The aim of this study was to determine the influence of an obesity treatment program on the gut microbiota and body weight of overweight adolescents. Thirty‐six adolescents (13–15 years), classified as overweight according to the International Obesity Task Force BMI criteria, were submitted to a calorie‐restricted diet (10–40%) and increased physical activity (15–23 kcal/kg body weight/week) program over 10 weeks. Gut bacterial groups were analyzed by quantitative real‐time PCR before and after the intervention. A group of subjects (n = 23) experienced >4.0 kg weight loss and showed significant BMI (P = 0.030) and BMI z‐score (P = 0.035) reductions after the intervention, while the other group (n = 13) showed <2.0 kg weight loss. No significant differences in dietary intake were found between both groups. In the whole adolescent population, the intervention led to increased Bacteroides fragilis group (P = 0.001) and Lactobacillus group (P = 0.030) counts, and to decreased Clostridium coccoides group (P = 0.028), Bifidobacterium longum (P = 0.031), and Bifidobacterium adolescentis (P = 0.044) counts. In the high weight–loss group, B. fragilis group and Lactobacillus group counts also increased (P = 0.001 and P = 0.007, respectively), whereas C. coccoides group and B. longum counts decreased (P = 0.001 and P = 0.044, respectively) after the intervention. Total bacteria, B. fragilis group and Clostridium leptum group, and Bifidobacterium catenulatum group counts were significantly higher (P < 0.001–0.036) while levels of C. coccoides group, Lactobacillus group, Bifidobacterium, Bifidobacterium breve, and Bifidobacterium bifidum were significantly lower (P < 0.001–0.008) in the high weight–loss group than in the low weight–loss group before and after the intervention. These findings indicate that calorie restriction and physical activity have an impact on gut microbiota composition related to body weight loss, which also seem to be influenced by the individual's microbiota.

High rates of childhood obesity require integral treatment with lifestyle modifications that achieve weight loss. We evaluated a lifestyle intervention on nutrient adequacy and diet quality in children and adolescents with abdominal obesity. A randomized controlled trial was performed on 107 participants, assigned either to a usual care group or to an intensive care group that followed a moderate hypocaloric Mediterranean diet and received nutritional education. Intake adequacy was evaluated using Dietary Reference Intakes and diet quality through the Diet Quality Index for Adolescents (DQI-A), the Healthy Lifestyle Diet-Index (HLD-I) and the Mediterranean Diet Quality Index (KIDMED). Both groups achieved a significant reduction in BMI standard deviation score (BMI-SDS), glucose and total cholesterol levels. Intake of Calcium, Iodine and vitamin D were higher in the intensive care group, with enhanced compliance with recommendations. Higher dietary scores were associated with lower micronutrient inadequacy. DQI-A and HLD-I were significantly higher in the intensive care group vs. usual care group after the treatment. In conclusion, we observed that an intensive lifestyle intervention was able to reduce BMI-SDS in children with abdominal obesity. Furthermore, participants significantly improved dietary indices getting closer to the nutritional recommendations. Therefore, these diet quality indices could be a valid indicator to evaluate micronutrient adequacy.

The rs9939609 polymorphism of the fat mass and obesity-associated (FTO) gene has been widely associated with childhood obesity in several European cohorts. This association appears to be dependent on dietary macronutrients. Therefore, the aim of the present study was to evaluate whether dietary fatty acid intake distribution could interact with this FTO genetic variation and obesity in a Spanish case–control study of children and adolescents. A total of 354 Spanish children and adolescents aged 6–18 years (49 % males) were genotyped for the rs9939609 variant of the FTO gene. Anthropometric parameters were taken and energy intake was measured. We observed an interaction between the consumption of SFA (percentage of total energy) and PUFA:SFA ratio and obesity risk linked to the rs9939609 SNP of the FTO gene. In the study population of the present study, the risk allele carriers consuming more than 12·6 % SFA (of total energy) had an increased obesity risk compared with TT carriers. In a similar way, A allele carriers with an intake ratio lower than 0·43 PUFA:SFA presented a higher obesity risk than TT subjects. In summary, the present study reports for the first time the influence of dietary fatty acid distribution on the effect of the rs9939609 polymorphism of the FTO gene on children and adolescents' obesity risk.

Telomeres are biomarkers of biological aging. Shorter telomeres have been associated with increased adiposity in adults. However, this relationship remains unclear in children and adolescents. To evaluate the association between telomere length (TL) and adiposity markers in overweight/obese adolescents after an intensive program. We hypothesize that greater TL at baseline would predict a better response to a weight loss treatment. The EVASYON is a multidisciplinary treatment program for adolescents with overweight and obesity that is aimed at applying the intervention to all possibly involved areas of the individual, such as dietary habits, physical activity and cognitive and psychological profiles. Seventy-four participants (36 males, 38 females, 12–16 yr) were enrolled in the intervention program: 2 months of an energy-restricted diet and a follow-up period (6 months). TL was measured by quantitative real-time polymerase chain reaction at baseline and after 2 months; meanwhile, anthropometric variables were also assessed after 6 months of follow-up. TL lengthened in participants during the intensive period (+1.9±1.0, p<0.001) being greater in overweight/obese adolescents with the shortest telomeres at baseline (r = −0.962, p<0.001). Multivariable linear regression analysis showed that higher baseline TL significantly predicted a higher decrease in body weight (B = −1.53, p = 0.005; B = −2.25, p = 0.047) and in standard deviation score for body mass index (BMI-SDS) (B = −0.22, p = 0.010; B = −0.47, p = 0.005) after the intensive and extensive period treatment respectively, in boys. Our study shows that a weight loss intervention is accompanied by a significant increase in TL in overweight/obese adolescents. Moreover, we suggest that initial longer TL could be a potential predictor for a better weight loss response.

AIMS: Multiple genes are likely to be involved in obesity and these genes may interact with environmental factors to influence obesity risk. Our aim was to explore the synergistic contribution of the two polymorphisms: Pro12Ala of the PPARγ2 gene and Trp64Arg of the ADRβ3 gene to obesity risk in a Spanish children and adolescent population. METHODS: We designed a sex- and age-matched case–control study. Participants were 185 obese and 185 control children (aged 5–18 y) from the Navarra region, recruited through Departments of Pediatrics (Hospital Virgen del Camino, Navarra University Clinic and several Primary Health Centers). The obesity criterion (case definition) was BMI above the 97th percentile according to Spanish BMI reference data for age and gender. Anthropometric parameters were measured by standard protocols. The genotype was assessed by PCR-RFLP after digestion with BstUI for PPARγ2 mutation and BstNI for ADRβ3 variants. Face-to-face interviews were conducted to assess the physical activity. Using a validated physical activity questionnaire, we computed an activity metabolic equivalent index (METs h/week), which represents the physical exercise during the week for each participant. Statistical analysis was performed by conditional logistic regression, taking into account the matching between cases and controls. RESULTS: Carriers of the polymorphism Pro12Ala of the PPARγ2 gene had a significantly higher obesity risk than noncarriers (odds ratio (OR)=2.18, 95% CI=1.09–4.36) when we adjusted for sex, age and physical activity. Moreover, the risk of obesity was higher (OR=2.59, 95% CI=1.17–5.34) when family history of obesity was also taken into account in the model. The OR for obesity linked to both polymorphisms (PPARγ2 and ADRβ3) was 5.30 (95% CI=1.08–25.97) when we adjusted for sex, age and physical activity. After adjustment for family history of obesity, the OR for carriers of both polymorphisms was 19.5 (95% CI=2.43–146.8). CONCLUSIONS: A synergistic effect between polymorphism Pro12Ala of the PPARγ2 gene and Trp64Arg of the ADRβ3 gene for obesity risk was found in a case–control study including children and adolescents.