The nutritional composition of dietary intake could produce specific effects on metabolic variables such as mitochondrial oxidation, whose understanding could contribute to apply more individualized weight-lowering strategies. This study assessed the effects of four hypocaloric diets with high protein content or different food distribution on metabolic changes and mitochondrial oxidation accompanying weight loss. Thirty-five obese men (body mass index of 31.8 +/- 3.0 kg/m(2) and 38 +/- 7 years old) were randomly assigned to one of the four treatments (8 weeks): control diet (C-diet); legume diet (L-diet); fatty fish diet (FF-diet); or high-protein diet (HP-diet). Body composition, blood pressure, resting energy expenditure, mitochondrial oxidation, blood biomarkers, and dietary intake were assessed. The HP-diet and L-diet achieved the greater body weight reduction (-8.4 +/- 1.2% and -8.3 +/- 2.9%, respectively), as compared to the C-diet (-5.5 +/- 2.5%; P = .042). The high-density lipoprotein cholesterol concentrations were reduced in all dietary groups except for the FF-diet. Total and low-density lipoprotein cholesterol levels were significantly improved by the L-diet (P < .05), while the homeostatic model assessment index of insulin resistance value was significantly reduced in those men following the HP-diet. Mitochondrial oxidation was specifically activated by the HP-diet and L-diet at the end of the study. Interestingly, a lineal regression model explained about 25% (P = .029) of the mitochondrial oxidation variability as influenced by the diet changes once adjusted by resting energy expenditure. The specific consumption of legumes or high protein content within a hypocaloric diet could activate mitochondrial oxidation, which could involve additional benefits to those associated with the weight reduction.

Nutrigenomics is a new application of omics technologies in nutritional science. Nutrigenomics aims to identify molecular markers of diet-related diseases and mechanisms of interindividual variability in response to food. The aim of this study was to evaluate peripheral blood mononuclear cells (PBMC) as a model system and readily available source of RNA to discern gene expression signatures in relation to personalized therapy of obesity. PBMC were collected from obese men before and after an 8-week low-calorie diet (LCD) to lose weight. Changes in gene expression before and after the LCD were initially screened using a DNA-microarray platform and validated by qRT-PCR. Global gene expression analysis identified 385 differentially expressed transcripts after the LCD. Further analyses showed a decrease in some specific oxidative stress and inflammation genes. Interestingly, expression of these genes was directly related to body weight, while a lower IL8 gene expression was associated with higher fat mass decrease. Collectively, these observations suggest that PBMCs are a suitable RNA source and model system to perform nutrigenomics studies related to obesity and development of personalized dietary treatments. IL8 gene expression warrant further research as a putative novel biomarker of changes in body fat percentage in response to an LCD. 251

Legume intake could specifically protect against lipid peroxidation in addition to the effects associated to weight loss when included in hypocaloric diets. Thus, 30 obese subjects (age: 36 +/- 8 years and BMI: 32.0 +/- 5.3 kg/m(2)) were nutritionally treated by a 8-week energy restriction ( - 30% energy expenditure) with a legume enriched diet (4 days/week servings, [image omitted] ) or without legumes (control diet (CD), [image omitted] ). Body weight, circulating cholesterol, oxidized LDL (ox-LDL), malondialdehyde (MDA) and urinary 8-isoprostane F(2alpha) (8-iso-PGF(2alpha)) were measured at baseline and at endpoint. After the nutritional intervention, all obese subjects lost weight, specially those individuals who followed the legumes-enriched diet as compared to the CD ( - 7.7 +/- 3 vs. - 5.3 +/- 2.7%; p = 0.023), which was accompanied by marked decreases in total cholesterol levels (p < 0.001) and statistically significant diet-related reductions on plasma ox-LDL, plasma MDA and urinary 8-iso-PGF(2alpha) output. Therefore, a balanced diet with moderate caloric restriction including 4 day/week legume servings empowered the oxidative stress improvement related to weight loss through a reduction in lipid peroxidation as compared to a control hypocaloric diet.

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(dparrastur@unav.es) and Itziar Abete (iabetego@yahoo.es) have the same address than the corresponding author. Abbreviations:GI: glycemic index; BMI: body mass index; REE: resting energy expenditure; MFA: