EPA prevents fat mass expansion and metabolic disturbances in mice fed with a Western diet.

The impact of alpha linolenic acid (ALA), EPA, and DHA on obesity and metabolic complications was studied in mice fed a high-fat, high-sucrose (HF) diet. HF diets were supplemented with ALA, EPA, or DHA (1% w/w) and given to C57BL/6J mice for 16 weeks and to Ob/Ob mice for 6 weeks. In C57BL/6J mice, EPA reduced plasma cholesterol (-20%), limited fat mass accumulation (-23%) and adipose cell hypertrophy (-50%), and reduced plasma leptin concentration (-60%) compared with HF-fed mice. Furthermore, mice supplemented with EPA exhibited a higher insulin sensitivity (+24%) and glucose tolerance (+20%) compared with HF-fed mice. Similar effects were observed in EPA-supplemented Ob/Ob mice, although fat mass accumulation was not prevented. By contrast, in comparison with HF-fed mice, DHA did not prevent fat mass accumulation, increased plasma leptin concentration (+128%) in C57BL/6J mice, and did not improve glucose homeostasis in C57BL/6J and Ob/Ob mice. In 3T3-L1 adipocytes, DHA stimulated leptin expression whereas EPA induced adiponectin expression, suggesting that improved leptin/adiponectin balance may contribute to the protective effect of EPA. In conclusion, supplementation with EPA, but not ALA and DHA, could preserve glucose homeostasis in an obesogenic environment and limit fat mass accumulation in the early stage of weight gain.

Fat-soluble vitamin intestinal absorption: absorption sites in the intestine and interactions for absorption.

The interactions occurring at the intestinal level between the fat-soluble vitamins A, D, E and K (FSVs) are poorly documented. We first determined each FSV absorption profile along the duodenal-colonic axis of mouse intestine to clarify their respective absorption sites. We then investigated the interactions between FSVs during their uptake by Caco-2 cells. Our data show that vitamin A was mostly absorbed in the mouse proximal intestine, while vitamin D was absorbed in the median intestine, and vitamin E and K in the distal intestine. Significant competitive interactions for uptake were then elucidated among vitamin D, E and K, supporting the hypothesis of common absorption pathways. Vitamin A also significantly decreased the uptake of the other FSVs but, conversely, its uptake was not impaired by vitamins D and K and even promoted by vitamin E. These results should be taken into account, especially for supplement formulation, to optimise FSV absorption.

Optimizing separation conditions of 19 polycyclic aromatic hydrocarbons by cyclodextrin-modified capillary electrophoresis and applications to edible oils.

For the first time, the separation of 19 polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants in environmental and food samples by the United States Environmental Protection Agency (US-EPA) and the European Food Safety Authority was developed in cyclodextrin (CD)-modified capillary zone electrophoresis with laser-induced fluorescence detection (excitation wavelength: 325 nm). The use of a dual CD system, involving a mixture of one neutral CD and one anionic CD, enabled to reach unique selectivity. As solutes were separated based on their differential partitioning between the two CDs, the CD relative concentrations were investigated to optimize selectivity. Separation of 19 PAHs with enhanced resolutions as compared with previous studies on the 16 US-EPA PAHs and efficiencies superior to 1.5 × 10(5) were achieved in 15 min using 10mM sulfobutyl ether-ß-CD and 20mM methyl-ß-CD. The use of an internal standard (umbelliferone) with appropriate electrolyte and sample compositions, rinse sequences and sample vial material resulted in a significant improvement in method repeatability. Typical RSD variations for 6 successive experiments were between 0.8% and 1.7% for peak migration times and between 1.2% and 4.9% for normalized corrected peak areas. LOQs in the low µg/L range were obtained. For the first time in capillary electrophoresis, applications to real vegetable oil extracts were successfully carried out using the separation method developed here.

Olive oil and vitamin D synergistically prevent bone loss in mice.

As the Mediterranean diet (and particularly olive oil) has been associated with bone health, we investigated the impact of extra virgin oil as a source of polyphenols on bone metabolism. In that purpose sham-operated (SH) or ovariectomized (OVX) mice were subjected to refined or virgin olive oil. Two supplementary OVX groups were given either refined or virgin olive oil fortified with vitamin D3, to assess the possible synergistic effects with another liposoluble nutrient. After 30 days of exposure, bone mineral density and gene expression were evaluated. Consistent with previous data, ovariectomy was associated with increased bone turnover and led to impaired bone mass and micro-architecture. The expression of oxidative stress markers were enhanced as well. Virgin olive oil fortified with vitamin D3 prevented such changes in terms of both bone remodeling and bone mineral density. The expression of inflammation and oxidative stress mRNA was also lower in this group. Overall, our data suggest a protective impact of virgin olive oil as a source of polyphenols in addition to vitamin D3 on bone metabolism through improvement of oxidative stress and inflammation.

Optimized rapeseed oil enriched with healthy micronutrients: a relevant nutritional approach to prevent cardiovascular diseases. Results of the Optim'Oils randomized intervention trial.

Rapeseeds are naturally rich in cardioprotective micronutrients but refining leads to substantial losses or the production of undesirable compounds. The Optim'Oils European project proposed innovative refining conditions to produce an optimized rapeseed oil enriched in micronutrients and low in trans linolenic acid. We aimed to investigate cardioprotective properties of this Optimized oil. In a randomized, double-blind, controlled, cross-over study, 59 healthy normolipidaemic men consumed either Optimized or Standard rapeseed oils (20 g/d) and margarines (22 g/d) for 3 weeks. The Optimized oil reduced the trans FA concentration (p=0.009) and increased the contents of alpha-tocopherol (p=0.022) and coenzyme Q10 (p<0.001) in comparison with the Standard oil. Over the 3-week trial, Total-/HDL-cholesterol and LDL-/HDL-cholesterol were increased by 4% (p<0.05) with the Standard oil consumption whereas none of them rose with the Optimized rapeseed oil which increased the HDL-cholesterol and ApoA1 plasma content (+2%, NS and +3%, p<0.05 respectively). The effects observed on the plasma HDL-cholesterol levels (p=0.059), the Total-/HDL-cholesterol ratio (p=0.092), and on the ApoA1 concentrations (p=0.060) suggest an improvement of the cholesterol profile with the Optimized rapeseed oil. Finally, the Optimized oil reduced the plasma content of LDLox (-6%, NS), this effect being significantly different from the Standard oil (p=0.050). In conclusion, reasonable intake of an Optimized rapeseed oil resulting from innovative refining processes and enriched in cardioprotective micronutrients represent a relevant nutritional approach to prevent the risk of cardiovascular diseases by improving the cholesterol profile and reducing LDL oxidation.

n-3 PUFA status affects expression of genes involved in neuroenergetics differently in the fronto-parietal cortex compared to the CA1 area of the hippocampus: effect of rest and neuronal activation in the rat.

n-3 Polyunsaturated fatty acids (PUFA) support whole brain energy metabolism but their impact on neuroenergetics in specific brain areas and during neuronal activation is still poorly understood. We tested the effect of feeding rats as control, n-3 PUFA-deficient diet, or docosahexaenoic acid (DHA)-supplemented diet on the expression of key genes in fronto-parietal cortex and hippocampal neuroenergetics before and after neuronal stimulation (activated) by an enriched environment. Compared to control rats, n-3 deficiency specifically repressed GLUT1 gene expression in the fronto-parietal cortex in basal state and also during neuronal activation which specifically stimulated GLUT1. In contrast, in the CA1 area, n-3 deficiency improved the glutamatergic synapse function in both neuronal states (glutamate transporters, Na(+)/K(+) ATPase). DHA supplementation induced overexpression of genes encoding enzymes of the oxidative phosphorylation system and the F1F0 ATP synthase in the CA1 area. We conclude that n-3 deficiency repressed GLUT1 gene expression in the cerebral cortex, while DHA supplementation improved the mitochondrial ATP generation in the CA1 area of the hippocampus.