Palm and partially hydrogenated soybean oils adversely alter lipoprotein profiles compared with soybean and canola oils in moderately hyperlipidemic subjects

BACKGROUND: Partially hydrogenated fat has an unfavorable effect on cardiovascular disease risk. Palm oil is a potential substitute because of favorable physical characteristics. OBJECTIVE: We assessed the effect of palm oil on lipoprotein profiles compared with the effects of both partially hydrogenated fat and oils high in monounsaturated or polyunsaturated fatty acids. DESIGN: Fifteen volunteers aged > or =50 y with LDL cholesterol > or =130 mg/dL were provided with food for each of 4 diets (35 d/phase) varying in type of fat (partially hydrogenated soybean, soybean, palm, or canola; two-thirds fat, 20% of energy). Plasma fatty acid profiles, lipids, lipoproteins, apolipoprotein A-I, apolipoprotein B, lipoprotein(a), glucose, insulin, HDL subfractions, and indicators of lipoprotein metabolism (HDL-cholesterol fractional esterification rate, cholesteryl ester transfer protein, phospholipid transfer protein, and paraoxonase activities) were measured at the end of each phase. RESULTS: Plasma fatty acid profiles reflected the main source of dietary fat. Partially hydrogenated soybean and palm oils resulted in higher LDL-cholesterol concentrations than did soybean (12% and 14%, respectively; P < 0.05) and canola (16% and 18%; P < 0.05) oils. Apolipoprotein B (P < 0.05) and A-I (P < 0.05) concentrations mirrored the pattern of LDL- and HDL-cholesterol concentrations, respectively. No significant effect on the total-to-HDL cholesterol ratio was observed for palm oil compared with the other dietary fats. HDL3 cholesterol was higher after palm oil than after partially hydrogenated and soybean oils (P < 0.05). Differences in measures of glucose and HDL intravascular processing attributable to dietary fat were small. CONCLUSION: Palm and partially hydrogenated soybean oils, compared with soybean and canola oils, adversely altered the lipoprotein profile in moderately hyperlipidemic subjects without significantly affecting HDL intravascular processing markers.     

Home use of margarine is an important determinant of plasma trans fatty acid status: a biomarker study

The contribution of the home use of margarines, made with partially hydrogenated vegetables oils, to total trans fatty acid intake is difficult to determine using dietary assessment because food composition databases are incomplete for trans fatty acids; moreover, hidden fats in manufactured foods may be the predominant sources of trans fatty acids. The objective of our study was to determine, using plasma phospholipid trans fatty acid composition as a surrogate measure of exposure, whether the home use of margarine or butter is an important determinant of trans fatty acid status. We conducted a community-based (Dunedin, New Zealand), cross-sectional survey of people who consumed either margarine (n 65) or butter (n 64) but not both for home use. The levels of the 18:1 trans isomers commonly found in partially hydrogenated vegetable oils were all significantly higher in the plasma phospholipids of margarine compared with butter consumers, with the exception of 18:1n-7t, which did not differ. Among margarine consumers, the percentage of total fat from margarine was significantly correlated with levels of phospholipid 18:1n-6t, 18:1n-8t and 18:1n-12/9t isomers (r 0.57-0.63, P<0.001) but only weakly with 18:1n-7t (r 0.30, P=0.016). The intake of fat from fast foods, bakery products or meat and meat products was not associated with plasma phospholipid trans isomeric composition. The home use of margarine, made with partially hydrogenated vegetable oils, is an important determinant of trans fatty acid exposure in New Zealand.     

Exchanging partially hydrogenated fat for palmitic acid in the diet increases LDL-cholesterol and endogenous cholesterol synthesis in normocholesterolemic women

Partial hydrogenation of oil results in fats containing unusual isomeric fatty acids characterized by cis and trans configurations. Hydrogenated fats containing trans fatty acids increase plasma total cholesterol (TC) and LDL-cholesterol while depressing HDL-cholesterol levels. Identifying the content of trans fatty acids by food labeling is overshadowed by a reluctance of health authorities to label saturates and trans fatty acids separately. Thus, it is pertinent to compare the effects of trans to saturated fatty acids using stable isotope methodology to establish if the mechanism of increase in TC and LDL-cholesterol is due to the increase in the rate of endogenous synthesis of cholesterol. Ten healthy normocholesterolemic female subjects consumed each of two diets containing approximately 30% of energy as fat for a fourweek period. One diet was high in palmitic acid (10.6% of energy) from palm olein and the other diet exchanged 5.6% of energy as partially hydrogenated fat for palmitic acid. This fat blend resulted in monounsaturated fatty acids decreasing by 4.9 % and polyunsaturated fats increasing by 2.7%. The hydrogenated fat diet treatment provided 3.1% of energy as elaidic acid. For each dietary treatment, the fractional synthesis rates for cholesterol were measured using deuterium-labeling procedures and blood samples were obtained for blood lipid and lipoprotein measurements. Subjects exhibited a higher total cholesterol and LDL-cholesterol level when consuming the diet containing trans fatty acids while also depressing the HDL-cholesterol level. Consuming the partially hydrogenated fat diet treatment increased the fractional synthesis rate of free cholesterol. Consumption of hydrogenated fats containing trans fatty acids in comparison to a mixtur e of palmitic and oleic acids increase plasma cholesterol levels apparently by increasing endogenous synthesis of cholesterol.     

The effect of palm oil, lard, and puff-pastry margarine on postprandial lipid and hormone responses in normal-weight and obese young women

Only a few studies have been published on the postprandial effects of different fatty acids in obese subjects. Therefore, the present study investigated the effects of three test meals containing palm oil (PO), lard (LD), or puff-pastry margarine (PPM), all normal dietary ingredients, on postprandial lipid and hormone responses in normal-weight and obese young women. The study was performed as a randomized, crossover design. The fats differed in the content of palmitic acid, stearic acid, and trans monounsaturated fatty acids allowing a dietary comparison of different 'solid' fatty acids. The obese women had significantly higher fasting concentrations and postprandial responses of plasma total triacylglycerol (TAG), chylomicron-TAG, and insulin compared with the normal-weight women but there was no significant difference in the postprandial responses between the three test meals. The obese women had fasting concentrations of leptin four times greater than the normal-weight women. There were no postprandial changes in the concentrations of leptin. The fasting concentrations of HDL-cholesterol were significantly lower in the obese women than in the normal-weight women, whereas there was no significant difference between the two groups in the concentrations of total cholesterol or LDL-cholesterol. These results provide evidence that obese women have exaggerated lipid and hormone responses compared with normal-weight women but the different contents of saturated and trans monounsaturated fatty acids provided by PO, LD, and PPM have no effect in either group.     

Acute postprandial effect of hydrogenated fish oil, palm oil and lard on plasma cholesterol, triacylglycerol and non-esterified fatty acid metabolism in normocholesterolaemic males

The majority of research has focused on the association between trans unsaturated fatty acids (TUFA) from hydrogenated vegetable oils and heart disease even though TUFA are also produced from hydrogenated fish oil. We compared the acute effect of three solid fats on postprandial cholesterol, triacylglycerol (TAG) and NEFA concentrations in normocholesterolaemic males. Eight healthy male volunteers consumed each of the three 40 g fat meals (partially hydrogenated fish oil (PHFO), palm oil and lard) in random order and blood samples were drawn at 2, 4, 6 and 8 h thereafter for lipid analysis. The postprandial response in plasma TAG, TAG-rich lipoprotein-TAG (TRL-TAG), total cholesterol and plasma NEFA, measured as the area under the postprandial curve, was not significantly different between the three meals (P>0.05), which varied in MUFA, PUFA and TUFA content. There was no marked elevation of longer-chain fatty acids (C20-22, cis or trans isomers) into the TRL-TAG fraction following the PHFO meal even though they provided 40 % of the total fatty acids in the PHFO meal. The postprandial TRL-TAG response to PHFO was expected to be higher, as it is higher in TUFA, lower in PUFA and similar in saturated fatty acid composition compared with the lard and palm oil test meals. The absence of a higher postprandial response following ingestion of PHFO could be as a result of reduced absorption and increased oxidation of long-chain fatty acids (both cis and trans isomers).     

Intensification of essential fatty acid deficiency in the rat by dietary trans fatty acids

Two studies were conducted using male rats to assess the effect of trans fatty acids upon essential fatty acid (EFA) deficiency. In the first study 5% corn oil (CO), hydrogenated coconut oil (HCNO) or margarine stock (MS, partially hydrogenated soybean oil) were fed, and the levels of trans fatty acids in tissue lipids were measured. The trans fatty acids present in MS were found to intensify EFA deficiency and to be retained in tissue lipids to a high degree, especially in heart phospholipids (PL). In the second study, as the level of trans fatty acids increased in the diet, increasingly higher levels of trans fatty acids were deposited in the heart PL. As dietary trans acid increased, a decrease in total omega 6 fatty acids, and a decrease in the sum of 18:2 omega 6 + 20:4 omega 6 - 20:3 omega 9 fatty acids in heart PL occurred, both criteria indicating a shift toward an increasing EFA deficiency state. Studies of delta 5 desaturase activity of liver microsomes in selected groups showed an increase in the conversion of 20:3 omega 6 to 20:4 omega 6 as the trans fatty acid level in the diet increased.     

动植物油脂中反式脂肪酸测定方法的建立

目的建立适合国内条件的动植物油脂中反式脂肪酸测定方法,为国标方法提供依据。方法选择普通植物油、动物油和氢化植物油三个大类共9种动植物油脂样品,参照国际标准经部分修改,建立了适合国内条件的反式脂肪酸气相色谱分析及用面积归一法定量的测定方法,并进行了重复性测定和实验室间的验证。结果在实验条件下,油脂中脂肪酸可以得到很好的分离;除个别含量极低的脂肪酸外,各脂肪酸组分10次分析结果的相对标准偏差均小于10%,其中反式脂肪酸总和的RSD值在豆油和氢化豆油中分别是2.0%和0.3%;实验室间验证结果也表明,该方法在不同实验室间的结果有很好的一致性,豆油、氢化豆油、猪油三种样品的反式脂肪酸总和的RSD值分别是5.0%、1.1%和4.6%,均远小于10%。结论该检测方法实验室内和实验室间的精密度均较高,且所需仪器比较普及,操作步骤简单易行,分析时间短,适合国内开展,可作为我国动植物油脂反式脂肪酸的测定方法之一。     

Fatty acids composition of Greek margarines. Margarine consumption by the population of Crete and its relationship to adipose tissue analysis

Ten brands of margarines from the Greek market were analysed. The fatty acid (FA) composition was estimated by using gas liquid chromatography (GLC) with a capillary column. A sample of Cretan olive oil was used as a control. The brands of the same margarines were bought and analysed twice (June and October 1991) in order to observe differences between batches. During the second part of the study it was possible to distinguish between the cis and trans isomers of the unsaturated fatty acids. The ratios of polyunsaturated/saturated, monounsaturated/polyunsaturated and saturated/monounsaturated (P/S, M/P, S/M) fatty acids were calculated as well as the ω-6/ω-3 ratio. Four brands contained at least 40% saturated fatty acids. Trans double bonds were additionally regarded as simple bonds and the conventional ratios were recalculated. The amount of the 18:1 trans fatty acid ranged from 5.40 to 9.54% and that of cis-trans and trans-cis 18:2 fatty acids from 0.40 to 3.65%. The 18:2 trans-trans fatty acids ranged from 0 to 1.23%. Food consumption surveys in Crete showed that in selective population samples, margarine consumption was approximately 9 g/day for children and 2 g/day for adults. The analysis of fatty acids in adipose tissue of 70 Cretan lawyers showed 0.90 ± 0.25% (0.46–1.67) for 4 trans isomers of oleic acid and 0.14 ± 0.06% (0.05–0.31) and 0.04 ± 0.01% (0.02–0.06) for trans-cis and cis-trans isomers of linoleic acid respectively. Although margarine consumption in Crete is still low, trans fatty acids content is reflected in the adipose fatty acid composition. The industry must consider the potential health risks that consumption of such margarines will have on the population, and they must try to improve their products.     

Adequacy of essential fatty acid, vitamin D and vitamin E intake: Implications for the 'core' and 'extras' food group concept of the Australian Guide to Healthy Eating

Objective: To assess the implications of new recommendations for essential fatty acids, vitamin D and vitamin E on the classification of margarines and vegetable oils as ‘extras’ in the current Australian Guide to Healthy Eating. Design: The role of margarines and vegetable oils as sources of essential fatty acids, vitamin D and vitamin E was examined in two ways. First, data from the 1995 National Nutrition Survey were assessed and, second, sample diets conforming to the Australian Guide to Healthy Eating were modelled and analysed. Subjects: For the assessment of national intake, subjects were a representative sample of 13 858 Australians, surveyed in the 1995 National Nutrition Survey. Main outcome measures: Relative contributions of margarines and oils, the ‘core’ food groups and ‘extras’ categories of the Australian Guide to Healthy Eating to intakes of essential fatty acids and vitamins D and E; changes in nutrient profiles of baseline diets conforming to the Australian Guide to Healthy Eating with or without varying amounts of margarines and oils. Results: ‘Core’ foods and ‘extras’ contributed similar amounts of essential fatty acids and vitamins D and E to the Australian diet, margarines and oils being the major contributor among ‘extras’. The simulated low‐fat, low‐saturated‐fat baseline diets generally failed to meet the adequate intakes for n‐3 and n‐6 polyunsaturates and vitamin D, and vitamin E in some instances. The addition of 25 g of sunflower margarine, but not comparable amounts of canola margarine, olive oil and butter, markedly increased the ratio of polyunsaturated to saturated fatty acids and generally delivered the adequate intakes, vitamin D being the exception. Conclusion: The inclusion of margarines and vegetable oils in diets based on the current Australian Guide to Healthy Eating, and guidance on choice among these foods, is required to provide adequate intakes of linoleic acid, α‐linolenic acid and vitamins D and E and to achieve fatty acid profiles consistent with the prevention of chronic disease.     

A diet rich in coconut oil reduces diurnal postprandial variations in circulating tissue plasminogen activator antigen and fasting lipoprotein (a) compared with a diet rich in unsaturated fat in women

The effects of high and low fat diets with identical polyunsaturated/saturated fatty acid (P/S) ratios on plasma postprandial levels of some hemostatic variables and on fasting lipoprotein (a) [Lp(a)] are not known. This controlled crossover study compared the effects of a high fat diet [38.4% of energy (E%) from fat; HSAFA-diet, P/S ratio 0.14], a low fat diet (19.7 E% from fat; LSAFA-diet, P/S ratio 0.17), both based on coconut oil, and a diet with a high content of monounsaturated fatty acids (MUFA) and PUFA (38.2 E% from fat; HUFA-diet, P/S ratio 1.9) on diurnal postprandial levels of some hemostatic variables (n = 11) and fasting levels of Lp(a) (n = 25). The postprandial plasma concentration of tissue plasminogen activator antigen (t-PA antigen) was decreased when the women consumed the HSAFA-diet compared with the HUFA-diet (P = 0.02). Plasma t-PA antigen was correlated with plasminogen activator inhibitor type 1 (PAI-1) activity when the participants consumed all three diets (Rs = 0.78, P < 0.01; Rs = 0.76, P < 0.01; Rs = 0.66, P = 0.03; on the HSAFA-, the LSAFA- and the HUFA-diet, respectively), although the diets did not affect the PAI-1 levels. There were no significant differences in postprandial variations in t-PA activity, factor VII coagulant activity or fibrinogen levels due to the diets. Serum fasting Lp(a) levels were lower when women consumed the HSAFA-diet (13%, P < 0.001) and tended to be lower when they consumed the LSAFA-diet (5.3%, P = 0.052) than when they consumed the HUFA-diet. Serum Lp(a) concentrations did not differ when the women consumed the HSAFA- and LSAFA-diets. In conclusion, our results indicate that a coconut oil-based diet (HSAFA-diet) lowers postprandial t-PA antigen concentration, and this may favorably affect the fibrinolytic system and the Lp(a) concentration compared with the HUFA-diet. The proportions of dietary saturated fatty acids more than the percentage of saturated fat energy seem to have a beneficial influence on Lp(a) levels.     

Quality of margarine: fats selection and processing parameters

Optimum processing conditions on palm oil-based formulations are required to produce the desired quality margarine. As oils and fats contribute to the overall property of the margarine, this paper will review the importance of beta' tending oils and fats in margarine formulation, effects of the processing parameters -- emulsion temperature, flow-rate, product temperature and pin-worker speed -- on palm oil margarines produced and their subsequent behaviour in storage. Palm oil, which contributes the beta' crystal polymorph and the best alternative to hydrogenated liquid fats, and the processing conditions can affect the margarine consistency by influencing the solid fat content (SFC) and the types of crystal polymorph formed during production as well as in storage. Palm oil, or hydrogenated palm oil and olein, in mixture with oils of beta tending, can veer the product to the beta' crystal form. However, merely having beta' crystal tending oils is not sufficient as the processing conditions are also important. The emulsion temperature had no significant effect on the consistency and polymorphic changes of the product during storage, even though differences were observed during processing. The consistency of margarine during storage was high at low emulsion flow-rates and low at high flow rates. The temperature of the scraped-surface tube-cooler is the most important parameter in margarine processing. High temperature will produce a hardened product with formation of beta-crystals during storage. The speed of the pin-worker is responsible for inducing crystallization but, at the same time, destroys the crystal agglomerates, resulting in melting.     

Intake of trans fatty acid-rich hydrogenated fat during pregnancy and lactation inhibits the hypophagic effect of central insulin in the adult offspring

OBJECTIVE: Using rats we examined whether maternal intake of hydrogenated fat rich in trans fatty acids affects brain fatty acid profile, hypothalamic content of insulin receptor and insulin receptor substrate-1 proteins, and the hypophagic effect of centrally administered insulin in 3-mo-old male progeny. METHODS: Throughout pregnancy and lactation, Wistar rats ate isocaloric/normolipidic diets with soybean oil (control) or soybean oil-derived hydrogenated fat (trans diet) as a fat source. Upon weaning, the trans offspring continued on the trans diet (trans group) or were switched to a control diet (trans-control group). RESULTS: Compared with control rats, trans rats had lower brain levels of eicosapentaenoic acid. Compared with trans rats, trans-control rats had increased levels of total polyunsaturated fatty acids and arachidonic acid and decreased levels of trans fatty acids, saturated fatty acids, and monounsaturated fatty acids. Insulin receptor and insulin receptor substrate-1 levels were significantly lower (44% and 38%, respectively) in trans than in control rats. In trans-control rats, insulin receptor was 26% lower (P < 0.05), whereas insulin receptor substrate-1 was 50% lower, than in control rats. Insulin decreased 24-h feeding in control (27%) and trans (38%) rats but failed to do so in trans-control rats. The latter group had increased serum glucose levels. CONCLUSIONS: The data suggest that the early (intrauterine/perinatal) exposure to hydrogenated fat rich in trans fatty acids programmed the hypothalamic feeding control mechanisms. As young adults, only trans-control animals showed loss of insulin-induced hypophagia, indicating that the mismatch between early and later nutritional environments was relevant. However, the trans group also showed signs of altered appetite signaling mechanisms, suggesting that the early adaptations may have deleterious consequences later in life.     

Fatty acids and retinyl esters of rat milk: effects of diet and duration of lactation

This study was initiated to explore the quantitative and qualitative differences in milk total fatty acids and milk retinyl esters when either hydrogenated or nonhydrogenated fat is fed during pregnancy and lactation. Rats were fed diets containing 10% by weight of corn oil or partially hydrogenated corn oil. Milk was collected on d 1, 8 and 14 of lactation and analyzed for protein, total fatty acids, fatty acid pattern, and retinyl ester pattern. Whereas diet produced no quantitative differences in milk protein or total fatty acids, the pattern of milk fatty acids varied significantly. Rats fed corn oil produced milk having more medium-chain saturated fatty acids, less long-chain monoenoic fatty acids, and more polyunsaturated fatty acids compared to those fed hydrogenated corn oil. Rats fed hydrogenated corn oil produced milk fat having 21-26% of the trans fatty acid, elaidic acid. Significant differences were also observed with duration of lactation: medium-chain fatty acids increased three to fourfold between d 1 and 8, where cis-monoenes and polyunsaturated fatty acids declined. The pattern of milk retinyl esters strongly reflected, but was not identical to, that of total milk fat. Comparing d 14 milk from rats fed corn oil with that from rats fed hydrogenated corn oil, medium-chain esters of retinol constituted 24 and 11% of total retinyl esters, whereas saturated long-chain fatty acid esters constituted 52 and 44%, respectively. trans Fatty acid esters of retinol comprised 24% of vitamin A esters in milk of rats fed hydrogenated fat. These data provide evidence that the composition of milk retinyl esters, as well as that of total milk fat, is determined both by the type of fatty acids from diet and from diet-related differences in de novo synthesis of fatty acids within the mammary gland and other tissues.     

Absorption of very-long-chain saturated fatty acids in totally hydrogenated fish oil

Partially hydrogenated fish oil (PHFO) contains a high amount of trans fatty acids (TFA). Total hydrogenation results in a minimal amount of TFA, but a high content of very-long-chain saturated fatty acids (VLCSFA). Absorption and metabolism of VLCSFA from totally hydrogenated fish oil (THFO) were studied in rats. Groups of eight rats were fed one of four diets containing 40 g soyabean oil (SBO)/kg (low-fat diet), 150 g SBO/kg (SBO diet), 40 g PHFO/kg (PHFO diet) or 40 g THFO/kg (THFO diet) for 4 weeks. A lower absorption coefficient of the fat content was found in the THFO group (61 %) compared with the other groups (PHFO 95 %, SBO 99 %, low fat 98 %; which was mainly due to reduced absorption of VLCSFA. A reduced weight gain was found for the THFO group compared with the other groups, but this was only significant when compared with the SBO group Faecal fat excretion (dry weight) was markedly increased in the THFO group (47 %), which was 2.4, 4.8 and 8.3 times higher compared with the groups fed PHFO, SBO and low-fat diets respectively. Serum total cholesterol was reduced for the PHFO and THFO groups whereas serum triacylglycerol was increased for the PHFO group compared with the other groups Animals fed THFO diet had an increased content of 20:0 and 22:0 in the serum triacylglycerol fraction whereas only 20:0 was increased in the serum phospholipid fraction The low absorption coefficient of THFO must be considered if this fat is to be used for consumption by animals or man.     

High intakes of trans monounsaturated fatty acids taken for 2 weeks do not influence procoagulant and fibrinolytic risk markers for CHD in young healthy men

Dietary trans fatty acids are associated with increased risk of CHD. We hypothesized that the changes in plasma lipids associated with a high intake of trans fatty acids would cause adverse effects on procoagulant and fibrinolytic activities. A randomized crossover controlled feeding study was conducted in twenty-nine men. A trans-rich diet supplying 10 % energy as trans- 18:1 was compared with diets in which the trans fatty acids were replaced either with carbohydrate or oleate; each diet was taken for 2 weeks in random order. Fasting fibrinogen and d-dimer concentrations and factor VII coagulant, plasminogen activator inhibitor type 1 and tissue plasminogen activator did not differ between diets. Postprandially, tissue plasminogen activator activity increased and plasminogen activator inhibitor type 1 activity decreased on all diets. Factor VIIc increased postprandially by 15 and 17 % on the trans and oleate diets respectively, compared with an 11 % increase on the carbohydrate diet; the mean difference between oleate and carbohydrate diets was 6 (95 % CI 0.2, 11.9) %. The LDL-cholesterol:HDL-cholesterol and apolipoprotein B : apolipoprotein A-I ratios increased by 13 (95 % CI 5.7, 21.8) and 10 (95 % CI 3.1, 17.2) % respectively on the trans diet compared with the oleate diet and by 6 (95 % CI 0.1,12.7) and 7 (95 % CI 0, 13.5) % respectively compared with the carbohydrate diet. Plasma HDL2-cholesterol concentration was 18 (95 % CI 0.7, 35.9) % lower on the trans diet compared with the oleate diet. The results confirm adverse effects of trans fatty acids on HDL-cholesterol concentrations, but suggest that trans fatty acids do not have any specific effects on known haemostatic risk markers for cardiovascular disease in healthy young men in the short-term.     

Dietary conjugated linoleic acids and lipid source alter fatty acid composition of juvenile yellow perch, Perca flavescens

A study was conducted to examine the effects of dietary conjugated linoleic acids (CLA; 0, 0.5 or 1.0 g/100 g total CLA) and lipid source (menhaden oil, soybean oil or a 1:1 mixture of menhaden:soybean oil) on growth rates and fatty acid composition of yellow perch. Dietary treatments were fed to apparent satiation to triplicate groups of fish initially weighing 37.9 g/fish. At the end of the 9-wk feeding trial, no significant differences were detected in weight gain or feed intake among fish fed any of the dietary treatments. Dietary CLA, lipid source and/or their interaction significantly affected feed efficiency, total liver lipid concentration, and muscle and liver fatty acid concentrations. Feed efficiency (g gain/g feed) was significantly lower in fish fed diets containing soybean oil (0.51) compared with fish fed menhaden oil (0.58) or menhaden:soybean oil (0.60). Liver total lipid concentrations were significantly reduced in fish fed 0.5 and 1.0 g/100 g CLA compared with fish fed the diets containing no CLA and in fish fed menhaden oil compared with those fed soybean oil or a 1:1 mixture of menhaden:soybean oil. Total CLA levels increased in both liver and muscle as dietary CLA concentration increased, irrespective of lipid source. However, total CLA concentrations were significantly lower in liver and muscle of fish fed soybean oil. Total muscle CLA concentrations were 0, 1.26 and 2.92 g/100 g fatty acids in fish fed diets containing menhaden oil and 0, 0.5 and 1.0 g/100 g CLA, respectively. Mono- and polyunsaturated fatty acid (PUFA) concentrations were significantly lower in muscle and liver of fish fed CLA compared with fish fed the diets containing no CLA. In contrast, liver concentrations of saturated fatty acids, 14:0, 16:0 and 18:0, were significantly higher in fish fed 1.0 g/100 g CLA.     

Dietary trans alpha-linolenic acid from deodorised rapeseed oil and plasma lipids and lipoproteins in healthy men: the TransLinE Study

TRANS: isomers of alpha-linolenic acid, which are formed by deodorization of refined vegetable oils, can be found in significant amounts in edible oils. Effects of trans alpha-linolenic acid on plasma lipoproteins are unknown. We therefore investigated the effects of trans alpha-linolenic acid on plasma lipids and lipoproteins in healthy European men. Eighty-eight healthy men from three European countries (France, Scotland, UK and the Netherlands) first consumed for 6 weeks a diet with experimental oils 'free' of trans fatty acids (run-in period). For the next 6 weeks, they were randomly allocated to a diet with experimental oils 'high' or 'low' in trans alpha-linolenic acid. Daily total trans alpha-linolenic acid intake in the high trans group was 1410 (range 583-2642) mg. Experimental oils were provided as such, or incorporated into margarines, cheeses, muffins and biscuits. The high trans alpha-linolenic acid diet significantly increased the plasma LDL-:HDL-cholesterol ratio by 8.1 % (95 % CI 1.4, 15.3; and the total cholesterol:HDL-cholesterol ratio by 5.1 % (95 % CI 0.4, 9.9; compared with the low-trans diet. This was largely explained by an increase in LDL-cholesterol on the high-trans diet, while no change was observed in the low-trans group (mean treatment effect of 4.7 % (95 % CI -0.8, 10.5; No effects were found on total cholesterol and HDL-cholesterol, triacylglycerols, apolipoprotein B and A-1, and lipoprotein(a) concentrations. In conclusion, trans alpha-linolenic acid may increase plasma LDL-:HDL-cholesterol and total cholesterol:HDL-cholesterol ratios. Whether diet-induced changes in these ratios truly affects the risk for CHD remains to be established.     

Effect of plant sterols from rice bran oil and triterpene alcohols from sheanut oil on serum lipoprotein concentrations in humans

BACKGROUND: Intake of unsaponifiable compounds from edible oils, such as plant sterols, can lower serum cholesterol concentrations in humans. However, little is known about effects of other chemically related unsaponifiables in edible oils, such as triterpene alcohols. OBJECTIVE: We studied the effects of plant sterols from rice bran oil and triterpene alcohols from sheanut oil on cholesterol concentrations in healthy, normolipemic volunteers. DESIGN: Twenty-eight men and 32 women consumed 29 g/d of 3 margarines for 3 wk each on a crossover, double-blind basis. A margarine based on sunflower oil was used as the control. Concentrates of plant sterols from rice bran oil or triterpene alcohols from sheanut oil were added to make 2 experimental margarines with the same fatty acid composition as the control margarine. RESULTS: Intake of 2.1 g plant sterols/d from rice bran oil decreased total cholesterol by 0.19 mmol/L (95% CI: -0.31, -0.07 mmol/L) and LDL cholesterol by 0.20 mmol/L (95% CI: -0.30, -0.10 mmol/L). HDL-cholesterol and triacylglycerol concentrations did not change significantly. Intake of 2.6 g triterpene alcohols/d from sheanut oil did not significantly affect lipoprotein concentrations in all subjects combined. CONCLUSIONS: We found that 2.1 g plant sterols/d from rice bran oil lowered serum total cholesterol by 5% and LDL cholesterol by 9% in normolipemic humans, whereas triterpene alcohols from sheanut oil did not significantly affect lipoprotein concentrations in all subjects combined. The effect of rice bran oil sterols is probably due to ss-sitosterol and other 4-desmethylsterols and not to 4,4'-dimethylsterols.     

Dietary hydrogenated soybean oil affects lipid and vitamin E metabolism in rats

Fatty acids containing stearic acid, which are found in hydrogenated fat, may have a detrimental effect on the cholesterol and triacylglycerol (TAG) content of plasma lipoproteins, and on the absorption of fatty acids and fat-soluble vitamins. The aim of our study was to examine the tissue concentration of lipids and vitamins A and E after feeding a hydrogenated soybean oil (HSO) diet to rats. Twenty male Sprague-Dawley rats were randomly divided into two groups, fed on coconut oil (control) and HSO, respectively in amounts corresponding to 15% of the total feed. Plasma total cholesterol, VLDL- and LDL-cholesterol, lipid peroxidation and daily excretion of the TAG and cholesterol in feces were higher in the HSO than in the control group. TAG values in plasma and liver, and HDL-cholesterol levels in plasma were lower in the HSO than in the control group. The same was true for phospholipids in plasma and for saturated fatty acids, mono- and polyunsaturated fatty acids levels in the liver and vitamin E in plasma, LDL and adipose tissue. The results of this study provide new evidence concerning the effect of dietary hydrogenated fat on lipid, TAG and vitamin E status, which are important for maintenance of good health. Consumption of dietary HSO may be associated with cardiovascular disease.