8-week Low-calorie Diet Research Articles

A Nutrigenomic Inflammation-Related PBMC-Based Approach to Predict the Weight-Loss Regain in Obese Subjects

Background: Long-term maintenance of a dietary-induced weight loss continues to be a major health problem and warrants research on innovative approaches to understand weight stability. We investigated the role of the proinflammatory status on weight changes in obese subjects receiving a low-calorie diet (LCD) and during the subsequent 6-month weight maintenance period. Methods: Eighty-four subjects (age: 34.2 ± 0.53 years; body mass index, BMI: 30.4 ± 1.8 kg/m²) followed an 8-week LCD intervention and were contacted again 6 months later. Body composition, circulating proinflammatory markers [tumor necrosis factor (TNF)α, interleukin-6, C-reactive protein and leptin] and mRNA levels of inflammation-related genes [TNFα and nuclear factor (NF) κBtranscription subunits] in peripheral blood mononuclear cells (PBMC) were evaluated. Results: The 6-month weight regain was predicted by high concentrations of TNFα at LCD completion (OR = 4.21, p = 0.036) along with the baseline amount of fat mass (OR = 7.23, p = 0.029). In addition, baseline leptin concentrations (p = 0.028) as well as mRNA levels of TNFα and NFκB subunits were higher at the end of the dietary intervention (p < 0.05) in PBMC of subjects who regained ≥10% of the dietary-induced weight loss. Conclusions: These findings demonstrate a role for the proinflammatory state and body adiposity in the prediction of weight-loss regain. This relationship could contribute to the design of more personalized nutritional treatments in obese patients and favor the weight maintenance process.

Expression of Two Inflammation-Related Genes (RIPK3 and RNF216) in Mononuclear Cells Is Associated with Weight-Loss Regain in Obese Subjects

Background/Aims: Nutrigenomics is providing molecular biomarkers concerning the assessment of diet-related diseases. We analyzed the expression of two interacting genes (RIPK3 and RNF216) in obese subjects receiving a low-calorie diet (LCD) and during the subsequent weight changes. Methods: Two groups of obese subjects (BMI 32.3 ± 5.5kg/m²; age 37.7 ± 7.1 years) were selected according to the 6-month weight-regain outcome after the weight-loss induced by an 8-week LCD (n = 12). Body composition and mRNA levels of RIPK3 and RNF216 in peripheral blood mononuclear cells (PBMC) were evaluated by qRT-PCR at three time-points (week 0, week 8 and week 32). Results: All subjects lost weight significantly (–5.8 ± 2.3%, p < 0.001) and were grouped depending on the successful weight-loss maintenance (weight-loss regain ≤10% or >10%). At baseline (week 0), no differences were observed in the mRNA levels between groups (p > 0.05). However, at the end of the LCD (week 8), association analysis revealed that higher mRNA levels in PBMC of RIPK3 and RNF216 were able to detect those individuals who are more prone to regain weight 6-month after the nutritional intervention (p < 0.05). Conclusions: Gene expression of RIPK3 and RNF216 in PBMC could identify those obese subjects, who will regain more weight after a successful initial weight loss. The mRNA levels of these genes could be suggested as nutrigenomic biomarkers for predicting the obesity treatment outcome.

CD36Gene Promoter Polymorphisms Are Associated With Low Density Lipoprotein-Cholesterol in Normal Twins and After a Low-Calorie Diet in Obese Subjects

Common polymorphisms of the CD36 fatty acid transporter gene have been associated with lipid metabolism and cardiovascular disease. Association of a CD36 promoter single nucleotide polymorphism genotype with anthropometry and serum lipids was investigated in normal subjects, and in obese subjects during an 8-week low calorie diet and 6-month weight-maintenance period. 2728 normal female Twins UK subjects (mean body mass index 24.8 +/- 4.4 kg/m2; age 47.3 +/- 12.5 y) and 183 obese male and female Spanish subjects (mean body mass index 30.6 +/- 3.0 kg/m2; age 35.0 +/- 5.0 y) were genotyped for the CD36-22674 T/C (rs2151916) promoter single nucleotide polymorphism. In the Twins UK full cohort, the C-allele was associated with lower low density lipoprotein-cholesterol (p = .02, N = 2396). No associations were found in the obese Spanish subjects at baseline, but 6 months after the end of the low-calorie diet, the C-allele was associated with lower total- (p = .03) and low density lipoprotein-cholesterol (p = .01) and higher high density lipoprotein-cholesterol (p = .01). Intake of saturated fatty acids was lower in carriers of the C-allele at baseline, but not significantly so (p = .11). However, 6 months after the end of the low-calorie diet, elements of the lipid profile were correlated with saturated fatty acid intake: total cholesterol r = .21, p = .060; low density lipoprotein-cholesterol: r = .25, p = .043; high density lipoprotein-cholesterol: r = -.26, p = .007. CD36 promoter SNP allele -22674C is therefore associated with lower serum low-density lipoprotein-cholesterol in normal female twins and with improved lipid profile during weight loss and maintenance in obese subjects.

Differential Expression of Oxidative Stress and Inflammation Related Genes in Peripheral Blood Mononuclear Cells in Response to a Low-Calorie Diet: A Nutrigenomics Study

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.

The − 11391G/APolymorphism of the Adiponectin Gene Promoter is Associated with Metabolic Syndrome Traits and the Outcome of an Energy-restricted Diet in Obese Subjects

Adiponectin is an adipose tissue-specific hormone that is commonly decreased in obese subjects. Furthermore, single-nucleotide polymorphisms (SNPs) of the adiponectin gene have been associated with metabolic phenotypes. The present study investigated whether the adiponectin gene promoter variant -11391 G/A (rs17300539) could predict the risk of developing traits characterizing the metabolic syndrome (MetS) and the impact of weight management. The -11391 G/A SNP was genotyped in 180 Spanish volunteers (BMI: 31.4+/-3.2 kg/m (2); age: 35+/-5 years). Clinical measurements were determined at baseline, following an 8-week low-calorie diet (LCD), and at 32 and 60 weeks. At baseline, the GG genotype was associated with higher HOMA-IR, insulin and triacylglyceride concentrations than other genotypes (p<0.05) and was also related with a higher risk of insulin resistance (OR: 2.437, p=0.025) and MetS clinical manifestations (OR: 3.236, p=0.003). Following the LCD, the increased risk in GG subjects compared with others disappeared (p>0.05). By 32 weeks after dietary therapy (n=84), GG carriers had recovered the risk of metabolic comorbidities (OR: 2.420, p=0.043). This risk was even more evident after 60 weeks (OR: 2.875, p=0.014). These data show an increased risk of insulin resistance and MetS complications in obese subjects of the -11391 GG genotype. The risk was markedly reduced during an energy-restricted diet, but was not sustained. Carriage of the A allele therefore confers protection from weight regain, and the effect is particularly evident 32-60 weeks after the dietary intervention, when improvement in GG subjects had disappeared.

Enhanced short-term improvement of insulin response to a low-caloric diet in obese carriers the Gly482Ser variant of the PGC-1α gene

Aim The Gly482Ser missense mutation of the transcriptional coactivator, peroxisome proliferator-activated receptor-γ coactivator-1α ( PGC-1α) has been involved in insulin function impairments, with conflicting results. The current study investigated the relationships of carrying this polymorphism with insulin resistance (IR) during a short-term weight-loss and the subsequent weight follow-up. Methods The Gly482Ser was genotyped in 180 Spanish volunteers [body mass index: 31.4 ± 3.2 kg/m 2; age: 35 ± 5 years]. Specific phenotypical measurements were determined at baseline, following an 8-week low-calorie diet (LCD) as well as after 6-month and 1-year of follow-up. Results At baseline the Ser482Ser genotype was associated with higher HOMA-IR and insulin concentrations than the other genotypes ( p < 0.05), which was accompanied by an increased higher risk of IR (OR: 2.97; 95% CI: 1.24–7.15). After following the LCD, such increased risk of insulin insensitivity in Ser482Ser carriers was toned down ( p > 0.05). This outcome was sustained after 6-month and 1-year of follow-up ( p > 0.05). Conclusions These data show an increased risk of IR in obese carrying the rs8192673 Ser482Ser genotype. This risk was markedly reduced by an energy-restricted diet, which was sustained 6 months and 1 year after the diet therapy. This observation allows identifying obese subjects who might personally profit most from an energy-restrictive treatment concerning insulin response and lead to more individualized prognostic and therapeutic decisions.

Obesity-related beliefs predict weight loss after an 8-week low-calorie diet

The objective of this study was to examine whether beliefs about the cause, consequences, time line, and control of obesity are predictors of the amount of weight loss after an 8-week, low-calorie diet consisting of meal replacements. Forty-eight women and 18 men, mean age=45.9 (range=23 to 73 years) years and body mass index between 30 and 50 participated in a weight-loss program. Beliefs were measured at baseline by the Obesity Cognition Questionnaire and by an eating behavior self-efficacy scale. Correlational and regression analyses were performed to examine whether beliefs predicted weight change. Changes in body mass index, waist circumference, and blood pressure were significant ( P<.001). Less weight reduction was associated with poor self-efficacy ( r=−0.34, P<.01) and the beliefs that obesity had a physical origin ( r=0.27, P=.04) and was not under behavioral control ( r=−0.25, P=.04). Self-efficacy remained a significant predictor in regression analysis. The results suggest that the outcome of dietary interventions may be improved when adjusting beliefs, especially self-efficacy.