Showing papers on "Docosahexaenoic acid published in 1992"

Trans fatty acids may impair biosynthesis of long-chain polyunsaturates and growth in man.

Abstract: Human diet contains large amounts of trans fatty acids originating primarily from hydrogenated fats. Consumption of trans fatty acids is considered safe for man, but side effects, including impaired biosynthesis of long-chain polyunsaturated fatty acids with 20 and 22 carbon atoms and reduced growth have been observed in animals. We studied whether or not there are indications of untoward effects of trans fatty acids in 29 premature infants (birth weight 1700 +/- 127 g, gestational age 33.6 +/- 1.4 weeks, mean +/- SD). Plasma samples obtained on day 4 of life were analysed for fatty acid composition. Trans octadecenoic acid and total trans fatty acids in plasma lipid fractions (% wt/wt) were not related to the precursor essential fatty acids linoleic and alpha-linolenic acids but correlated inversely to n - 3 and n - 6 long-chain polyunsaturated fatty acids and to the product/substrate ratios of long-chain polyunsaturate biosynthesis. Trans fatty acids were also inversely correlated to birth weight but not to gestational age. These data indicate a potential impairment of essential fatty acid metabolism and early growth by trans isomers in man, and question the safety of high dietary trans isomer intakes during pregnancy and the perinatal period.

Lipids of selected molds grown for production of n-3 and n-6 polyunsaturated fatty acids.

Abstract: The lipid classes and component fatty acids of seven fungi were examined. Three marine fungi,Thraustochytrium aureum, Thraustochytrium roseum andSchizochytrium aggregatum (grown at 30, 25 and 25°C, respectively), produced less than 10% lipid but contained docosahexaenoic acid (DHA) up to 30% and eicosapentaenoic acid (EPA) up to 11% of the total fatty acids.Mortierella alpinapeyron produced 38% oil containing solely n-6 polyunsaturated fatty acids (PUFA) with arachidonic acid (AA) at 11% of the total fatty acids.Conidiobolus nanodes andEntomorphthora exitalis produced 25% oil and contained both n−3 and n−6 PUFA, with AA at 16% and 18%, respectively.Saprolegnia parasitica produced 10% oil and contained AA and EPA, respectively, at 19% and 18%. The triacylglycerol fraction always represented the major component at between 44% and 68% of the total lipid. Each fungus, exceptT. aureum, had the greatest degree of fatty acid unsaturation in the phospholipid fraction. The triacylglycerol fraction ofT. aureum was the most unsaturated with DHA representing 29% (w/w) of all fatty acids present. The presence of the enzyme ATP:citrate lyase correlated with the ability of molds to accumulate more than 10% (w/w) lipid when the fungi were grown in nitrogen-limiting media. In those molds that failed to accumulate more than 10% lipid, the enzyme was absent.

Omega-3 fatty acid content of the US food supply.

Abstract: In this study, levels and sources of omega-3 fatty acids (FA) available for consumption in the US food supply, dating from 1935, are estimated. omega-3 FA assessed are eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and linolenic acid (LNA). Estimates are based on annual per capita food use data and data on the omega-3 FA content of foods. Although fish use increased, the EPA level was slightly lower in 1985 than in 1935-1939, reflecting a marked decline in use of certain fatty fish. The level of DHA increased, due to greater use of poultry. The level of LNA increased because of greater use of soybean oil. These estimates are currently the only source of data on omega-3 FA in the American diet.

Concentration of docosahexaenoic acid in glyceride by hydrolysis of fish oil withcandida cylindracea lipase

Abstract: In an attempt to concentrate the content of DHA (docosahexaenoic acid) in a glyceride mixture containing triglyceride, diglyceride and monoglyceride, fish oil was hydrolyzed with six kinds of microbial lipase. After the hydrolysis, free fatty acid was removed and fatty acid components of the glyceride mixtures were analyzed. When the hydrolysis withCandida cylindracea lipase was 70% complete, the DHA content in the glyceride mixture was three times more than that in the original fish oil. The EPA (eicosapentaenoic acid) content became almost 70% of the original fish oil. Hydrolysis with other lipases did not result in an increase in the DHA content in the glyceride mixtures. Hydrolysis of DHA-rich tuna oil (DHA content is about 25%) withCandida cylindracea lipase resulted in 53% DHA in the glyceride mixture. The EPA content, however, remained close to that of the original tuna oil. In this report, the acyl chain specificity of lipases is evaluated in terms of hydrolysis resistant value (HRV). HRV is the ratio between the DHA contents in the glyceride mixture of hydrolyzed oil and original oil. HRV clearly indicates differences in hydrolysis between DHA and other fatty acids (e.g., saturated and monoenoic acids).

Manipulation of the fatty acid composition of pig meat lipids by dietary means

Abstract: Pigmeat products have been associated with an unhealthy image due to the relative proportions of polyunsaturated and saturated fatty acids. The aim of this experiment was to improve the fatty acid profile of the carcass fat by feeding various dietary sources of fat. Groups of 10 female Large While × Landrace pigs were fed one of four experimental diets. Five in each group were slaughtered at 70 kg live weight and the remaining five at 100 kg live weight. The diets were offered ad libitum and daily intake was recorded. The diets were based on barley, soya bean meal and fishmeal. Diet 1 contained 50 g tallow kg−1, a relatively saturated fat, and diets 2, 3 and 4 contained 50 g soya oil kg−1, an unsaturated fat. Diet 3 also contained 7.5 g GLA oil kg−1, which is rich in gamma linolenic acid, with the aim of increasing the production of arachidonic acid in the body fat. Diet 4 was supplemented with 9.5 g EPAnoil kg−1, which is rich in eicosapentaenoic acid and docosahexaenoic acid. There were no significant differences between dietary treatments in performance (daily liveweight gain or the efficiency of food conversion to liveweight gain) of the pigs slaughtered at 70 kg live weight, but small differences were observed at 100 kg live weight, where pigs on treatments 2, 3 and 4 performed slightly better than those on treatment 1. At both slaughter weights the lipid content of the m semitendinosus was higher than that of the m longissimus dorsi (approximately 24 and 13 g kg−1, respectively). The pattern of fatty acids in the dietary fat was reflected to varying degrees in the carcass fat. Diet 1 resulted in the highest levels of palmitic, palmitoleic, stearic and oleic acids whereas diets 2, 3 and 4 gave high levels of linoleic and linolenic acids. The extra gamma linolenic acid in diet 3 did not result in a consistently significant increase in the production of arachidonic acid. The supplement of EPAnoil gave significant increases in the levels of eicosapentaenoic and docosahexaenoic acids in the body lipids. The polyunsaturated to saturated fatty acid ratio of the body lipid was increased with diets 2, 3 and 4 to about 1.0. In spite of high levels of linoleic acid, there were no adverse effects during the processing of the carcasses and the taste panel evaluation did not reveal any treatment differences.

Essentiality of dietary omega 3 fatty acids for premature infants: plasma and red blood cell fatty acid composition.

Abstract: Pre-term infants, that are not breast-fed, are deprived of vital intrauterine fat accretion during late pregnancy and must rely on formula to obtain fatty acids essential for normal development, particularly of the visual system. Preterm infants (30 wk postconception) receiving human milk were compared to infants given one of the following formulae: Formula A was a commercial preterm formula with predominantly 18:2 omega 6 (24.2%) and low (0.5%) 18:3 omega 3; Formula B was based on soy oil and contained similar 18:2 omega 6 levels (20%) and high 18:3 omega 3 (2.7%); Formula C was also a soy oil-based formula (20% 18:2, 1.4% 18:3) but was supplemented with marine oil to provide omega 3 long-chain polyunsaturated fatty acids (LCP) at a level (docosahexaenoic acid, DHA, 0.35%) equivalent to human milk. At entry (10 days of age), the fatty acid composition of plasma and red blood cell (RBC) membrane lipids of the formula groups were identical. By 36 wk postconception, the DHA content in lipids of group A was significantly reduced compared to that in the human milk and marine oil formula groups. Omega-3 LCP results were further amplified by 57 wk with compensatory increases in 22:5 omega 6 in both plasma and RBC lipids. Provision of 2.7% alpha-linolenic acid in formula group B was sufficient to maintain 22:6 omega 3 levels equivalent to those in human milk-fed infants at 36 wk but not at 57 wk. Effects on the production of thiobarbituric acid reactive substances and fragility of RBC attributable to the marine oil supplementation were negligible. The results support the essentiality of omega 3 fatty acids for preterm infants to obtain fatty acid profiles comparable to infants receiving human milk. Formula for preterm infants should be supplemented with omega 3 fatty acids including LCP.

Effect of fish oil on the fatty acid composition of human milk and maternal and infant erythrocytes.

Abstract: To examine the effect of fish oil supplementation on the fatty acid (FA) composition of human milk and maternal and infant erythrocytes, five lactating women were supplemented with 6 g of fish oil daily for 21d. Usual maternal diets contained 1,147 mg of total n−3 FA, with 120 mg from very long-chain (>C18) n−3 FA. Supplementation increased dietary levels to 3,092 mg of total n−3 FA and 2,006 mg of very long-chain n−3 FA. Milk samples were collected daily, prior to fish oil ingestion, and at 4-h intervals on days 1, 7, 14 and 21. Milk n−3 FA content increased within 8 h and reached steady state levels within one week. The n−6 fatty acid content decreased. Erythrocyte eicosapentaenoic acid content increased from 0.24% to 1.4% (P<0.01) in mothers and from 0.11% to 0.70% (P<0.05) in infants. Docosapentaenoic acid increased from 1.4% to 2.2% (P<0.05) in mothers and from 0.30% to 0.78% (P<0.01) in infants. There was no significant change in docosahexaenoic acid or n−6 fatty acid content. Maternal platelet aggregation responses were variable. No differences in milk or plasma tocopherol levels were noted.

Effect of dietary supplementation with n-3 polyunsaturated fatty acids on physical properties and metabolism of low density lipoprotein in humans.

Abstract: The effects of marine n-3 polyunsaturated fatty acids were investigated in relation to the chemical and physical properties of low density lipoprotein (LDL) and how these changes affected LDL metabolism in humans. The subjects received supplements of six capsules daily, each capsule containing 1 g of either highly concentrated ethyl esters of n-3 fatty acids (85% eicosapentaenoic acid and docosahexaenoic acid) (n = 12) or corn oil (56% linoleic and 26% oleic acid) (n = 11). After 4 months of oil supplementation, the following changes were observed in the lipid moiety of the n-3-enriched LDL particles compared with LDL from the corn oil group: LDL cholesteryl ester, as well as the amount of total lipids of LDL, was significantly lower (0.97 +/- 0.12 versus 1.19 +/- 0.23 mg/mg protein and 1.88 +/- 0.40 versus 2.45 +/- 0.31 mg/mg, respectively; mean +/- SD, n = 6, p less than 0.05); the amount of eicosapentaenoic and docosahexaenoic acids and the unsaturation index increased (104.0 versus 29.4 micrograms/mg protein and 6.64 versus 5.49, respectively); and differential scanning calorimetry showed that LDL cholesteryl ester melting temperature was lowered by 2 degrees C (27.6 +/- 0.8 degrees versus 29.5 +/- 0.2 degrees C). The only effect observed on the protein moiety was an increase in the ratio of apolipoprotein (apo) B to cholesterol (0.66 +/- 0.17 versus 0.82 +/- 0.14 mg/mg cholesterol; p less than 0.05). Circular dichroism spectra of LDL indicated an alpha-helix content of 46 +/- 5% in apo B from both groups. No difference was observed by 13C nuclear magnetic resonance spectroscopy in the ratio of "active" to "normal" lysine residues of apo B. No detectable differences in the size of n-3 fatty acid-enriched LDL particles versus control LDL could be measured by either electron microscopy of negatively stained LDL (24.5 +/- 2.0 versus 25.0 +/- 1.5 nm) or dynamic light scattering (24.9 +/- 0.9 versus 24.9 +/- 0.4 nm). LDL from the fish oil and corn oil groups showed similar susceptibility to Cu(2+)-catalyzed lipid peroxidation, as indicated by the amount of lipid peroxides formed during the oxidation time, and degradation of oxidatively modified LDL in J774 macrophages as a function of Cu2+ oxidation time. No effect of n-3 fatty acids was observed on LDL metabolism. Specific uptake and degradation of n-3 fatty acid-enriched LDL were similar to those for control LDL in HepG2 cells as well as in human skin fibroblasts, and they showed the same ability to stimulate cholesteryl ester synthesis.(ABSTRACT TRUNCATED AT 400 WORDS)

Nutritional role of polyunsaturated fatty acids

Abstract: In mammalian tissues there are four families of polyunsaturated fatty acids derived from the parent fatty acids: palmitoleic and oleic acids, which can be synthesized endogenously, and linoleic and linolenic acids, which must be obtained from the diet and are known as essential fatty acids. These four precursors are desaturated and chain elongated to form the long chain highly unsaturated fatty acids. The principal products of linoleic acid are arachidonic, with four double bonds (tetraene), and dihomogamma linolenic acids; those of linolenic acid are eicosapentaenoic and docosahexaenoic acids. These polyunsaturated acids derived from essential fatty acids when incorporated into membrane phospholipids can alter membrane fluidity, which determines the permeability of membranes and the behavior of membrane-bound enzymes and receptors. The dihomogammalinolenic, arachidonic, and eicosapentaenoic acids are also the precursors of eicosanoids, which influence many cellular processes. When the dietary amounts of linoleic and linolenic acids are inadequate, palmitoleate and oleate are desaturated and chain elongated to give rise to eicosatrienoic acids (triene). An elevated tissue triene/tetraene ratio is, therefore, used as a marker for essential fatty acid deficiency. The essential fatty acid deficiency symptoms include reduced growth rate, scaly dermatitis, impaired reproduction, and susceptibility to infection. The intake of 1 to 2% of the daily calories as linoleate and 0.2 to 0.5% as linolenate is widely acknowledged as the approximate amounts to meet the needs of essential fatty acids in humans

Docosahexaenoic Acid Status of Term Infants Fed Breast Milk or Infant Formula Containing Soy Oil or Corn Oil

Abstract: Docosahexaenoic Acid Status of Term Infants Fed Breast Milk or Infant Formula Containing Soy Oil or Corn Oil

Changing Fatty Acid Content of Growth Cone Lipids Prior to Synaptogenesis

Abstract: The developing mouse was used to assess biochemical changes in membrane lipids during the period when nerve growth cones become synapses. Growth cone particles and synaptosomes were simultaneously obtained from common brain homogenates. Incorporation of the essential fatty acid, docosahexaenoic acid (22:6ω-3), was correlated with the developmental changes in endogenous fatty acid content of growth cones and synaptosomes. Analysis of endogenous lipid content indicated that, at all ages studied, the growth cones contained more arachidonoyl acyl chains (20:4ω-6) than did synaptosomes. Before the onset of synaptogenesis, levels of arachidonoyl chains increased and levels of 22:6, oleoyl and linoleoyl chains decreased in synaptosomes. Although stearoyl and palmitoyl (16:0) remained stable in synaptosomes, 16:0 decreased in growth cones. With the exception of 16:0 and 20:4, endogenous fatty acyl content of growth cones and synaptosomes became similar by postnatal day 10, which coincides with the onset of synaptogenesis. When 5-day-old mouse pups were injected intraperitoneally with [3H]22:6, the incorporation into growth cone and synaptosome phospholipids was greatest in phosphatidylethanolamine, followed by phosphatidylser-ine and phosphatidylcholine. Nominal labeling was present in phosphatidic acid and phosphatidylinositol. Labeling in neutral lipids was less than that of phospholipids, with tria-cylglycerol incorporating most of the neutral lipid label, followed by diacylglycerol and free 22:6. Only the growth cone fraction contained detectable amounts of 22:6-labeled cholesterol esters. The distribution of 22:6 label in plasma 72 h after injection indicated that ∼60% of the label was in phospholipids with ∼40% in neutral lipids and <5% in free fatty acids. Collectively, the data indicate that changes in fatty acid composition occur during the conversion of growth cones to synapses.

Fat Characteristics of Pigs Fed Fish Oil Containing Eicosapentaenoic and Docosahexaenoic Acids

Abstract: Sixteen pigs averaging 81.4 kg were assigned to a control diet and three test diets containing 2, 4, or 6% fish oil. Subcutaneous fat samples from the loin were obtained by biopsy at weekly intervals and analyzed for fatty acid composition. The pigs were maintained on the diets (ad libitum access to feed) for 4 wk before slaughter at an average weight of 107.8 kg. Outer and inner layers of backfat, perirenal fat, and intermuscular fat were obtained from the carcass and analyzed for physicochemical characteristics. In the biopsy samples, the contents of eicosapen- taenoic. acid (EPA) and docosahexaenoic acid (DHA) in fat from pigs fed fish oil began to increase during the 1st wk. Rates of increase were greater during the first 2 wk than during the last 2 wk. In the carcass samples, the increase in EPA and DHA in all fat tissues analyzed became greater as the supplemental levels of fish oil were increased in the diet, whereas oleic and linoleic acids tended to be decreased by increases in EPA and DHA. Color of fat was not significantly different among the control and fish oil groups. With the increase in fish oil in the diet, the hardness of fat measured with a texturometer was decreased. The refractive index and the iodine number were increased. As for differences among anatomical locations, it was noted that EPA and DHA contents of perirenal fat were higher than those of backfat and intermuscular fat. These results indicate that porcine adipose tissues rich in EPA and DHA can be produced by feeding fish Oil.

Composition, functionality, and sensory evaluation of eggs from hens fed dietary menhaden oil

Abstract: Enrichment of omega-3 fatty acid content of egg yolk may increase consumer acceptance of egg products if eggs maintain characteristic functionality, exhibit compositional stability, and are sensorially acceptable. The diet of laying hens was enriched with 3% menhaden oil. Arachidonic acid (20:4n-6) was decreased 70.2%, and linolenic (18:3n-3) and docosahexaenoic acid (22:6n-3) were increased 78.5% and 356%, respectively, in egg yolk. Eicosapentaenoic acid (20:5n-3) was also incorporated into test egg yolk as compared to nondetectable levels in control eggs. Cooking did not alter the fatty acid composition of eggs nor were functional properties of test eggs affected. Panelists differentiated n-3 enriched eggs from controls (P ≤ 0.01) when scrambled but not when hard cooked.

Antimalarial properties of n-3 and n-6 polyunsaturated fatty acids: in vitro effects on Plasmodium falciparum and in vivo effects on P. berghei.

Abstract: The polyunsaturated fatty acids docosahexaenoic acid (C22:6,n-3), eicosapentaenoic acid, arachidonic acid, and linoleic acid caused marked in vitro growth inhibition of Plasmodium falciparum, assessed by a radiometric assay. In contrast, negligible parasite killing was seen with oleic acid or docosanoic acid. Parasite killing was significantly increased when oxidized forms of polyunsaturated fatty acids were used. Antioxidants greatly reduced the fatty acid-induced killing. Mice infected with P. berghei and treated for 4 d with C22:6,n-3 showed marked reduction in parasitemia. The anemia associated with the infection was also alleviated by treatment with C22:6,n-3. The data provide new information that could be explored in order to develop new strategies in malaria treatment.

Antioxidant properties of individual phospholipids in a salmon oil model system

Abstract: The antioxidant properties of phospholipids (PL) in a refined salmon oil model system were measured by determining changes in the 2-thiobarbituric acid number and decreases in the ratio of docosahexaenoic acid (DHA)/palmitic acid (22:6/16:0) of a fish oil system incubated at 180°C for up to 3 h. The more phosphatidylcholine (PC) added to the oil system, the higher the oxidative stability obtained. The order of effectiveness of commercial phospholipids in inhibiting oxidation and the loss of polyunsaturated fatty acids was as follows: sphingomyelin (SPH)=lysophosphatidylcholine (LPC)=phosphatidylcholine (PC)=phosphatidylethanolamine (PE)>phosphatidylserine (PS)>phosphatidylinositol (PI)>phosphatidylglycerol (PG)>control salmon oil. Nitrogen containing PL, including PE, PC, LPC and SPH, were equally effective in exerting greater antioxidant properties than PS, PG and PI. The inverse relationship observed between the oxidation index (C22:6/C16:0) and color intensity for treatments following 2 h of heating suggests that Maillard-type reaction products may have contributed to the oxidative stability of PL-supplemented fish oils.