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Introducción: el tipo de ácido graso de la dieta presenta diferentes efectos sobre la obesidad y sus complicaciones, pero estos efectos pueden verse influenciados por los genes y sus polimorfismos, tales como los receptores activados por el proliferador de los peroxisomas isoforma γ2 (PPARγ2). Además, no está claro si el grado de insaturación de los lípidos posee diferentes efectos en el metabolismo de los lípidos y de la glucosa y, particularmente, en la pérdida de peso. Objetivos: evaluar la influencia de dietas ricas en ácidos grasos poliinsaturados (AGPI) y monoinsaturados (AGMI) en las variables antropométricas y bioquímicas en el peso corporal y el perfil glucémico y lipémico en mujeres obesas con el genotipo Pro12Pro en el gen PPARγ2. Métodos: dieciocho mujeres obesas con genotipo Pro12Pro fueron distribuidas aleatoriamente para una de las dietas, rica en AGPI (n = 8) o AGMI (n = 10). Las variables antropométricas (índice de masa corporal [IMC] y circunferencia de la cintura) y bioquímicas (glucosa, insulina, HOMA-IR, colesterol total, LDL-colesterol, HDL colesterol y triglicéridos) fueron evaluadas antes y después de un periodo de 45 días. Resultados: las variables antropométricas y bioquímicas fueron similares entre los grupos antes y después de la intervención (p > 0,05). El IMC disminuyó después de la ingesta de AGPI (p = 0,01), probablemente debido al menor contenido de lípidos. El AGMI redujo la glucosa (p = 0,03), insulina (p = 0,03) y HOMA-IR (p = 0,02). Conclusión: los AGMI fueron más eficientes para reducir la resistencia a la insulina en mujeres obesas con el genotipo Pro12Pro en el gen PPARγ2, aunque las mujeres presentaran una elevada ingesta de lípidos totales y ácidos grasos saturados.

We analyzed in 31 subjects, regular guests of the University food service of the Central University of Venezuela (UCVFS), in Caracas, the effects of replacing sunflower oil, commonly used in the preparation of meals, by a mix of sunflower oil and palm olein 70/30 (v/v) respectively. Plasma concentrations of total cholesterol, low and very low density lipoproteins were not changed after 40 days of the substitution. On the contrary, concentrations of high density lipoprotein and total triglycerides increased. The resistance to the oxidation of low-density lipoproteins increased considerably (p < 0.01). Today this resistance is considered as a protective factor of great importance in the prevention of the initiation of the atherogenic process. Taking into account the favorable modifications of HDL cholesterol and the clear increased resistance to the oxidation of LDL, we think that palm olein, mixed with other oils with a high ratio linoleic/palmitic (sunflower, corn, soya an the likes), can be used as a healthy alternative in human nutrition.

Palm oil is rich in carotenoids, tocopherols and tocotrienols. This oil is refined for its human consumption bringing as a consequence an alteration of their properties. The objective of this study was to evaluate the effect of the partially refined, bleached and deodorized palm oil (RBD red) on the lipid profile and levels of vitamin A (retinol) and E (alpha tocopherol) in 4 groups of rats: B (commercial food Protinal for laboratory animals: ST + 5% egg yolk powder); C (ST + 5% egg yolk powder + 14 RBD red) both groups with induced hyperlipidemia; and D (ST + 14% RBD red), as compared with a control A (ST) during 35 days. The results were: the RBD red induced significative decreases of TC (total cholesterol) in groups C and D (81 +/- 11 mg/dL and 77 + 7 mg/dL), respectively, when compared with the control group (99 +/- 11 mg/dL) for 35 days experimentation. Additionally, an increment of the HDL-C (53 +/- 4 mg/dL) in the C group and in the D group (53 +/- 5 mg/dL) were observed when compared with group B (44 +/- 3 mg/dL), resulting in a lower ratio of TC/HDL-C (1.5 +/- 0.1). In the groups C and D, there were significant increases (p < 0.05) in the serum concentrations of retinol (26 +/- 5 microg/dL and 58 +/- 18 microg/dL) and a tocopherol (165 +/- 58 microg/dL) and 445 +/- 65 microg/dL). These results allow to conclude that the supplementation with RBD red diminishes the TC, improving the ratio TC/HDL-C. The presence of a monosaturated fatty acid (oleic acid) and the high concentrations of micronutrients (a tocopherol and retinol) in RBD red palm oil, influence favorably the lipid profile of rats with induced hyperlipidemia.

Background: Dietary tocopherols, tocotrienols and saturated, mono and polyunsaturated fatty acids have been reported to have an effect on blood lipid profiles. In Colombia, vegetable oils (palm, soy, corn, sunflower, and canola) are a common dietary constituent and consumed in high quantities., Objective: In the current study, the effects of vegetable oil consumption was examined by measuring blood concentrations of triglycerides (TG), total cholesterol (TC) and HDL cholesterol (HDL-C) in male Wistar rats., Methods: The concentrations of tocopherols, tocotrienols, and fatty acids in each oil was quantified by High Performance Liquid Chromatography (HPLC). Each rat diet was supplemented with 0.2 ml/day with one oil type. Over a 4-week period, groups of animals were sacrificed weekly and blood samples were obtained to quantify TC, TG and HDL-C for each oil class. Statistical analyses included mean, standard deviation, ANOVA and Bonferroni comparisons tests., Results: Triglyceride content was not affected except in the control and the soy group in the third treatment week, although a tendency for decreased TG was noted in the palm oil group and for increased TG in the sunflower oil and canola oil groups. No significant differences in total cholesterol were observed. In HDL-C, significant differences were present for every treatment week (p = 0.005); this represented a decreasing trend in palm oil group and an increasing trend in the sunflower and corn oil groups., Conclusion: The oils effected changes in the blood lipid profile. A small amount of saturated fatty acids (tocopherol and tocotrienol) were favourable for the HDL-C increase. The presenct of tocorienols tended to decrease the TG and probably helped attenuate the unfavorable effects of the saturated fatty acids.

Background and Objective: Several epidemiological and experimental studies have associated the intake of antioxidants, which are abundant in the Mediterranean diet, with a low incidence of cardiovascular disease. One possible mechanism of this action is the oxidative protection in low density lipoproteins (LDL). The aim of our study was to compare the antioxidative activity of diverse phenolic compounds present in virgin olive oil on these lipoproteins., Subjects and Method: LDL was isolated from blood plasma of healthy volunteers by sequential ultracentrifugation. This was followed by oxidation with CuC12 in the presence of different concentrations of phenolic compounds and virgin olive oil extract. Production of conjugated dienes was determined by the continuous monitoring of increased absorbency at 234 nm as an indicator of LDL oxidation., Results: Virgin olive oil extract prolonged the latency phase and significantly lowered the progression rate (p < 0.05) at low concentrations (2 g/ml). This antioxidative effect was also observed with low concentrations (2 M) of caffeic acid and oleuropein (p < 0.05). However, it was necessary to increase the concentration of flavone up to 50 times to observe a similar effect (p < 0.05)., Conclusion: Both virgin olive oil extract enriched in phenolic compounds and phenolic compounds present in olive oil (caffeic acid and oleuropein) are potent antioxidants at very low concentrations. Thus, the beneficial effects of a Mediterranean diet may be partly due to the protective action of these compounds.

Background: To investigate the protective effect of several olive oils with different phenolic composition on low density lipoprotein susceptibility to oxidation., Patients and Methods: Refined olive oil (phenolic content: 0 mg/l caffeic acid equivalents [CAE]), common olive oil (0.1 and 0.3 mg/l CAE), and virgin olive oil diluted with refined olive oil (0.1 y 0.3 mg/l CAE), were added to isolated low density lipoprotein. Conjugated dienes formation was monitored after copper-mediated low density lipoprotein oxidation., Results: An increase in the lag time of conjugated dienes formation after copper-mediated low density lipoprotein oxidation was observed linked to olive oil phenolic content (p < 0.0001, ANOVA). Multiple regression analysis showed that phenolics were the most significant antioxidants with 0.1 mg/l--increase in phenolic concentration, adjusted for alpha-tocopherol and beta-carotene, was 72 minutes (95% confidence interval [CI] 64 to 80 min) for common olive oil, and 111 min (CI 95%: 100-123 min) for virgin olive oil. In common olive oil alpha-tocopherol levels were significatively associated with the increase in the lag time (p = 0.003), reaching in virgin olive oil a borderline significant (p = 0.084)., Conclusions: Olive oil containing phenolics showed more antioxidant effect on low density lipoprotein oxidation than refined olive in relation to its phenolic content. The nature of the phenolic content influences the antioxidant capacity of an olive oil.

Unlabelled: FOUNDATIONS: The dietary oil provides a significant portion of the caloric intake in the form of fat, although there is some controversy with respect to the potential positive action of each type of oil. In this study, the effect on the lipo-apoprotein profile of monounsaturated fatty acids (MUFA) provided by olive oil and the polyunsaturated fatty acids (PUFA) provided by girasol oil are compared in a population with high risk of arteriosclerosis, as it is the aged population., Methodology: 44 aged patients living in the same institution, 21 males and 23 females (age: 79 +/- 6 years), and following two different diets during 3 months, with olive and girasol oils, respectively, participated in the study. Both diets were isocaloric: 2.300 kcal/day, 17% proteins, 33% lipids (30 g/day of oil), and 50% carbohydrates. Plasmatic concentrations of cholesterol (C), triglycerides (TG), c-LDL, c-VLDL, c-HDL2, c-HDL3 and lipoprotein a (Lp[a]), as well as apoproteins A1, B, CII, CIII and E, were assessed. Applied statistics: Student's t test for matched samples., Results: C and TG plasmatic levels did not changed, whereas levels of c-LDL decreased significantly, as well as levels of polyunsaturated fatty acids (135 +/- 43 and 124 +/- 33 mg/dl., p < 0.009) and levels of apo B (151 +/- 47 and 139 +/- 36 mg/dl., p < 0.009). Levels of c-HDL increased significantly (49 +/- 14 and 52 +/- 16 mg/dl., p < 0.01) as well as levels of apo A1 (190 +/- 32 and 205 +/- 41 mg/dl., p < 0.01). Levels of apo CIII (8.2 +/- 2.8 and 9.9 +/- 3.2 mg/dl., p < 0.008) and apo E (3.2 +/- 1.1 and 3.7 +/- 0.9 mg/dl., p < 0.01) also increased in men. Women did not showed any significant variations in lipoproteins, although apo A1 and apo E increased slightly and apo B decreased, although not significantly, with the polyunsaturated fat. The levels of Lp(a) did not changed., Conclusions: In the aged population following a standard diet, without overloads, the PUFAs induced positive changes in the lipoapoprotein profile when compared to a previous diet with MUFA. Those changes were more evident in men than in women.

The effect of dietary polyunsaturated fatty acids (PIFA) upon the content of reduced glutathione (GSH) of the kidney was studied in 32 male Wistar rats. Two equal size groups were fed diets supplemented with either 10% or 18% corn oil. Sixteen hours before death, half of each experimental group was submitted to fasting. The content of GSH and the activity of gamma glutamyl transpeptidase (GGTP) and gamma glutamyl cysteine synthetase was determined in kidney tissue. Fasting led to a reduction of GSH from 3.21 +/- 0.54 to 1.25 +/- 0.20 mumol per gm in the group fed 10%. PIFA. Equivalent figures for the group fed 18% PIFA were 3.49 +/- 0.54 and 0.49 +/- 0.08, respectively. GGTP activity increased significantly after fasting but no differences were observed according to level of PIFA intake. The exaggerated reduction of GSH during fasting after a high PIFA intake may expose the animals to risk of cell damage induced by peroxides or other oxidating agents.

The effect of feeding 24 to 52-days-old male rats of the Wistar strain, with beans diet deficient in sulfur-containing amino acids or supplemented with 0.3% DL-methionine and two corn oil concentrations, 2% and 20% (g/kg/diet), on the glutathione content (GSH) in liver, and on the renal gamma glutamyl transpeptidase (GGTP) (E.C.2.3.2.2) activity was studied. Results indicated that rats fed the bean diet with 2% corn oil decreased significantly the liver GSH content and GGTP renal activity. Supplementation with 0.3% methionine and/or the 20% increment of the diet corn oil, significantly stimulated the liver GSH content and the transpeptidase activity in the kidney. It is postulated that the increase of polyunsaturated fatty acids, stimulated the GGTP activity as a way of increasing substrate bioavailability for synthesis de novo of liver GSH, necessary for the protection of the hydroperoxides formation, attributed to the increment of polyunsaturated acids at cellular level.