cottonseed oil (PUFA); and a grain-based diet that resulted in high contents of trans fatty acids (TFA). Treatment groups produced in Japan (MUFA2 and MUFA3) were diets of unknown composition fed for over 300 d. The MUFA1, MUFA2, and MUFA3 samples all were rich in monounsaturated fatty acids, varying only in the proportions of the individual monounsaturates. The SFA, PUFA, and TFA samples had relatively high concentrations of stearic acid (18:0), PUFA, and TFA, respectively. Slip points (indicative of melting points) were 45.1, 41.5, 38.5, 30.7, 28.4, and 22.8 degrees C, for the SFA, TFA, PUFA, MUFA1, MUFA2, and MUFA3 groups, respectively (P < 0.05). Triacylglycerols were separated by high-performance liquid chromatography on a silver nitrate-impregnated column into sn-1,2,3-saturated fatty acid triacylglycerol (SSS); [triacylglycerols containing two saturated acids and one trans-monounsaturated fatty acid (SMMt sn-positions unknown)]; sn-1-saturated, 2-monounsaturated, 3-saturated triacylglycerol (SMS); sn-1-saturated, 2-monounsaturated 3-trans-monounsaturated triacylglycerol (SMMt); sn-1-saturated, 2,3-monounsaturated fatty acid triacylglycerol (SMM); sn-1-saturated, 2-polyunsaturated, 3-trans-monounsaturated triacylglycerol; sn-1,2,3-monounsaturated fatty acid triacylglycerol (MMM); and sn-1-saturated, 2-polyunsaturated, 3-monounsaturated triacylglycerol. Fatty acid methyl esters of each triacylglycerol species also were determined, and further analysis indicated sn-2, and sn-1/3 positions. As the percentage oleic acid increased in the total lipid extract, the proportions of SMM and MMM increased (e.g., from 31.4 and 2.4% in the SFA group to 55.4 and 17.8% in the MUFA3 group). The elevated 18:0 in the SFA group (26%) was reflected in increased percentages of SSS and SSM, and caused an increase in the proportion of 18:0 in all triacylglycerol species relative to the other treatment groups. The percentage of 18:0 in the sn-1/3 positions was elevated markedly in the SMS fraction of the SFA group (to 44%); this would account for the high melting point of the fat of these animals. We conclude that long-term feeding of cattle is sufficient to produce significant alterations in fatty acid composition in bovine adipose tissue. Alterations in the fatty acid composition of bovine adipose tissue changed both the distribution and the composition of the triacylglycerol species, which, in turn, accounted for marked differences in melting points among treatment groups.

Adipose Tissue↗
PubMed1986

Use of published analyses of food items to determine dietary trans octadecenoic acid.

To estimate the dietary levels of trans octadecenoic acid (18:1t) in the diets of eight healthy white adolescent girls, diet records were obtained for a 7-day period. Published trans fatty acid values in foods were used to calculate the trans octadecenoic acid present in the diets. The usefulness of this method was tested by comparing the estimated values with values obtained by chemical analysis of diets collected by the duplicate portion technique from the same subjects over the same period of time. There was no significant difference in the values for the trans octadecenoic acid content of the 54 diets used in this study whether the values were calculated from the diet records or determined by chemical analysis. Dietary trans octadecenoic acid averaged 5.3% of total fatty acids by both methods. The mean trans octadecenoic acid in the daily diet was 2.8 gm as calculated from the diet records and 2.6 gm according to actual analysis. Those values were not significantly different. The present study demonstrated that the trans octadecenoic acid content of the diets of a group of adolescent girls can be estimated from diet records using previously published values for individual food items.

Adolescent↗
PubMed2001

Analysis of fatty acid isomers in ruminant tissues by silver thin layer chromatography followed by gas chromatography.

A method for the analysis of trans fatty acids is described in this paper. Separation of trans isomers from the corresponding cis was based on the different facility with which the double bonds in the alkyl chains of both types of fatty acids form polar complexes with silver, and it was carried out by Thin Layer Chromatography (TLC), using silver nitrate impregnated plates. Further separation, identification and quantification of the individual C18:1 isomers, analysed as methyl esters, was carried out by Gas Chromatography (GC). The determination of the content of the isomer t11-C18:1 in ruminant tissues can contribute to try to elucidate the metabolic pathway formation of conjugated linoleic acid (CLA), shown as a fatty acid of beneficial health effects. Furthermore, the analysis of trans fatty acids in other dietary foods seems to be interesting due to their influence on the modification of the serum lipids profile and the role of this type of compounds in human health.

Animals↗
PubMed1995

Effects of randomization of partially hydrogenated corn oil on fatty acid and cholesterol absorption, and tissue lipid levels in rats.

Randomization of partially hydrogenated corn oil containing approximately 45% of trans octadecenoic acid only slightly, but not significantly, increased the lymphatic fatty acid absorption in rats. No effect of randomization was observed on cholesterol absorption. When rats were fed these fats at the 8.8% level (with 1.2% safflower oil) for three weeks, the concentrations of serum cholesterol, and serum and liver phospholipid were significantly higher in randomized fat than in control fat, which was composed of 9% high-oleic safflower oil and 1% palm oil. Liver cholesterol tended to be higher in randomized fat. In contrast, nonrandomized fat was not hyperlipidemic compared to control fat. Although the fatty acid composition of liver phospholipids suggested a possible interference of trans fatty acid with the metabolism of linoleic acid to arachidonic acid, there was no effect of randomization. In the two hydrogenated fat groups, trans octadecenoic acid was incorporated and distributed similarly in adipose tissue triacylglycerol. These observations indicated that randomization of partially hydrogenated fat is not beneficial to various lipid parameters in rats.

Absorption↗
PubMed1996

Trans, n-3, and n-6 fatty acids in Canadian human milk.

The presence of trans fatty acids in human milk may be a concern because of their possible adverse nutritional and physiological effects on the recipient infant. The mother's diet is the source of human milk trans fatty acids, and since these fatty acids are prevalent in many common foods of the Canadian diet, the trans fatty acid content and the fatty acid composition of Canadian human milk were measured by gas-liquid chromatography coupled with silver nitrate-thin layer chromatography. In samples obtained from 198 lactating mothers across Canada, the average percentage of total trans (sum of t18:1, t18:2, and t18:3) was 7.2% of breast milk fatty acids with a range of 0.1-17.2%. Analysis of t18:1 isomer distribution indicated that partially hydrogenated vegetable oils are the major source of these trans fatty acids in human milk, whereas contribution from dairy products appeared to be relatively minor. Linoleic and alpha-linolenic acid levels were inversely related to the total trans fatty acids, indicating that the elevation of trans fatty acids in Canadian human milk is at the expense of n-3 and n-6 essential fatty acids. Levels of arachidonic and docosahexaenoic acids did not correlate with their parent fatty acids, indicating that it might be difficult to elevate the levels of n-6 and n-3 c20-22 polyunsaturated fatty acids in breast milk by increasing levels of linoleic and alpha-linolenic acids in the mother's diet.

Canada↗
PubMed2006

Effects of butter high in ruminant trans and monounsaturated fatty acids on lipoproteins, incorporation of fatty acids into lipid classes, plasma C-reactive protein, oxidative stress, hemostatic variables, and insulin in healthy young men.

BACKGROUND: Evidence suggests that ruminant trans fatty acids (FAs), such as vaccenic acid, do not increase the risk of ischemic heart disease (IHD). However, the effects of ruminant trans FAs on risk markers of IHD have been poorly investigated. OBJECTIVE: The objective was to investigate the effect of butter with a naturally high content of vaccenic acid and a concomitantly higher content of monounsaturated FAs on classic and novel risk markers of IHD. DESIGN: In a double-blind, randomized, 5-wk, parallel intervention study, 42 healthy young men were given 115 g fat/d from test butter that was high in vaccenic acid (3.6 g vaccenic acid/d) or a control butter with a low content of vaccenic acid. Blood and urine samples were collected before and after the intervention. RESULTS: The intake of the vaccenic acid-rich diet resulted in 6% and 9% lower total cholesterol and plasma HDL-cholesterol concentrations, respectively, than did the intake of the control diet (P = 0.05 and 0.002, respectively), whereas the ratio of total to HDL cholesterol did not differ significantly between the groups. The FA composition of lipid classes reflected the FAs' proportion of the test butter. No other differences were observed. CONCLUSIONS: Butter high in ruminant trans and monounsaturated FAs resulted in significantly lower total and HDL cholesterol than did the control butter with higher amounts of saturated FAs. It may be that the differences were due to the greater content of monounsaturated FAs and the lesser content of saturated FAs in the butter rich in ruminant trans FAs, rather than to the content of vaccenic acid per se.

Adult↗
PubMed1997

Margarine intake and subsequent coronary heart disease in men.

Margarine is a major source of trans fatty acids, the intake of which has risen since the early 20th century. Some data indicate that consumption of trans fatty acids increases the risk of coronary heart disease (CHD). In 1966-1969, 832 men from the Framingham Study, age 45-64 years and free of CHD, were administered a single 24-hour dietary recall, from which we estimated total daily margarine intake. We calculated CHD cumulative incidence rates and, using proportional hazards regression, CHD incidence rate ratios over 21 years of follow-up. Mean energy intake was 2,619 kcal; mean margarine intake was 1.8 (range 0-12) tsp per day. There were 267 incident cases of CHD. Age-adjusted CHD cumulative incidence rose over categories of margarine intake, but the increased risk was apparent only in the second half of the follow-up period. Adjusted for age and energy intake, the risk ratio for CHD for each increment of 1 teaspoon per day of margarine was 0.98 [95% confidence interval (CI) = 0.91-1.05] for the first 10 years of follow-up and 1.10 (95% CI = 1.04-1.17) for follow-up years 11-21. Adjustment for total fat intake and for cigarette smoking, glucose intolerance, left ventricular hypertrophy, body mass index, blood pressure, physical activity, and alcohol intake did not materially change the results. Butter intake did not predict CHD incidence. These data offer modest support to the hypothesis that margarine intake increases the risk of coronary heart disease.

Age Distribution↗
PubMed1999

Effect of dietary sesamin on metabolic fate of an exogenous linolelaidic acid in perfused rat liver.

To estimate the relative significance of exogenous and endogenous fatty acid substrates in decreasing hepatic triacylglycerol secretion after sesamin feeding, livers from rats fed diets supplemented with and without sesamin (sesamin: episesamin, 1:1, w/w) were perfused in the presence and absence of an exogenous di-trans isomer of linoleic acid (linolelaidic acid, trans,trans-9,12-octadecadienoic acid). Both exogenous trans fatty acid and dietary sesamin, as compared with respective controls, resulted in a marked increase in hepatic ketogenesis; however, the beta-hydroxybutyrate to acetoacetate ratio was elevated by exogenous fatty acid and decreased by dietary sesamin. On the other hand, hepatic secretions of triacylglycerol, phospholipid and cholesterol were markedly lowered in rats fed sesamin, especially when exogenous fatty acid substrate was provided. The relative significance of the exogenous fatty acid was observed in the dietary sesamin-induced decrease in hepatic secretion of triacylglycerol. These results suggest that increased fatty acid oxidation by dietary sesamin, as reflected by enhanced ketone body production, leads to decreased partition of fatty acid substrates to the esterification pathways, and this in turn reduces the synthesis and secretion of triacylglycerol. The altered metabolism of exogenous fatty acids in the liver was therefore a major determinant for the synthesis and secretion of triacylglycerol.

Animals↗
PubMed1991

Hydrogenated oil decreases tissue concentrations of n-6 polyunsaturated fatty acids and may contribute to dyschondroplasia in broilers.

1. In a factorial design of dietary treatments, male Ross broilers were given diets containing soyabean oil, hydrogenated soyabean oil (as a source of trans-fatty acids) or feed fat with either 0 or 300 micrograms of added D-biotin/kg. 2. Growth to 28 d was not influenced by the dietary treatments. 3. Length of tibiotarsal bones was reduced (P less than 0.05) and severity of leg bone cartilage lesions, characteristic of dyschondroplasia, was highest (P less than 0.05) in broilers fed on diets containing hydrogenated soyabean oil. 4. Feeding hydrogenated soyabean oil lowered (P less than 0.05) the concentrations of C20:4n6 and the ratios of C20:4n6/C18:2n6 in liver and growth plate cartilage. 5. Growth plate cartilage from birds affected with dyschondroplasia contained lower proportions of prostaglandin precursor fatty acids compared with normal growth plate. 6. It is speculated that an inhibition of prostaglandin biosynthesis brought about by the presence of trans-fatty acids might contribute to the occurrence of lesions similar to dyschondroplasia.

Animal Feed↗
PubMed2002

Effect of dietary cholesterol, trans and saturated fatty acids on serum lipoproteins in non-human primates.

Nine cynomolgus monkeys were rotated randomly through four dietary treatments with each treatment lasting 6 weeks. A wash-out period of 4 weeks was maintained between each dietary rotation. The animals were fed diets containing 32% energy fat derived from palm olein (POL), lauric-myristic-rich oil blend (LM), American Heart Association (AHA) rich oil blend and hydrogenated soybean oil blend (trans). Diets were fed with (phase 1) or without (phase 2) the addition of dietary cholesterol (0.1%). In phase 1, when animals were fed without dietary cholesterol, plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) was significantly raised and high-density lipoprotein cholesterol (HDL-C) was significantly depressed by the trans diets relative to all other dietary treatments. The resulting LDL-C/HDL-C ratio was also significantly increased. The LM diet increased TC significantly relative to the AHA diet while LDL-C was significantly increased compared to both POL and AHA. Apolipoprotein (apo) B was not affected significantly by these dietary treatments. Apo A1 was significantly increased by POL relative to all other dietary treatments. The trans diet reduced apo A1 and the resulting apo B/A1 ratio was increased significantly by trans relative to all other dietary treatments. Addition of 0.1% dietary cholesterol to these diets almost doubled the plasma TC and LDL-C in all dietary treatments. However, HDL-C was only marginally higher with the addition of dietary cholesterol. The LM + C (cholesterol added) diet resulted in the highest TC and LDL-C that was significant compared to all other dietary treatments. Trans + C increased TC compared to POL + C and AHA + C diets while increases in the LDL-C did not attain significance. The addition of dietary cholesterol did not affect HDL-C between treatments whereas plasma triglycerides were significantly increased by the trans + C diet relative to all other treatments. Both the trans + C and LM + C diets increased apo B and decreased apo A1 relative to the POL + C and AHA + C diets. The resulting apo B/A1 ratio was similarly altered. These results affirm that the lauric + myristic acid combination, along with trans fatty acids, increased lipoprotein-associated coronary heart disease risk factors compared to either POL or AHA.

Animals↗
PubMed1999

Changing concepts in lipid nutrition in health and disease.

Fat remains a hot topic because of concerns over associations between consumption of fats and the incidence of some chronic conditions including coronary artery disease, diabetes, cancer and obesity. Dietary fats serve multiple purposes. The effects of dietary fats generally reflect the collective influences of multiple fatty acids in the diet or food. This presentation highlights some recent developments on the role of dietary fats and oils in health and disease. Debate continues over the role of dietary modification in coronary prevention by lipid lowering. The degree to which a recommended diet will result in health benefits for an individual is difficult to predict, because the outcome will depend on the influence of other factors such as a person's genetic constitution, level of physical activity and total diet composition. There can now be little doubt about the importance of genetic factors in the etiology of cardiovascular disease, diabetes, obesity and cancer. The importance of antioxidant status in the prevention of cardiovascular disease as well as many cancers is being increasingly recognised. It is now evident that not all saturated fatty acids are equally cholesterolemic. Recent accounts evaluating palm oil's effects on blood lipids and lipoproteins suggest that diets incorporating palm oil as the major dietary fat do not raise plasma total and LDL cholesterol levels to the extent expected from its fatty acid composition. Palm oil is endowed with a good mixture of natural antioxidants and together with its balanced composition of the different classes of fatty acids, makes it a safe, stable and versatile edible oil with many positive health and nutritional attributes. In recent times, adverse health concerns from the consumption of trans fatty acids arising from hydrogenation of oils and fats have been the subject of much discussion and controversy. Trans fatty acids when compared with cis fatty acids or unhydrogenated fats have been shown to lower serum HDL cholesterol, raise serum LDL cholesterol and when substituted for saturated fatty acids, increase lipoprotein Lp (a) level, an independent risk factor for the development of coronary heart disease. The idea of which foods, nutrients and supplements are "healthy" is often being amended as new scientific data is presented and then simplified for the consumers. What was once perceived as a healthy diet is often no longer considered as such and vice versa. Dietary recommendations have to change with time and the evidence available. Nutritional recommendations should encourage eating a great variety of nutrient sources within our food supply in moderation. Various lifestyle options to improve health should also be promoted.

Disease↗
PubMed1977

[Nutritional aspects of hydrogenated soy oils and their isomeric unsaturated fatty acids].

The results of long-term feeding experiments with three species of animals which received considerable amounts of soyabean oil hydrogenated in different ways confirm the safety-in-use of this type of product. Just like saturated or cis monoenoic fatty acids, monoenoic and polyenoic fatty acids with the trans configuration always have to be supplemented with an adequate amount of cis-cis linoleic acid. The unfavourable effects observed in rabbits after prolonged feeding with one of the studied hydrogenated fats were to be expected in view of the marginal amounts of linoleic acid present in the diet they received. In human nutrition, considering the limited use as such of that particular type of extremely hydrogenated fat with a high melting point, it can be concluded on the basis of present knowledge and with an ample safety margin, that the fats investigated have no unfavourable nutritional effects. With regard to the prevention of cardiovascular disease it is desirable to limit the amount of saturated, as well as trans fatty acids, in order to be able to supply an adequate amount of linoleic acid in the diet.

Animal Nutritional Physiological Phenomena↗
PubMed2005

[Dietary fatty acids and colorectal and prostate cancers: epidemiological studies].

OBJECTIVE: This study reviews epidemiological works having studied the associations of dietary fatty acids, especially of n-6 or n-3 polyunsaturated fatty acids (PUFA), with the risks of colorectal and prostate cancers. METHODS: The epidemiological studies reviewed were those having tested the association of colorectal and prostate cancer risk with the dietary intake or the blood or adipose tissue levels of fatty acids, especially of n-6 and n-3 PUFA, and with the dietary intake of fish and seafood. RESULTS: Most studies based on a dietary questionnaire did not find any association of the risk of colorectal cancer with the consumption of either total fatty acids or any particular fatty acid, after adjustment for total energy intake had been made. A few studies suggest that trans fatty acid consumption could increase colorectal cancer risk. Most studies based either on a dietary questionnaire or on biomarkers, did not find any association of total, saturated or monounsaturated fatty acid, as well as of linoleic or arachidonic acids, with prostate cancer risk, after adjustment for total energy intake. Most studies failed to find an association of prostate cancer risk with fish or long-chain n-3 PUFA intake, but recent cohort studies did find an inverse association of fish consumption with the risk of the latest stages of prostate cancer. In contrast, alpha-linolenic acid intake was associated with an increase of prostate cancer risk in a majority of epidemiological studies, but other studies did not find this association. This latter point might be of concern, and needs to be clarified by other results, especially those of ongoing prospective studies.

Animals↗