Benefits of Fish Oil Consumption over Other Sources of Lipids on Metabolic Parameters in Obese Rats.

This study evaluated the effect of the consumption of different levels and sources of lipids on metabolic parameters of Wistar rats. Animals were fed with high-fat diet (HFD) containing 20% of lard for 12 weeks to cause metabolic obesity. Subsequently, the animals were divided into six groups and were fed diets with lipid concentrations of 5% or 20% of lard (LD), soybean oil (SO) or fish oil (FO), for 4 weeks. Data were submitted to analysis of variance (two-way) followed by Tukey post hoc test (p < 0.05). The groups that consumed FO showed less weight gain and lower serum levels of triacylglycerol (TAG), total cholesterol and fractions, aspartate aminotransferase (AST) activity, atherogenic index, less amount of fat in the carcass, decreased Lee index and lower total leukocyte counting (p < 0.05). These same parameters were higher in LD treatment (p < 0.05). In the concentration of 20%, carcass fat content, blood glucose levels, as well as alanine aminotransferase (ALT) and gamma glutamyl transferase (GGT) decreased in FO groups (p < 0.05). The SO group had intermediate results regarding the other two treatments (FO and LD). We concluded that fish oil intake was able to modulate positively the metabolic changes resulting from HFD.

Protective effect of soybean oil- or fish oil-rich diets on allergic airway inflammation.

BACKGROUND: The increased prevalence of asthma and allergic diseases in westernized societies has been associated with increased intake of diets rich in n-6 fatty acids (FAs) and poor in n-3 FAs. This study aimed to analyze the prophylactic effects of treatment with a soybean oil-rich diet (rich in n-6) or fish oil (rich in n-3) in an allergic airway inflammation model on lung inflammation score, leukocyte migration, T-helper cell (Th)-2 (interleukin [IL]-4, IL-5) and Th1 (interferon [IFN]-γ, tumor necrosis factor-α) cytokines, lipoxin A4, nitric oxide, bradykinin, and corticosterone levels in bronchoalveolar lavage (BAL) or lungs. METHODS: Male Wistar rats fed with soybean oil- or fish oil-rich diet or standard rat chow were sensitized twice with ovalbumin-alumen and challenged twice with ovalbumin aerosol. The BAL and lungs were examined 24 hours later. RESULTS: Both diets, rich in n-6 or n-3 FAs, impaired the allergic lung inflammation and reduced leukocyte migration, eosinophil and neutrophil percentages, and IL-4/IL-5/bradykinin levels in BAL and/or lungs, as well as increased the nitric oxide levels in BAL. The soybean oil-rich diet additionally increased the levels of lipoxin A4 and corticosterone in the lungs. CONCLUSION: Data presented demonstrated that the n-6 FA-rich diet had protective effect upon allergic airway inflammation and was as anti-inflammatory as the n-3 FA-rich diet, although through different mechanisms, suggesting that both diets could be considered as complementary therapy or a prophylactic alternative for allergic airway inflammation.

Toxicological aspects of trans fat consumption over two sequential generations of rats: Oxidative damage and preference for amphetamine.

Chronic consumption of processed food causes structural changes in membrane phospholipids, affecting brain neurotransmission. Here we evaluated noxious influences of dietary fats over two generations of rats on amphetamine (AMPH)-conditioned place preference (CPP). Female rats received soybean oil (SO, rich in n-6 fatty acids (FA)), fish oil (FO, rich in n-3 FA) and hydrogenated vegetable fat (HVF, rich in trans fatty acids (TFA)) for two successive generations. Male pups from the 2nd generation were maintained on the same supplementation until 41 days of age, when they were conditioned with AMPH in CPP. While the FO group showed higher incorporation of n-3 polyunsaturated-FA (PUFA) in cortex/hippocampus, the HVF group showed TFA incorporation in these same brain areas. The SO and HVF groups showed AMPH-preference and anxiety-like symptoms during abstinence. Higher levels of protein carbonyl (PC) and lower levels of non-protein thiols (NPSH) were observed in cortex/hippocampus of the HVF group, indicating antioxidant defense system impairment. In contrast, the FO group showed no drug-preference and lower PC levels in cortex. Cortical PC was positively correlated with n-6/n-3 PUFA ratio, locomotion and anxiety-like behavior, and hippocampal PC was positively correlated with AMPH-preference, reinforcing connections between oxidative damage and AMPH-induced preference/abstinence behaviors. As brain incorporation of trans and n-6 PUFA modifies its physiological functions, it may facilitate drug addiction.

Dietary polyunsaturated fatty acid intake during late pregnancy affects fatty acid composition of mature breast milk.

OBJECTIVE: The aim of this study was to investigate how maternal polyunsaturated fatty acid intake at different periods during pregnancy affects the composition of polyunsaturated fatty acids in mature human milk. METHODS: A prospective study was conducted involving 45 pregnant women, aged between 18 and 35 y, who had full-term pregnancies and practiced exclusive or predominant breast-feeding. Mature breast milk samples were collected after the 5th postpartum week by manual expression; fatty acid composition was determined by gas chromatography. Fatty acid intake during pregnancy and puerperium was estimated through multiple 24-h dietary recalls. Linear regression models, adjusted by postpartum body mass index and deattenuated, were used to determine associations between estimated fatty acids in maternal diet during each trimester of pregnancy and fatty acid content in mature human milk. RESULTS: A positive association was identified between maternal intake of eicosapentaenoic acid (ß, 1.873; 95% confidence interval [CI], 0.545, 3.203) and docosahexaenoic acid (ß, 0.464; 95% CI, 0.212-0.714) during the third trimester of pregnancy, as well as the maternal dietary ω-3 to ω-6 ratio (ß, 0.093; 95% CI, 0.016-0.170) during the second and third trimesters and postpartum period, with these fatty acids content in mature breast milk. CONCLUSIONS: The maternal dietary docosahexaenoic acid and eicosapentaenoic acid content during late pregnancy may affect the fatty acid composition of mature breast milk. Additionally, the maternal dietary intake of ω-3 to ω-6 fatty acid ratio, during late pregnancy and the postpartum period, can affect the polyunsaturated fatty acid composition of breast milk.

Ácido graxo W-6 na etiologia do câncer de cólon e reto / W-6 fatty acid and colorectal cancer

No mundo, os tumores malignos que acometem cólon e reto a cada ano somam cerca de 945 mil novos casos, sendo a terceira causa mais comum de câncer no mundo e a segunda em países desenvolvidos. Entre alguns fatores de risco para o câncer colorretal, incluem-se dieta com alto conteúdo de gordura, além das doenças inflamatórias do cólon como: retocolite ulcerativa crônica e Doença de Cronh. Ao menos um terço de todos os casos de câncer em humanos pode ser associado com a dieta e influenciado pelo estilo de vida. Uma mudança drástica no perfil do consumo de ácidos graxos poli-insaturados, em um curto período de tempo, pode estar relacionada a alterações nos padrões genéticos estabelecidos durante a evolução humana. A produção excessiva de eicosanoides derivados do ácido araquidônico, que tem como precursor o ácido linoleico, tem sido envolvida em muitos distúrbios inflamatórios e autoimunes, inclusive no processo de carcinogênese. Este trabalho é uma revisão bibliográfica, de artigos publicados nos últimos 12 anos, de fontes de revistas indexadas em bibliotecas virtuais (PubMed, Scielo,Medline, Bireme), com o objetivo de discutir a associação entre o ácido graxo w-6 na promoção do câncer colorretal.