Trans fatty acids. 2. Fatty acid composition of the brain and other organs in the mature female pig

Female pigs were fed from three wk of age and up to two years a diet containing partially hydrogenated fish oil (PHFO, 28%trans monoenoic fatty acids), partially hydrogenated soybean oils (PHSBO, 36%trans fatty acids) or lard. No consistent differences were found between PHFO and PHSBO with regard to incorporation oftrans fatty acids in organ lipids, buttrans incorporations were highly organ-specific. Notrans fatty acids were detected in brain phosphatidylethanolamine (PE). The incorporation of monoenoictrans isomers, as a percentage of totalcis + trans, in other organs was highest in subcutaneous adipose tissue and liver mitochondria PE, followed by blood lipids with the lowest level in heart PE. The percentage oftrans isomers compared with that of dietary lipids was consistently lower for 20∶1, compared with 18∶1 in organs from PHFO-fed pigs. The only effect of dietarytrans fatty acids on the fatty acid pattern of brain PE was an increased level of 22∶5n−6. Heart PE and total serum lipids of pigs fed the hydrogenated fats contained higher levels of 18∶2n−6, and these lipids of the PHFO-fed group also contained slightly elevated amounts of 20∶3n−6, 18∶3n−3 and 20∶5n−3. Liver mitochondria PE of the PHFO group also contained higher levels of 20∶3n−6 and 22∶5n−6. Dietarytrans fatty acids caused a consistent decrease of saturated fatty acids compensated by increased levels of monoenes. Thus, it may be concluded that dietary long-chaintrans fatty acids in PHFO behaved similarly metabolically to 18∶1-trans in PHSBO in pigs, without noticeable influence on brain PE composition and with moderate to slight effects on the fatty acid profile of the other organs.     

trans fatty acids, 5. Fatty acid composition of lipids of the brain and other organs in suckling piglets

The effects of dietarytrans fatty acids on the fatty acid composition of the brain in comparison with other organs were studied in 3-wk-old suckling piglets. In Experiment (Expt.) 1 the piglets were delivered from sows fed partially hydrogenated fish oil (PHFO) (28%trans), partially hydrogenated soybean oil (PHSBO) (36%trans) or lard (0%trans). In Expt. 2 the piglets were delivered from sows fed PHFO, hydrogenated fish oil (HFO) (19%trans) or coconut fat (CF) (0%trans) with two levels of dietary linoleic acid (1 and 2.7%) according to factorial design. In both experiments the mother's milk was the piglets' only food. The level of incorporation oftrans fatty acids in the organs was dependent on the levels in the diets and independent of fat source (i.e., PHSBO, PHFO or HFO). Incorporation oftrans fatty acids into brain PE (phosphatidylethanolamine) was non-detectable in Expt. 1. In Expt. 2, small amounts (less than 0.5%) of 18∶1trans isomers were found in the brain, the level being slightly more on the lower level of dietary linoleic acid compared to the higher. In the other organs the percentage of 18∶1trans increased in the following order: heart PE, liver mitochondria PE, plasma lipids and subcutaneous adipose tissue. Small amounts of 20∶1trans were found in adipose tissue and plasma lipids. Other very long-chain fatty acids from PHFO or HFO (i.e., 20∶1cis and 22∶1cis+trans) were found in all organ lipids except for brain PE. Dietarytrans fatty acids increased the percentage of 22∶5n−6 in brain PE. Except for the brain and the heart, dietarytrans fatty acids reduced the percentage of saturated fatty acids and increased the percentage of monoenoic acids (includingtrans). The overall conclusion was that dietarytrans fatty acids had no noticeable effect on the brain PE composition but slight to moderate effects on the fatty acid profile of other organs of suckling piglets.     

Dietary linoleic acid and polyunsaturated fatty acids in rat brain and other organs. Minimal requirements of linoleic acid

Starting three weeks before mating, 12 groups of female rats were fed different amounts of linoleic acid (18∶2n−6). Their male pups were killed when 21-days-old. Varying the dietary 18∶2n−6 content between 150 and 6200 mg/100 g food intake had the following results. Linoleic acid levels remained very low in brain, myelin, synaptosomes, and retina. In contrast, 18∶2n−6 levels increased in sciatic nerve. In heart, linoleic acid levels were high, but were not related to dietary linoleic acid intake. Levels of 18∶2n−6 were significantly increased in liver, lung, kidney, and testicle and were even higher in muscle and adipose tissue. On the other hand, in heart a constant amount of 18∶2n−6 was found at a low level of dietary 18∶2n−6. Constant levels of arachidonic acid (20∶4n−6) were reached at 150 mg/100 g diet in all nerve structures, and at 300 mg/100g diet in testicle and muscle, at 800 mg/100 g diet in kidney, and at 1200 mg/100 g diet in liver, lung, and heart. Constant adrenic acid (22∶4n−6) levels were obtained at 150, 900, and 1200 mg/100 g diet in myelin, sciatic nerve, and brain, respectively. Minimal levels were difficult to determine. In all fractions examined accumulation of docosapentaenoic acid (22∶5n−6) was the most direct and specific consequence of increasing amounts of dietary 18∶2n−6. Tissue eicosapentaenoic acid (20∶5n−3) and 22∶5n−3 levels were relatively independent of dietary 18∶2n−6 intake, except in lung, liver, and kidney. In several organs (muscle, lung, kidney, liver, heart) as well as in myelin, very low levels of dietary linoleic acid led to an increase in 20∶5n−3. Dietary requirements for 18∶2n−6 varied from 150 to 1200 mg/100 g food intake, depending on the organ and the nature of the tissue fatty acid. Therefore, the minimum dietary requirement is estimated to be about 1200 mg/100 g (i.e., the level that ensures stable and constant amounts of arachidonic acid).     

Fatty acid composition of liver lipids in rats fed brominated fatty acids

Feeding rats diets containing brominated corn oil or di- or tetrabromostearate as the monoglyceride produced changes in fatty acid composition of liver lipids. Those changes associated with the feeding of brominated corn oil or tetrabromosterates could be explained by the accumulation of triglyceride, and the changes associated with the feeding of dibromostearate could result from the proliferation of a membrane system. A unique response to the feeding of diets containing brominated corn oil is an increase in the level of γ-linolenic acid.     

Trans fatty acids: Positional specificity in brain lecithin

Fifteen-day-old rats were divided into three groups: one group received an intracerebral injection of 5 μ Ci of 9-trans, 12-trans [1-¹⁴C] octadecadienoic acid; the second group was given 5 μCi of the same compound plus an equal wt of nonradioactive allcis arachidonic acid; the third group was given 5 μCi of 9-trans [1-¹⁴C] octadecenoic acid. All animals were sacrificed 8 hr after injection. Glycerophosphocholine (GPC) was isolated and partically deacylated with phospholipase A₂ fromCrotalus Adamanteus venom. The results of this study were as follows: 1) aftert [1-¹⁴C] 18∶1 injection, there was twice as much radioactivity in the 1-position as in the 2-position; 2) whentt [1-¹⁴C] 18∶2 was injected, more than 90% of the total radioactivity was found in the 2-position; 3) followingtt[1-¹⁴C]-18∶2 +nonradioactive arachidonate injection, ca. 75% of the total radioactivity still remained in the 2-position; and 4) all of the injected [1-¹⁴C]-tracers showed evidence of undergoing β-oxidation to form acetyl-CoA, which was converted to radioactive palmitate. The possibility is discussed that the observed distribution pattern of the injected radioactive tracers may be attributed to tissue metabolic specificity. Ramifications of the deposition of dietarytrans fatty acids in the brain during the developmental stage of the central nervous system are also discussed.     

Fatty acid composition of rat hearts as influenced by age and dietary fatty acids

Fatty acid composition of neutral and polar lipid fractions from rat hearts was determined in rats of different ages as their diet source changed. Piebald rats were weaned at 21 days and were fed standard lab chow. Lipids from rat hearts, mothers milk and lab chow were purified on a Sephadex G-25 fine column and separated into neutral and polar lipid fractions by silicic acid column chromatography. These lipid fractions were then hydrolyzed and methylated with BF₃ in methanol, prior to gas liquid chromatographic separation on a 1/8 in. × 10 ft aluminum column of 15% EGS on 80–100 mesh acid-washed Chromosorb W. Three major fatty acids in the neutral lipid fraction comprised 72% of total neutral lipid fatty acids from young hearts. At sexual maturity (at least 74 days old) C_18∶1 was the major fatty acid, followed by C_16∶0 and C_18∶0. The same three fatty acids comprised 83% of total polar lipid fatty acids, but C_18∶0 was the major fatty acid, followed by C_16∶0 and C_18∶1. The fatty acid composition of dietary lipids influenced the total neutral lipid fatty acid composition of the rat heart, but had little influence on the fatty acid composition of the polar lipid fraction. Presented in part at the AOCS Meeting, New Orleans, April 1970.     

Fatty acid composition of danish margarines and shortenings,with special emphasis ontrans fatty acids

Trans fatty acids from hydrogenated vegetable and marine oils could be as hypercholesterolemic and atherogenic as saturated fatty acids. Hence, it is important to know the fatty acid composition in major food contributors, e.g., margarines and shortenings. In 1992 margarines were examined, and in 1995 brands covering the entire Danish market were examined. Significant amounts oftrans-18∶1 were found only in hard margarines (mean: 4.2±2.8%) and shortenings (mean: 6.8 ±3.1%), whereas the semisoft and soft margarines contained substantially lesstrans-18∶1 in 1995 than in 1992. Where marine oils had been used to a larger degree the meantrans-monoenoic content was about 15%, of which close to 50% was made up of long-chain (C₂₀ and C₂₂)trans fatty acids. A note-worthy decrease in the content oftrans-18∶1 had occurred for the semisoft margarines, from 9.8±6.1% in 1992 to 1.2±2.2% in 1995. Calculated from sales figures, the supply oftrans-18∶1 plus saturated fatty acids from margarines had decreased over this three-year period by 1.4 g/day, which has been replaced bycis monounsaturated and polyunsaturated fatty acids.     

Trans fatty acid composition and tocopherol content in vegetable oils produced in Mexico

The purpose of this study was to evaluate the trans fatty acid (TFA) composition and the tocopherol content in vegetable oils produced in Mexico. Sample oils were obtained from 18 different oil refining factories, which represent 72% of the total refineries in Mexico. Fatty acids and TFA isomers were determined by gas chromatography using a 100-m fused-silica capillary column (SP-2560). Tocopherol content was quantified by normal-phase high-performance liquid chromatography using an ultraviolet detector and a LiChrosorb Si60 column (25 cm). Results showed that 83% of the samples corresponded to soybean oil. Seventy-two percent of the oils analyzed showed TFA content higher than 1%. Upon comparing the tocopherol contents in some crude oils to their corresponding deodorized samples, a loss of 40–56% was found. The processing conditions should be carefully evaluated in order to reduce the loss of tocopherols and the formation of TFA during refining.     

Fatty acid composition of meat from ruminants, with special emphasis on trans fatty acids

The fatty acid composition was determined in 39 samples of beef, 20 samples of veal, and 34 samples of lamb, representative of the supply of ruminant meat in Denmark. Five cuts of beef and veal and three cuts of lamb with increasing fat content were selected, and analysis of the fatty acid methyl esters was performed by gas-liquid chromatography (GLC) on a polar 50-m capillary column CP Sil 88 with flame-ionization detection. Lamb had the highest content of saturated fatty acids (52.8±1.8 g/100 g fatty acids), higher than beef and veal (45.3±3.1 and 45.4±0.8 g/100 g fatty acids, respectively). Cis monounsaturated fatty acids were 49.2±3.1, 44.9±1.8, and 37.7±1.7, and polyunsaturated fatty acids were 3.3±0.7, 5.8±2.0, and 5.0±0.1 g/100 g fatty acids in beef, veal, and lamb, respectively. Beef contained 2.1±0.8 g trans C_18:1 per 100 g fatty acids, about half that found in veal (4.0±1.2 g/100 g fatty acids) and lamb (4.5±0.6 g/100 g fatty acids). Trans C_16:1 was 0.24±0.01, 0.14±0.02, and 0.79±0.02 g/100 g fatty acids in beef, veal, and lamb, respectively. Only small variations in trans and other fatty acids could be demonstrated between cuts. The overlap between cis and trans C_18:1 by capillary GLC was verified by argentation-thin-layer chromatography followed by GLC, on three samples of veal and three samples of lamb. In veal 1.0 g, and in lamb 1.4 g trans C_18:1 per 100 g fatty acids were hidden under the cis C_18:1 peak. The mean intake of trans fatty acids from ruminant meat is estimated at 0.2 g/d.     

trans fatty acids. 4. Effects on fatty acid composition of colostrum and milk

trans Isometric fatty acids of partially hydrogenated fish oil (PHFO) consist oftrans 20∶1 andtrans 22∶1 in addition to thetrans isomers of 18∶1, which are abundant in hydrogenated vegetable oils, such as in partially hydrogenated soybean oil (PHSBO). The effects of dietarytrans fatty acids in PHFO and PHSBO on the fatty acid composition of milk were studied at 0 (colostrum) and 21 dayspostpartum in sows. The dietary fats were PHFO (28%trans), or PHSBO (36%trans) and lard. Sunflower seed oil (4%) was added to each diet. The fats were fed from three weeks of age throughout the lactation period of Experiment 1. In Experiment 2 PHFO or “fully” hydrogenated fish oil (HFO) (19%trans), in comparison with coconut oil (CF) (0%trans), was fed with two levels of dietary linoleic acid, 1 and 2.7% from conception throughout the lactation period. Feedingtrans-containing fats led to secretion oftrans fatty acids in the milk lipids. Levels oftrans 18∶1 andtrans 20∶1 in milk lipids, as percentages of totalcis+trans 18∶1 andcis+trans 20∶1, respectively, were about 60% of that of the dietary fats, with no significant differences between PHFO and PHSBO. The levels were similar for colostrum and milk. Feeding HFO gave relatively lesstrans 18∶1 andtrans 20∶1 fatty acids in milk lipids than did PHFO and PHSBO. Only low levels ofcis+trans 22∶1 were found in milk lipids. Feedingtrans-containing fat had no consistent effects on the level of polyenoic fatty acids but reduced the level of saturated fatty acids and increased the level ofcis+trans monoenoic fatty acids. Increasing the dietary level of linoleic acid had no effect on the secretion oftrans fatty acids but increased the level of linoleic acid in milk. The overall conclusion was that the effect of dietary fats containingtrans fatty acids on the fat content and the fatty acid composition of colostrum and milk in sows were moderate to minor.     

Effect of low intake of n−3 fatty acids during development on brain phospholipid fatty acid composition and exploratory behavior in rats

The effect of dietary restriction of n−3 fatty acids during development on brain phospholipid fatty acid composition and exploratory behavior has been studied in male Sprague Dawley rats. Female rats were fed semipurified diets containing either 5.5% safflower oil or 6% soybean oil for 6 wk prior to mating and throughout gestation and lactation. Control rats were maintained on laboratory chow. The male pups were weaned to the diets of the dams except for one group which was switched from safflower to soybean oil at weaning. Behavioral studies and brain phospholipid analyses were conducted at 16–18 wk of age. Rats fed safflower oil showed significantly lower levels of 22∶6n−3 in phospholipids of synaptic membranes and myelin than rats fed soybean oil or chow. The decrease in 22∶6n−3 was compensated for by an increase in 22∶5n−6, the total content of polyunsaturated fatty acids remaining approximately constant. The brain phospholipid fatty acid composition of rats switched from safflower to soybean oil at weaning was similar to that of rats fed soybean oil throughout the experiment. There was no difference in spontaneous locomotor activity among the different dietary groups. However, rats raised on safflower oil displayed a significantly lower exploratory activity (horizontal movements and rearings) in a novel environment than rats fed soybean oil or chow. In contrast to the brain phospholipid fatty acid composition, there was no recovery of exploratory behavior in rats raised on safflower oil and switched to soybean oil at weaning suggesting a specific requirement of n−3 fatty acids during development.     

Fatty acid composition of French infant formulas with emphasis on the content and detailed profile oftrans fatty acids

The aim of the present study was to identify and quantitatetrans isomers of C18 fatty acids in some French infant formulas. Twenty powdered infant formulas were purchased in pharmacies and supermarkets in order to assess theirtrans mono- and poly-unsaturated fatty acids content. The fatty acid profiles were examined using methyl and isopropyl ester derivatives. The combination of gas-liquid chromatography, high-performance liquid chromatography, and silver nitrate thin-layer chromatography was needed to describe the detailed fatty acid compositions of the samples, includingtrans isomers of unsaturated C18 fatty acids. All the samples containedtrans isomers of C18∶1 acid (mean level 1.97±0.28% of total fatty acids), with vaccenic acid being generally the major isomer (15 out of 20 samples), thus indicating the origin from bovine milk. All the formulas also contained various isomers of linoleic and α-linolenic acids, but at lower levels.Trans PUFA isomers are the same as those present in deodorized oils. In conclusion, all the infant formulas analyzed in this study contained sometrans fatty acids, including isomers of essential fatty acids. This should be taken into account in the dietary intake of the newborn.     

Fatty acid composition of brain glycerophospholipids in peroxisomal disorders

This paper shows for the first time the differential fatty acid composition of ethanolamine plasmalogens (EP) and phosphatidylethanolamine (PE) in the brains of 12 patients with disorders of peroxisomal biogenesis and compares the results to normal values for the age. Other important glycerophospholipids (GPL), such as phosphatidylserine (PS) and phosphatidylcholine (PC), are also included in this study. GPL were separated by two-dimensional thin-layer chromatography, and their fatty acid composition was determined by capillary column gas-liquid chromatography. Total brain GPL were slightly decreased in peroxisomal disorders (27.98±2.95 μmol/g in the patients against 34.5±6.21 μmol/g in age-matched controls, P=0.005), and the distribution of the different GPL classes was much altered. In confirmation of known data, EP were very much decreased (2.18±1.3 μmol/g in the patients against 6.9±2.3 μmol/g in controls) at the expense of PE, which was increased (8.58±2.17 μmol/g in the patients against 5.97±0.58 μmol/g in controls, P<0.005). PS and PC were both significantly decreased (P=0.0001 and P=0.037, respectively). The polyunsaturated fatty acid (PUFA) composition of all the GPL fractions was markedly abnormal. In absolute terms, docosahexaenoic acid (22∶6n−3) was drastically decreased in all GPL classes (always at the P<0.0001 level) while arachidonic acid (20∶4n−6) was increased in PE and PS (P<0.001 in both cases). In the alkenyl acyl form, EP, 22∶6n−3, and 20∶4n−6 were both very significantly decreased (P<0.0001), although the former was always the most affected. The myelin PUFA adrenic acid (22∶4n−6) was decreased in EP (P<0.0001) and slightly increased in PS (P<0.05). The changes found confirm that 22∶6n−3 deficiency is a predominant defect in the brain in peroxisomal disorders.     

Fatty acid metabolism in the calanoid copepodParacalanus parvus: 1. Polyunsaturated fatty acids

The metabolic fate of radioactive linoleate and α-linolenate administered to the South Atlantic copepodParacalanus parvus was studied. The wild copepod was able to incorporate the labeled acids dissolved in seawater. The radioactive linoleate was elongated to 20∶2ω6 and 22∶2ω6 and desaturated by a Δ6 desaturase to 18∶3ω6. α-Linolenate was also desaturated by a Δ6 desaturase to 18∶4ω3 and elongated to 20∶3ω3. The copepod was able to convert α-18∶3 to 20∶5ω3 and 22∶6ω3. Member of the Carrera del Investigador Científico of the Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Member of the Carrera del Investigador Científico of the Consejo Nacional de Investigaciones Cientificas y Tècnicas.     

n−3 Fatty acid requirements of the newborn

Whether docosahexaenoic acid (22∶6n−3) is an essential nutrient for term or preterm infants, or if not, the quantity of dietary linolenic acid (18∶3n−3) needed to support sufficient synthesis of 22∶6n−3 for assimilation in the central nervous system is unknown. Infants fed formulas have lower plasma and red blood cell (RBC) levels of 22∶6n−3 than breast fed infants. No relationship between the intake of 18∶3n−3 in formula (0.8 or 4.5% of fatty acids, 18∶2n−6/18∶3n−3 ratio 35∶1 or 7∶1, respectively) and the infant's RBC 22∶6n−3 was found. Premature infants (<33 wk gestation) also showed a decrease in RBC 22∶6n−3 during feeding with formula containing 18∶3n−3 as the only n−3 fatty acid. However, a marked decrease in plasma and RBC 22∶6n−3 occurred between premature birth and the start of full enteral feeding at 1–2 wk of age. This was not reversed by breast milk or formula feeding. Piglets, which are appropriate for studies of infant lipid metabolism, had decreased brain synaptic plasma membrane, retina and liver 22∶6n−3 and increased 22∶5n−6 when fed formula with 0.8% fatty acids (0.3% of kcal) as 18∶3n−3. Formula with 4.0% fatty acids (1.7% of kcal) as 18∶3n−3 resulted in similar accretion of 22∶6n−3 in the organs compared to milk fed animals. The studies suggest the dietary requirement for 18∶3n−3 in term animals in energy balance exceeds 0.3% diet kcal. Studies in the premature infants suggest 18∶3n−3 may be oxidized rather than desaturated to 22∶6n−3 if energy requirements are not met, and that due to early lipid restriction and later rapid growth, premature infants may have higher dietary n−3 requirements than term infants. Based on a paper presented at the Symposium on Milk Lipids held at the AOCS Annual Meeting, Baltimore, MD, April 1990.     

Fatty acid composition and glyceride structure of piglet body fat from different sampling sites

Pigs were slaughtered at 16 weeks of age, and fat samples were obtained from outer and inner shoulder, outer and inner loin, and kidney. Fatty acid composition and glyceride type of distribution were determined. Glyceride structure was determined by pancreatic lipase hydrolysis. There were highly significant differences in fatty acid composition between sites. Fatty acids containing less than 18 carbon atoms were preferentially incorporated in the internal positions of the glycerides. The content of saturated fatty acids and fatty acids containing less than 18 carbon atoms at the 2-position of shoulder and loin glycerides was higher than in kidney glycerides. Differences in glyceride types were noted between sites.     

Fatty acid and 3‐hydroxy fatty acid composition of two Hypericum species from Turkey

The fatty acid compositions of flowering tops of Hypericum perforatum L. and Hypericum retusum Aucher (Guttiferae) were analyzed by gas chromatography and gas chromatography‐mass spectrometry. The major components were C16:0 (24.87%), C18:3 n‐3 (21.94%), 3‐OH‐C18:0 (18.46%) and 3‐OH‐C14:0 (14.22%) for H. perforatumL. and 3‐OH‐C14:0 (28.29%), C18:0 (16.47%) and C16:0 (14.17%) for H. retusum Aucher. Besides widespread plant fatty acids, 3‐hydroxy fatty acids, namely 3‐hydroxytetradecanoic acid (3‐OH‐C14:0) and 3‐hydroxyoctadecanoic acid (3‐OH‐C18:0) were also obtained.     

Fatty acid composition of subcellular particles from sheep platelets and topological distribution of phosphatidylethanolamine fatty acids in the plasma membrane

The fatty acid composition of individual phospholipids in subcellular fractions of sheep platelets and the asymmetrical distribution of phosphatidylethanolamine (PE) fatty acyl chains across the plasma membrane were examined. The main fatty acids of total lipid extracts were oleic (18∶1; 32–41%), linoleic (18∶2, 10–17%), stearic (18∶0; 13–15%), palmitic (16∶0; 11–15%) and arachidonic (20∶4; 8–12%) acids, with a saturated/unsaturated ratio of about 0.4. Each phospholipid class had a distinct fatty acid pattern. Sphingomyelin (SM) showed the highest degree of saturation (50%), with large proportions of behenic (22∶0), 18∶0 and 16∶0 acids. The main fatty acid in PE, phosphatidylserine (PS) and phosphatidylcholine (PC) was 18∶1n−9. Our findings suggest that fatty acids are asymmetrically distributed between thecholineversus the non-choline phospholipids, and also between plasma membranes and intracellular membranes. The transbilayer distribution of PE fatty acids in plasma membranes from non-stimulated sheep platelets was investigated using trinitrobenzenesulfonic acid (TNBS). A significant degree of asymmetry was found, which is a new observation in a non-polar cell. The PE molecules from the inner monolayer contained higher amounts of 18∶2 and significantly less 18∶1 and 20∶5 than those found in the outer monolayer, although no major differences were detected in the transbilayer distribution of total unsaturatedversus saturated PE acyl chains.