Luis Forga

Association of UCP3 gene -55C>T polymorphism and obesity in a Spanish population.

Background/Aims: The uncoupling protein 3 (UCP3) gene has been suggested as a possible determinant affecting obesity risk given its function in the regulation of energy metabolism. However, available genetic association studies have been inconsistent, which could be attributable to not considering individual lifestyle patterns, such as physical activity, a factor that affects UCP3 expression. The objective of this study was to assess the association between the UCP3 –55C>T polymorphism and the risk of obesity. Methods: Case-control study conducted in a sample of Spanish adults. 157 obese subjects (BMI ≧30) and 150 controls (BMI <25) participated in the study. UCP3 –55C>T polymorphism was identified by the polymerase chain reaction–restriction fragment length polymorphism methodology. Results: The odds ratio (OR) for obesity (95% confidence interval [CI]) according to the presence of UCP 3 gene –55C>T polymorphism (heterozygotes and homozygotes merged together), adjusting for age, sex, and recreational physical activity, was 0.61 (0.37–1.00), p = 0.05. Interestingly, this association was only manifest among those with higher recreational physical activity (OR: 0.46, 95% CI 0.21–0.99, p = 0.05) and not among those with lower physical activity (OR: 0.84, 95% CI 0.41–1.70, p = 0.84). Conclusion: UCP3 –55C>T polymorphism carriers have apparently a lower risk of obesity when taking into consideration recreational energy expenditure. Interestingly, this inverse beneficial association may only occur in people with a high level of physical activity.

CHO intake alters obesity risk associated with Pro12Ala polymorphism of PPARγ gene

Obesity in humans results from combined effects of genes, environment and lifestyles. A case-control study (obese vs. lean controls) was conducted to assess the possible association between obesity risk and the Pro12Ala polymorphism of the PPARg gene depending on the dietary intake.The study population comprised 313 Spanish subjects (66 men), which were gender and age-matched. Dietary intake was assessed through a validated food frequency questionnaire for epidemiological studies. Blood samples were taken for the extraction of genomic DNA from leukocytes in order to identify Pro12Ala gene polymorphism. This polymorphism was found similarly in obese (21.4%) and in controls (19.5%). Although the carbohydrate (CHO) intake was not statistically different among groups (p>0.05), the macronutrient distribution of the intake appeared as an effect modifier, since among those individuals with higher carbohydrate intake (>49% E), an increased obesity risk (ORa=5.12, p<0.04; IC95%:1.01-25.80) accompanied the occurrence of the polymorphism. In summary, despite that the studied gene polymorphism had not a direct effect on obesity risk, the results suggest that there are individual differences in the susceptibility to the dietary intake and confirm that gene-diet interactions may have a role in obesity prevalence and in the dietary management of obesity

A new dietary strategy for long-term treatment of the metabolic syndrome is compared with the American Heart Association (AHA) guidelines: the MEtabolic Syndrome REduction in NAvarra (RESMENA) project

The long-term effects of dietary strategies designed to combat the metabolic syndrome (MetS) remain unknown. The present study evaluated the effectiveness of a new dietary strategy based on macronutrient distribution, antioxidant capacity and meal frequency (MEtabolic Syndrome REduction in NAvarra (RESMENA) diet) for the treatment of the MetS when compared with the American Heart Association guidelines, used as Control. Subjects with the MetS (fifty-two men and forty-one women, age 49 (se 1) years, BMI 36·11 (se 0·5) kg/m²) were randomly assigned to one of two dietary groups. After a 2-month nutritional-learning intervention period, during which a nutritional assessment was made for the participants every 15 d, a 4-month self-control period began. No significant differences were found between the groups concerning anthropometry, but only the RESMENA group exhibited a significant decrease in body weight ( - 1·7%; P= 0·018), BMI ( - 1·7%; P= 0·019), waist circumference ( - 1·8%; P= 0·021), waist:hip ratio ( - 1·4%; P= 0·035) and android fat mass ( - 6·9%; P= 0·008). The RESMENA group exhibited a significant decrease in alanine aminotransferase and aspartate aminotransferase (AST) concentrations ( - 26·8%; P= 0·008 and - 14·0%; P= 0·018, respectively), while the Control group exhibited a significant increase in glucose (7·9%; P= 0·011), AST (11·3%; P= 0·045) and uric acid (9·0%; P< 0·001) concentrations. LDL-cholesterol (LDL-C) concentrations were increased (Control group: 34·4%; P< 0·001 and RESMENA group: 33·8%; P< 0·001), but interestingly so were the LDL-C:apoB ratio (Control group: 28·7%; P< 0·001, RESMENA group: 17·1%; P= 0·009) and HDL-cholesterol concentrations (Control group: 21·1%; P< 0·001, RESMENA group: 8·7; P= 0·001). Fibre was the dietary component that most contributed to the improvement of anthropometry, while body-weight loss explained changes in some biochemical markers. In conclusion, the RESMENA diet is a good long-term dietary treatment for the MetS.

The Risk of Obesity and the Trp64Arg Polymorphism of the β3-Adrenergic Receptor: Effect Modification by Age

Aim: To examine the association between the risk of obesity and the Trp64Arg polymorphism of the β3-adrenergic receptor gene. Methods: A case-control study was conducted. The case series encompassed 159 subjects with a body mass index >30 kg/m2 (obesity) and no other major diseases except for type 2 diabetes, and the controls were 154 healthy subjects with a body mass index <25 kg/m2. 313 Spanish subjects between 20 and 60 years of age were screened for the Trp64Arg mutation. Results: The prevalence of the Trp64Arg mutation was similar among cases (19.5%) and control subjects (16.2%). The association between the risk of obesity and the Trp64Arg mutation was estimated using multivariate logistic regression. A higher odds ratio of 3.84 (95% CI 1.33–11.12) for the mutation was found among younger individuals (20–35 years), while no increased risk was apparent among older participants (35–60 years). Moreover, when the model was adjusted for gender, age, and leisure-time physical activity, the product-term for interaction (effect modification) between age and the presence of the Trp64Arg mutation was statistically significant (likelihood ratio test p = 0.035). Conclusion: Individuals aged 20–35 years who are Trp64Arg carriers had a substantially higher risk of developing obesity, independent of their sex or leisure-time physical activity.

Thermogenesis induced by a high-carbohydrate meal in fasted lean and overweight young men: insulin, body fat, and sympathetic nervous system involvement

OBJECTIVEnThis dietary trial was designed to evaluate the effect of an experimental short-term fasting period followed by a high-carbohydrate meal on energy expenditure, thermogenesis, and sympathetic nervous system activity in normal (body mass index < 25 kg/m(2)) and overweight (body mass index > 27 kg/m(2)) men who were healthy, non-diabetic or with no other endocrine disease, non-smokers, not taking oral prescription medications, and with a stable body weight for the previous 3 mo.nnnMETHODSnFasting and fed energy expenditures and diet-induced thermogenesis were measured after a high-carbohydrate meal in seven overweight and six lean young male subjects by indirect calorimetry. Heart rate, urinary excretion of catecholamines, serum glucose, and insulin were also measured over the experimental fasting (7.5 h) and postprandial (4 h) periods.nnnRESULTSnAfter carbohydrate intake, overweight men showed a significantly higher energy production (kJ/kg of fat-free mass) than did lean individuals, and the diet-induced thermogenesis (percentage of energy intake) was positively correlated with body fat (kg), percentage of body fat, fat-free mass (kg), and fasting pre-meal serum insulin levels. Postprandial cumulative energy expenditure was directly associated with postprandial insulin response and with mean postprandial heart rate values. No significant differences in urinary catecholamines were found between lean and overweight men at basal conditions or during the study period.nnnCONCLUSIONSnOverweight individuals showed similar short-term sympathetic nervous system responses induced by an experimental fasting period. Although diet-induced thermogenesis after carbohydrate intake was not statistically different between lean and overweight men, the postprandial insulin response and body fat content seemed to be involved in sympathetic nervous system activity.

Effects of leptin resistance on acute fuel metabolism after a high carbohydrate load in lean and overweight young men.

Objective: Six lean (BMI = 20.8 ± 0.7) and seven overweight (BMI = 30.8 ± 1.7) young men (18–27 years old) were studied to investigate the acute effect of a high-carbohydrate meal on leptin levels and its relation to energy expenditure as well as to protein, carbohydrate and fat oxidation. Methods: Study participants were given a high-carbohydrate meal (17% as protein, 80% as carbohydrates and 3% as lipids) covering 40% of their estimated daily energy requirements. Serum leptin, insulin, glucose, free fatty acids and triglycerides levels were measured before meal intake and during the four postprandial hours. Furthermore, energy expenditure (EE), protein, carbohydrate and lipid oxidation were measured in fasted and fed conditions. Results: Fasting leptin was found to be positively correlated with circulating insulin concentrations (r = .748; p = 0.011) and body fat in kg (r = .827; p = 0.001). During the measured postprandial period no statistically significant changes were found in leptin levels as compared with pre-meal values in either lean or overweight men, nor differences in leptin changes between both groups. After load intake, carbohydrate oxidation was lower in overweight individuals (p < 0.05), while no significant differences were observed in protein oxidation. Cumulative lipid oxidation was found to be negatively associated with post-meal leptin values, being significantly lower in the overweight as compared with lean men (p < 0.05). This study demonstrates that the acute postprandial fuel substrate utilization is altered in overweight men with a lower carbohydrate oxidation and a strong inhibition of lipid oxidation, which could be attributed to some leptin resistance. Conclusion: These data also suggest that short-term meal-related metabolic responses may explain the long-term body adiposity if they are sustained over long intervals.