Influence of moderate amounts of trans fatty acids on the formation of polyunsaturated fatty acids

Prolonged consumption of trans fat favors the development of orofacial dyskinesia and anxiety-like symptoms in older rats

Polyunsaturated fatty acids (FAs) are cell membrane components involved in brain functions. We hypothesized that long-term trans fat consumption is able to modify the membrane FAs composition impairing behavioral parameters related to aging. In this study, a comparison of behavioral parameters at 10 and 15 months of trans fat consumption by male Wistar rats was made. Animals were fed for 10 and 15 months from weaning with diets containing either 20% w/w soybean oil (SO), rich in n-6 PUFA, hydrogenated vegetable fat (HVF), rich in trans FAs, or a standard diet (control - C). At both evaluation times, HVF-fed rats showed progressively increased parameters of orofacial dyskinesia, fear and anxiety-like symptoms. The HVF diet reduced locomotor and exploratory activities progressively over 10 and 15 months of supplementation, while the standard and SO diets did not. In this study, we showed that chronic trans FAs consumption from weaning is able to favor the development of neuromotor and neuropsychiatric diseases, whose intensity was time dependent.

Effect of modified dairy fat on fasting and postprandial haemostatic variables in healthy young men

It has been suggested that milk fat, due to its content of saturated fatty acids, may have a thrombogenic effect. In the present study the fatty acid profile of milk fat was modified by changing the feeding regimens of cows and the effect on haemostatic variables of a diet containing the modified milk fat (M) was compared with that of a diet containing milk fat of typical Danish composition (D). In the modified fat 16% of the saturated fatty acid (C12–C16) content was replaced mainly by oleic acid. Eighteen subjects were fed on two strictly controlled isoenergetic diets containing 40% energy from total fat (30% energy from the test fats) for periods of 4 weeks in a study with a crossover design. Fasting samples were taken in the last week of each study period. Postprandial samples were taken on day 21, 3 h after lunch (n18), and on the last day of the study 2, 4, 6 and 8 h after a fat load containing 1·2 g of one of the milk fats/kg body weight (n8). After 4 weeks' dietary intervention fasting plasma factor VII coagulant (FVIIc) activity, tissue-type plasminogen activator (t-PA) activity, plasminogen activator inhibitor (PAI-1) antigen and β-thromboglobulin did not differ between diets M and D. Postprandially FVIIc and t-PA activities increased (P< 0·001) and PAI-1 antigen and PAI-1 activity decreased (P< 0·001) as compared with fasting values, regardless of diet. After the fat load, the postprandial increase in FVIIc was marginally lower after diet M than diet D (diet effect,P< 0·05). In conclusion, the modified milk fat obtained by the applied feeding strategy had virtually the same effects on haemostatic variables as conventional milk fat.

Increase of geometrical and positional fatty acid isomers in dark meat from broilers fed heated oils

Oxidation of polyunsaturated fatty acids leads to primary and secondary oxidation products. Compounds and amounts of these products vary, depending on the oxidative conditions. Because these oxidation products have different absorption and biological effects, we performed 2 different heating treatments on sunflower oil. The first was heating the oil at 190 to 195 degrees C for 28 h (i.e., very oxidized oil), and the other was heating at 60 degrees C for 12 d (i.e., peroxidized oil). In the frame of this study, we compared the fatty acid composition of a refined sunflower oil (fresh oil), peroxidized oil, very oxidized oil, and a mixture (1:1) of fresh and very oxidized oil (i.e., oxidized oil). Oil fatty acid compositions were affected by the heating treatments. In addition, different fatty acid isomers were formed during heating at 190 to 195 degrees C, and significant differences were found between their contents in the sunflower oils. We also studied the effect of feeding broilers with these oils and Zn and tocopherol supplements on the fatty acid composition of their raw dark meat. Various trans fatty acid isomers increased in dark meat from broilers fed oxidized and very oxidized oils. In addition, discriminant analysis showed that ditrans-conjugated linoleic acid content was able to distinguish dark chicken meat from chickens fed sunflower oils heated at 190 to 195 degrees C.

Effects of long-term dietary lipids on mature bone mineral content, collagen, crosslinks, and prostaglandin E2 production in Japanese quail

This study investigated the effects of long-term dietary lipids on mature bone mineral content, collagen concentration, crosslink levels, bone marrow and ex vivo prostaglandin E2 (PGE2) biosynthesis, as well as the relationship of PGE2 production to these bone formation parameters. One-month-old male Japanese quail were given a basal diet containing 1 of 4 lipid sources: soybean oil (SBO), hydrogenated soybean oil (HSBO), chicken fat (CF), or menhaden fish oil (FO) at 50 g/kg of the diet. At 8 mo of age, lipid treatments did not affect bone length, diameter, or weight in quail. Quail fed SBO or CF had significantly lower levels of mineral content in tibial bones compared with those given FO. Bone collagen level was significantly higher in quail consuming SBO than those given HSBO or CF. Collagen crosslink concentration was markedly increased in birds provided FO or HSBO compared with those fed SBO or CF. Prostaglandin E2 biosynthesis in bone organ culture and marrow were greatly increased in quail maintained on the SBO or CF diet compared with those given the FO or HSBO diet. Prostaglandin E2 production in the bone microenvironment was negatively correlated with tibial ash and collagen crosslinks but had a positive correlation with tibial collagen levels. These results support our previous findings that long-term exposure to diets high in SBO or CF impaired mature bone mechanical properties and histological characteristics. Further, the results suggest that long-term supplementation of SBO or CF in the diet had a significant adverse effect on mature bone metabolism, and that dietary lipids altered bone metabolism, perhaps partially by controlling the production of local regulatory factor in bone.

Efeito da gordura vegetal parcialmente hidrogenada sobre a incorporação de ácidos graxos trans em tecidos de ratos

A composição lipídica da dieta pode influenciar o perfil de ácidos graxos dos tecidos. O objetivo do presente estudo foi avaliar a incorporação de ácidos graxos trans no fígado e coração de ratos. Dois grupos com doze ratos Wistar recém-desmamados foram alimentados com duas dietas diferentes por oito semanas. Uma das dietas (experimental) foi rica em isômeros trans (33,0% da fração lipídica) e apresentou quantidades mínimas de ácidos linoléico e alfa-linolênico (8,0% e 0,7%, respectivamente, da fração lipídica da dieta), enquanto a outra (controle) foi nutricionalmente adequada. O perfil de ácidos graxos das dietas e dos tecidos foi avaliado por cromatografia gasosa. Houve incorporação de 14,0% dos ácidos graxos trans no fígado e 8,6% no coração dos animais. Não foi observado efeito inibitório dos ácidos graxos trans no fígado sobre a formação dos ácidos araquidônico e docosahexaenóico. No entanto, no coração houve uma diminuição significante da concentração do ácido docosahexaenóico, provavelmente como reflexo da deficiência de ácido a-linolênico e da incorporação dos trans.

Maternal dietary lipids modify composition of bone lipids and ex vivo prostaglandin E2 production in early postnatal Japanese quail

This study examined the effects of maternal dietary lipids on fatty acid composition and ex vivo prostaglandin E2 (PGE2) biosynthesis in bone tissues of progeny of Japanese quail. Laying hens were fed a basal diet containing soybean oil (SBO), hydrogenated soybean oil (HSBO), poultry fat (PF), or menhaden fish oil (FO) at 50 g/kg of diet. Fertilized eggs were incubated, and newly hatched quail were used for tibial fatty acid analysis and PGE2 measurement or were fed an identical diet until 2 wk of age. Yolks and tibiae of newly hatched quail from hens fed the SBO diet contained higher levels of total n-6 fatty acids and arachidonic acid [AA; 20:4(n-6)], whereas those from hens consuming the FO diet had increased concentrations of total n-3 fatty acids, eicosapentaenoic acid [EPA; 20:5(n-3)], docosapentaenoic acid [22:5(n-3)], docosahexaenoic acid [DHA; 22:6(n-3)], and total saturated fatty acids (SAT) but greatly reduced amounts of AA in egg yolks and tibiae. The maternal diet containing HSBO resulted in the accumulation of trans 18:1 egg yolks and tibiae of newly hatched quails. At 1 wk of age, the concentrations of EPA, DHA, and trans 18:1 in tibiae still reflected the maternal dietary fatty acid profile. At 2 wk of age, however, differences in fatty acid composition between treatments had disappeared. Addition of FO or HSBO to the maternal diet significantly lowered the ex vivo PGE2 production of tibiae in newly hatched quail compared to those from hens fed SBO or PF diet. These results suggest that maternal dietary lipids may have the potential to influence bone metabolism of embryos by modifying the fatty acid composition of this tissue.

Influence of dietary partially hydrogenated fat high in trans fatty acids on lipid composition and function of intestinal brush border membrane in rats

The effect of dietary hydrogenated fat (Indian vanaspati) high in trans fatty acids (6 en%) on lipid composition, fluidity and function of rat intestinal brush border membrane was studied at 2 and 8 en% of linoleic acid. Three groups of weanling rats were fed rice-pulse based diet containing 10% fat over a ten week period: Group I (groundnut oil), Group II (vanaspati), Group III (vanaspati + safflower oil). The functionality of the brush border membrane was assessed by the activity of membrane bound enzymes and transport of D-glucose and L-leucine. The levels of total cholesterol and phospholipids were similar in all groups. The data on fatty acid composition of membrane phospholipids showed that, at 2 en% of linoleic acid in the diet, trans fatty acids lowered arachidonic acid and increased linoleic acid contents indicating altered polyunsaturated fatty acid metabolism. Alkaline phosphatase activity was increased while the activities of sucrase, gamma-glutamyl transpeptidase and transport of D-glucose and L-leucine were not altered by dietary trans fatty acids. However at higher intake of linoleic acid in the diet, trans fatty acids have no effect on polyunsaturated fatty acid composition and alkaline phosphatase activity of intestinal brush border membrane. These data suggest that feeding dietary fat high in trans fatty acids is associated with alteration in intestinal brush border membrane polyunsaturated fatty acid composition and alkaline phosphatase activity only when the dietary linoleic acid is low.