Correlates of dietary energy misreporting among European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study.

This study examined the correlates of dietary energy under-reporting (UR) and over-reporting (OV) in European adolescents. Two self-administered computerised 24-h dietary recalls and physical activity data using accelerometry were collected from 1512 adolescents aged 12·5-17·5 years from eight European countries. Objective measurements of height and weight were obtained. BMI was categorised according to Cole/International Obesity Task Force (IOTF) cut-off points. Diet-related attitudes were assessed via self-administered questionnaires. Reported energy intake (EI) was compared with predicted total energy expenditure to identify UR and OV using individual physical activity objective measures. Associations between misreporting and covariates were examined by multilevel logistic regression analyses. Among all, 33·3 % of the adolescents were UR and 15·6 % were OV when considering mean EI. Overweight (OR 3·25; 95 % CI 2·01, 5·27) and obese (OR 4·31; 95 % CI 1·92, 9·65) adolescents had higher odds for UR, whereas underweight individuals were more likely to over-report (OR 1·67; 95 % CI 1·01, 2·76). Being content with their own figures (OR 0·61; 95 % CI 0·41, 0·89) decreased the odds for UR, whereas frequently skipping breakfast (OR 2·14; 95 % CI 1·53, 2·99) was linked with higher odds for UR. Those being worried about gaining weight (OR 0·55; 95 % CI 0·33, 0·92) were less likely to OV. Weight status and psychosocial weight-related factors were found to be the major correlates of misreporting. Misreporting may reflect socially desirable answers and low ability to report own dietary intakes, but also may reflect real under-eating in an attempt to lose weight or real over-eating to reflect higher intakes due to growth spurts. Factors influencing misreporting should be identified in youths to clarify or better understand diet-disease associations.

European adolescent ready-to-eat-cereal (RTEC) consumers have a healthier dietary intake and body composition compared with non-RTEC consumers.

PURPOSE: This study aims to analyse the association of European adolescents' ready-to-eat-cereal (RTEC) consumption frequency with their dietary intake by applying the concept of diet quality index and nutritional status. METHODS: From the multi-centre European HELENA study, relevant data were available in 1,215 adolescents (12.5-17.5 years). RTEC consumption was identified from a food frequency questionnaire. A diet quality index, daily nutrient intakes and daily milk/yoghurt and fruit intake were calculated from two 24-h dietary recalls. BMI, waist and hip circumference and body fat were measured for body composition. Cross-sectional regression analyses were adjusted for sex, age, socio-economic status, city and breakfast skipping. Differences in sub-regions within Europe were explored. RESULTS: RTEC consumers showed a more favourable daily micronutrient intake (vitamin B2, B5, B7, D, calcium, phosphorus and potassium), a better diet quality index, more frequent fruit (57 vs. 51%) and milk/yoghurt consumption (81.2 vs. 56%) and less breakfast skipping (25.1 vs. 36.7%). No differences in energy and macronutrient intake were observed. Daily RTEC consumers were 57% less likely to be overweight than RTEC non-consumers but did not differ in glucose and lipid status (N = 387). CONCLUSION: This is the first comprehensive pan-European survey elucidating socio-demographic determinants of European adolescents' RTEC consumption and indicating better dietary habits in RTEC consumers. The improved dietary profile was reflected in a more beneficial body composition. Our results have also shown the advantage of using an all-integrating diet quality index by capturing the diet complexity.

The relationship between cotinine concentrations and inflammatory markers among highly secondhand smoke exposed non-smoking adolescents.

BACKGROUND: Secondhand smoke (SHS) exposure is a risk factor of respiratory, cardiovascular and inflammatory diseases, however its association with inflammatory markers among highly SHS exposed adolescents has not yet been explored. METHODS: Participants included in this study were a subset of 68 non-smoking adolescents, aged 12.5-17.5 from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study, recruited from Crete Greece. Smoking and SHS exposure was assessed via serum cotinine concentrations. Cytokines (Interleukin-1ß, 2, 4, 5 and 6, tumor necrosis factor-α, interferon-γ, tumor growth factor-ß1), immunoglobulins IgG, IgA, IgM, complement factors C3, C4, high sensitivity C-reactive protein, and endothelial inflammatory markers [soluble E-selectin, soluble L-selectin, soluble intercellular adhesion molecules (sICAM-1) and soluble vascular cell adhesion molecules-1 (sVCAM-1)] were assessed. Inflammatory markers in the lower 25th percentile and upper 75th percentile groups of cotinine levels were compared and multivariate linear regression analysis was performed controlling for age, sex and BMI. RESULTS: Cotinine concentrations were notably elevated (geometric mean 0.82ng/ml, 95%CI 0.62-1.07) in this study population. A significant decrease in IL-4 (130.09 vs. 25.77pg/ml, p=0.014) and IL-6 (19.52 vs. 5.52pg/ml, p=0.008) concentrations between the upper 75th percentile cotinine level group and lower 25th percentile cotinine level group was observed. In a multivariate linear regression analysis, cotinine concentrations had a weak inverse association with IL-4 and IL-6 (p=0.028 and p=0.06) which was not statistically significant when adjusted for multiple comparisons (modified Bonferroni, p>0.016). No differences in the other variables was noted. CONCLUSIONS: Among highly SHS exposed adolescents, cotinine levels had weak inverse association with IL-4 and IL-6, which did not achieve statistical significance. However, our results potentially indicate an immunosuppressive role of SHS. Further research is warranted to explore this hypothesis.

Dietary and lifestyle quality indices with/without physical activity and markers of insulin resistance in European adolescents: the HELENA study.

Emerging data indicate that higher levels of insulin resistance (IR) are common among children and adolescents and are related to cardiometabolic risk; therefore, IR requires consideration early in life. In addition, there is a lack of conclusive evidence regarding the role of dietary nutrients on IR. The Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study (HELENA-CSS) was conducted in European adolescents aged 12·5­17·5 years. A total of 637 participants with valid homeostasis model assessment (HOMA) index data and who completed at least a 2 d 24 h dietary recall were included in the study (60% of the total HELENA-CSS sample). There were two dietary indices calculated, with the only difference between them being the inclusion or not of physical activity (PA). Markers of IR such as HOMA and the quantitative insulin sensitivity check index (QUICKI) were calculated. Pubertal status, BMI and cardiorespiratory fitness (CRF) were measured as potential confounders. The dietary index including PA was inversely associated with HOMA and directly with the QUICKI in females, but not in males, after adjusting for pubertal status, centre, BMI and CRF. In conclusion, the present study indicates that considering PA as part of the dietary index is of relevance as the resulted index is inversely related to IR independently of potential confounders including CRF. Overall, these findings suggest that intervention studies aimed at preventing IR in young people should focus on increasing the quality of the diet and also on including an optimal PA level in healthy adolescents.

North-south gradients in plasma concentrations of B-vitamins and other components of one-carbon metabolism in Western Europe: results from the European Prospective Investigation into Cancer and Nutrition (EPIC) Study.

Different lifestyle patterns across Europe may influence plasma concentrations of B-vitamins and one-carbon metabolites and their relation to chronic disease. Comparison of published data on one-carbon metabolites in Western European regions is difficult due to differences in sampling procedures and analytical methods between studies. The present study aimed, to compare plasma concentrations of one-carbon metabolites in Western European regions with one laboratory performing all biochemical analyses. We performed the present study in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort among 5446 presumptively healthy individuals. Quantile regression was used to compare sex-specific median concentrations between Northern (Denmark and Sweden), Central (France, Germany, The Netherlands and United Kingdom) and Southern (Greece, Spain and Italy) European regions. The lowest folate concentrations were observed in Northern Europe (men, 10·4 nmol/l; women, 10·7 nmol/l) and highest concentrations in Central Europe. Cobalamin concentrations were slightly higher in Northern Europe (men, 330 pmol/l; women, 352 pmol/l) compared with Central and Southern Europe, but did not show a clear north-south gradient. Vitamin B2 concentrations were highest in Northern Europe (men, 22·2 nmol/l; women, 26·0 nmol/l) and decreased towards Southern Europe (P trend< 0·001). Vitamin B(6) concentrations were highest in Central Europe in men (77·3 nmol/l) and highest in the North among women (70·4 nmol/l), with decreasing concentrations towards Southern Europe in women (P trend< 0·001). In men, concentrations of serine, glycine and sarcosine increased from the north to south. In women, sarcosine increased from Northern to Southern Europe. These findings may provide relevant information for the study of regional differences of chronic disease incidence in association with lifestyle.

Food intake of European adolescents in the light of different food-based dietary guidelines: results of the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study.

OBJECTIVE: Since inadequate food consumption patterns during adolescence are not only linked with the occurrence of obesity in youth but also with the subsequent risk of developing diseases in adulthood, the establishment and maintenance of a healthy diet early in life is of great public health importance. Therefore, the aim of the present study was to describe and evaluate the food consumption of a well-characterized sample of European adolescents against food-based dietary guidelines for the first time. DESIGN: The HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study is a cross-sectional study, whose main objective was to obtain comparable data on a variety of nutritional and health-related parameters in adolescents aged 12·5-17·5 years. SETTING: Ten cities in Europe. SUBJECTS: The initial sample consisted of more than 3000 European adolescents. Among these, 1593 adolescents (54 % female) had sufficient and plausible dietary data on energy and food intakes from two 24 h recalls using the HELENA-DIAT software. RESULTS: Food intake of adolescents in Europe is not optimal compared with the two food-based dietary guidelines, Optimized Mixed Diet and Food Guide Pyramid, examined in this study. Adolescents eat half of the recommended amount of fruit and vegetables and less than two-thirds of the recommended amount of milk (and milk products), but consume much more meat (and meat products), fats and sweets than recommended. However, median total energy intake may be estimated to be nearly in line with the recommendations. CONCLUSION: The results urge the need to improve the dietary habits of adolescents in order to maintain health in later life.

Can differences in physical activity by socio-economic status in European adolescents be explained by differences in psychosocial correlates? A mediation analysis within the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study.

OBJECTIVE: Socio-economic status (SES) has been positively associated with physical activity (PA) levels in adolescents. In order to tackle these social inequalities, information is needed about the underlying mechanisms of this association. The present study aimed to investigate the potential mediating role of psychosocial correlates of PA on the relationship between SES and PA in European adolescents. DESIGN: Cross-sectional study testing the mediating role of psychosocial correlates in the SES-PA association using the product-of-coefficients test of MacKinnon. SETTING: Ten European cities in nine different countries, the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study. SUBJECTS: Adolescents (n 2780) aged 12·5-17·49 years self-reported on PA (moderate-to-vigorous intensity PA and total PA), SES indicators (education of the mother and Family Affluence Scale) and psychosocial correlates of PA (stage of change, attitudes, awareness, modelling, social support, self-efficacy, benefits, barriers and environmental correlates). RESULTS: SES (Family Affluence Scale) was significantly associated with moderate-to-vigorous intensity PA. According to single-mediator models, this association was significantly mediated by stage of change (t = 3·6, P ≤ 0·001), awareness (t = 2·7, 0·001 < P ≤ 0·01), modelling (t = 4·8, P ≤ 0·001), self-efficacy (t = 2·5, 0·01

Nutritional knowledge in European adolescents: results from the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study.

OBJECTIVE: To build up sufficient knowledge of a 'healthy diet'. Here, we report on the assessment of nutritional knowledge using a uniform method in a large sample of adolescents across Europe. DESIGN: A cross-sectional study. SETTING: The European multicentre HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study conducted in 2006-2007 in ten cities in Austria, Belgium, France, Germany, Greece (one inland and one island city), Hungary, Italy, Spain and Sweden. SUBJECTS: A total of 3546 adolescents (aged 12·5-17·5 years) completed a validated nutritional knowledge test (NKT). Socio-economic variables and anthropometric data were considered as potential confounders. RESULTS: NKT scores increased with age and girls had higher scores compared with boys (62% v. 59%; P < 0·0001). Scores were approximately 10% lower in 'immigrant' adolescents or in adolescents with 'immigrant' mothers. Misconceptions with respect to the sugar content in food or in beverages were found. Overall, there was no correlation between BMI values and NKT scores. After categorization according to BMI, scores increased significantly with BMI group only in boys. These differences disappeared after controlling for socio-economic status (SES). Smoking status and educational level of the mother influenced the NKT scores significantly in boys, as well as the educational levels of both parents in girls. CONCLUSIONS: Nutritional knowledge was modest in our sample. Interventions should be focused on the lower SES segments of the population. They should be initiated at a younger age and should be combined with environmental prevention (e.g. healthy meals in school canteens).

Development of a Genetic Risk Score to predict the risk of overweight and obesity in European adolescents from the HELENA study.

Obesity is the result of interactions between genes and environmental factors. Since monogenic etiology is only known in some obesity-related genes, a genetic risk score (GRS) could be useful to determine the genetic predisposition to obesity. Therefore, the aim of our study was to build a GRS able to predict genetic predisposition to overweight and obesity in European adolescents. A total of 1069 adolescents (51.3% female), aged 11-19 years participating in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) cross-sectional study were genotyped. The sample was divided in non-overweight (non-OW) and overweight/obesity (OW/OB). From 611 single nucleotide polymorphisms (SNP) available, a first screening of 104 SNPs univariately associated with obesity (p < 0.20) was established selecting 21 significant SNPs (p < 0.05) in the multivariate model. Unweighted GRS (uGRS) was calculated by summing the number of risk alleles and weighted GRS (wGRS) by multiplying the risk alleles to each estimated coefficient. The area under curve (AUC) was calculated in uGRS (0.723) and wGRS (0.734) using tenfold internal cross-validation. Both uGRS and wGRS were significantly associated with body mass index (BMI) (p < .001). Both GRSs could potentially be considered as useful genetic tools to evaluate individual's predisposition to overweight/obesity in European adolescents.

Passive smoking alters circulating naïve/memory lymphocyte T-cell subpopulations in children.

While it has been indicated that exposure to second-hand smoke (SHS) can cause a local in vivo response, limited evidence exists on its possible systemic effects from population-based levels of exposure. We investigated into a possible systemic response in the immune parameters and lymphocyte subsets, i.e. B cell (CD19+), T cell (CD4+CD45RO+, CD4+CD45RA+, CD3+CD45RO+, CD3+CD45RA+) and natural killer (CD3+CD16CD56+) lymphocyte subsets relative to exposure to SHS. Blood was drawn from healthy, verified non-smoker, adolescent subjects (n = 68, mean age 14.2) and analysed for cotinine, antioxidants and lymphocyte immunophenotyping. SHS exposure was assessed using serum cotinine. Biomarker quantified exposure to SHS was correlated with a linear dose-response reduction in the percentages of memory CD4+CD45RO+ (p = 0.005) and CD3+CD45RO+ T-cell subsets (p = 0.005 and p = 0.003, respectively) and a linear increase in the percentage of naïve CD4+CD45RA+ and CD3+CD45RA+ T-cell subsets (p = 0.006 and p = 0.003, respectively). Additionally, higher exposure to SHS was associated with a higher CD4+CD45RA+ count (532 vs. 409 cells/ml, p = 0.017). Moreover, after controlling for age, gender, body mass index and plasma antioxidants, SHS exposure was found to be associated with the percentage of circulating naïve and memory CD4+ and CD3+ T-cell subpopulations, as revealed through a linear regression analysis. These findings indicate a systemic immunological response in healthy adolescents exposed to population-based levels of SHS exposure and imply an additional biological pathway for the interaction between exposure to SHS and its adverse effects on human health.

The nutritional requirements of infants. Towards EU alignment of reference values: the EURRECA network.

This paper presents a review of the current knowledge regarding the macro- and micronutrient requirements of infants and discusses issues related to these requirements during the first year of life. The paper also reviews the current reference values used in European countries and the methodological approaches used to derive them by a sample of seven European and international authoritative committees from which background scientific reports are available. Throughout the paper, the main issues contributing to disparities in micronutrient reference values for infants are highlighted. The identification of these issues in relation to the specific physiological aspects of infants is important for informing future initiatives aimed at providing standardized approaches to overcome variability of micronutrient reference values across Europe for this age group.

Reliability and validity of a healthy diet determinants questionnaire for adolescents.

OBJECTIVE: To describe the development of a short questionnaire including a wide range of personal, social and environmental constructs in relation to a healthy diet in an adolescent population. DESIGN: The questionnaire was developed based on the literature, past experiences and feedback from a small pilot study (n 10). Test and retest (2 weeks later) of the questionnaire was done to investigate test-retest reliability. Data of four non-consecutive 24 h recalls were collected to investigate the predictive validity with food (fruit, vegetables, milk, snacks, soft drinks), nutrient (fibre, ascorbic acid, Ca, percentage energy from fat) and energy intakes. SETTING: At home, in the presence of a student. SUBJECTS: Convenience sample of fifty-five Belgian-Flemish adolescents approached by university students for course credits. RESULTS: Test-retest correlations of the constructs ranged between 0.51 and 0.78. Eleven of the eighteen final constructs were significantly associated with one or more of the five selected food items, all in the expected direction. Most significant associations with the food items were found for taste, perceived peers' behaviour and availability of soft drinks at home. Fresh fruit and soft drinks were correlated with most constructs (seven) followed by snacks (five). Concerning energy and the selected nutrient variables, the findings were less clear. CONCLUSIONS: The results are promising: the test-retest stability was moderate to good; most of the psychosocial constructs were significantly associated with one or more of the selected dietary variables. Future work in a larger sample of European adolescents is warranted.

Do dietary patterns determine levels of vitamin B6, folate, and vitamin B12 intake and corresponding biomarkers in European adolescents? The Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study.

OBJECTIVES: To determine dietary patterns (DPs) and explain the highest variance of vitamin B6, folate, and B12 intake and related concentrations among European adolescents. METHODS: A total of 2173 adolescents who participated in the Healthy Lifestyle in Europe by Nutrition in Adolescence study met the eligibility criteria for the vitamin B intake analysis (46% boys) and 586 adolescents for the biomarkers analysis (47% boys). Two non-consecutive, 24-h, dietary recalls were used to assess the mean intakes. Concentrations were measured by chromatography and immunoassay testing. A reduced rank regression was applied to elucidate the combined effect of food intake of vitamin B and related concentrations. RESULTS: The identified DPs (one per vitamin B intake and biomarker and by sex) explained a variability between 34.2% and 23.7% of the vitamin B intake and between 17.2% and 7% of the biomarkers. In the reduced rank regression models, fish, eggs, cheese, whole milk and buttermilk intakes were loaded positively for vitamin B intake in both sexes; however, soft drinks and chocolate were loaded negatively. For the biomarkers, a higher variability was observed in the patterns in terms of food loads such as alcoholic drinks, sugars, and soft drinks. Some food items were loaded differently between intakes and biomarkers such as fish products, which was loaded positively for intakes but negatively for plasma folate in girls. CONCLUSIONS: The identified DPs explained up to 34.2% and 17.2% of the variability of the vitamin B intake and plasma concentrations, respectively, in European adolescents. Further studies are needed to elucidate the factors that determine such patterns.

Prevalence of Metabolically Healthy but Overweight/Obese Phenotype and Its Association With Sedentary Time, Physical Activity, and Fitness.

PURPOSE: Childhood obesity is one of the major concerns in the last years due to the association with future health problems and all-cause mortality. However, there is a subset of adolescents with overweight/obesity who present a metabolic healthy profile. Therefore, the aim of this study was to examine the prevalence of metabolically healthy but overweight/obese adolescents and whether sedentary time, physical activity, and fitness differ between metabolically healthy and nonmetabolically healthy phenotypes. METHODS: A subsample of 237 European adolescents from the HEalthy Lifestyle in Europe by Nutrition in Adolescence study (n = 3,528, participation rate: 61.3%) with overweight/obesity were included. The study sample was not fully representative for the European adolescent population. Based on sex- and age-specific metabolic syndrome cutoff points for triglycerides, glucose, blood pressure, and high-density cholesterol participants were classified as metabolically healthy or nonmetabolically healthy. Sedentary time, physical activity, and fitness were assessed by accelerometry and the Alpha battery, respectively. RESULTS: The prevalence of metabolically healthy status in adolescents with overweight and obesity was higher in girls (87%) than in boys (74%, p = .019), being similar when only obesity was considered. Sedentary time was lower in metabolically healthy overweight/obese than in nonmetabolically healthy participants (mean difference = 48.0 minutes, p = .012). Moderate and moderate-to-vigorous physical activity were higher (p's < .05) in metabolically healthy than in nonmetabolically healthy adolescents with overweight/obesity (mean difference = 7.9 min/day and 10.9 min/day, respectively). No significant differences were found in fitness. Overall, these results persisted when only adolescents with obesity were included in the analyses. CONCLUSIONS: Metabolically healthy adolescents with overweight/obesity are less sedentary and more active than their nonmetabolically healthy peers with overweight/obesity, yet consistent differences in fitness were not observed.

Moderators of the effectiveness of a web-based tailored intervention promoting physical activity in adolescents: the HELENA Activ-O-Meter.

BACKGROUND: The aim of this study was to examine the moderation effects of sex, age, and psychosocial determinants (intention, social support, and modeling) of physical activity (PA) in the relationship between an Internet-based computer-tailored intervention program (Activ-O-Meter) and modes of PA and commuting. METHODS: The Activ-O-Meter with intervention and control condition was delivered to 555 adolescents (boys 50.5%, mean age: 14.4 years) in 6 European cities. Data on different modes of PA and commuting, sex, age, and psychosocial determinants were collected at baseline and at 3-months follow-up, using questionnaires. The moderation effects of psychosocial determinants, sex, and age on the association between condition and modes of PA and commuting were tested with linear regression. RESULTS: Moderation analysis showed that the following increased adolescents' responsiveness to the intervention: male sex, older age, higher baseline intention to increase PA, higher perceived social support or modeling level by siblings, and low perceived social support by friends. CONCLUSIONS: These findings should be taken into consideration when planning PA interventions in adolescents. Future intervention studies should also include moderation analysis in order to get a deeper understanding of why interventions are not effective for certain individuals and how this unresponsiveness could be overcome.

Psychosocial determinants and perceived environmental barriers as mediators of the effectiveness of a web-based tailored intervention promoting physical activity in adolescents: the HELENA Activ-O-Meter.

BACKGROUND: The aim was to examine if psychosocial determinants (attitudes, self-efficacy, social support from a sports partner) and perceived environmental barriers (PEB) of physical activity (PA) mediated the effect of a 3-month Internet-based intervention on PA in European adolescents. METHODS: A sample of 536 adolescents (51% boys) aged 12-17 years were randomly assigned to intervention or control condition. Questionnaires were used to assess different PA behaviors, psychosocial determinants and PEB at baseline and at 3-month follow-up. Mediating effects were assessed with the bootstrapping method. RESULTS: PEB regarding neighborhood safety mediated the effect of the intervention on all PA indices. PEB regarding sports facilities availability at neighborhood and PEB regarding sport-related facilities availability at school mediated the effect of the intervention on moderate to vigorous PA (MVPA) and moderate PA (in leisure time and at school, respectively). Social support from a sports partner suppressed the effect of the intervention on vigorous PA and MVPA. No other factor had a mediation effect. CONCLUSIONS: All PEB measures appear to mediate PA behaviors of different intensities and in different contexts. Interventions promoting PA in adolescents should also focus on improving the targeted PEB as mediators of engagement in PA to bring the desired effects in actual behaviors.

Dietary lipid intake only partially influences variance in serum phospholipid fatty acid composition in adolescents: impact of other dietary factors.

The present study aimed to assess the correlation between food and fatty acid (FA) intake and the serum phospholipid (PL) FA status in European adolescents and explored the percentage of variation in serum PL FA that could be attributed to dietary habits. Participants included 528 adolescents recruited in the HELENA Study. Dietary intake was assessed by two, self-administered, non-consecutive 24-h recalls. PL FA concentrations were measured in fasting venous serum samples. Reduced rank regressions were applied to examine the combined effect of food intakes. Results indicated that the variance in serum PL FA in adolescents, that could be explained by diet varied from 7.0% for MUFA to 14.2% for n-3FA. The variance in the long-chain n-3FA was mainly explained by fish intake but also by coffee and tea consumption. In conclusion this study indicated that dietary intake influences the serum PL FA status to a limited amount but that also other factors interfere. However, dietary intake is important as it is among those factors that could be modified. Furthermore, the results suggest that the overall dietary habits should be considered instead of only the consumption of single foods or nutrients, as the medium of the food or concomitant intake of foods and nutrients might interact and as such influence absorption or metabolism.

Impact of weight loss and maintenance with ad libitum diets varying in protein and glycemic index content on metabolic syndrome.

OBJECTIVES: We investigated the effects of weight loss and maintenance with diets that varied with regard to protein content and glycemic index (GI) on metabolic syndrome (MetSyn) status. METHODS: Secondary analyses were performed within the Diet, Obesity and Genes (DiOGenes) study (2006-2008), a randomized controlled dietary intervention. Nine hundred and thirty-eight overweight and obese adults from eight European countries entered an 8-wk low-calorie-diet period. Seven hundred and seventy-three adults who lost at least 8% of their body weights were randomized to one of five ad libitum diets for 6 mo: 1) low-protein (LP)/low-GI (LGI); 2) LP/high-GI (HGI); 3) high-protein (HP)/LGI; 4) HP/HGI; and 5) control diet. MetSyn prevalence and a standardized MetSyn score were assessed at baseline, after the low-calorie diet, and after the intervention. RESULTS: Weight loss among participants while on the low-calorie diet significantly reduced MetSyn prevalence (33.9% versus 15.9%; P < 0.001) and MetSyn score (-1.48 versus -4.45; P < 0.001). During weight maintenance, significant changes in MetSyn score were observed between the groups, with the highest increase detected in the LP/HGI group (P = 0.039, partial η(2) = 0.023). Protein, GI, and their interaction did not have isolated effects on study outcomes. CONCLUSIONS: Neither protein nor GI affected MetSyn status in this sample of European overweight and obese adults. However, a diet with a combination of an increased protein-to-carbohydrate ratio with low-GI foods had beneficial effects on MetSyn factors.

Reference values for leptin, cortisol, insulin and glucose, among European adolescents and their association with adiposity: the HELENA study.

BACKGROUND AND OBJECTIVE: Adequate concentrations of leptin, cortisol, and insulin are important for a suitable metabolism and development during adolescence. These hormones jointly with glucose play a major role in fat metabolism and development of childhood obesity. Our main objective was to quantify biomarkers as leptin, cortisol, insulin and glucose status in European adolescents to contribute to establish reference ranges. METHODS: A representative sample of 927 adolescents (45% males, 14.9±1.2 years for the overall population) from ten European cities of the HELENA study was used to obtain fasting blood samples for these biomarkers. The percentile distributions were computed by sex and age and percentiles were associated with BMI classification. RESULTS: Serum leptin concentration in adolescents varied significantly according to BMI, sex and age (all p < 0.001). Cortisol presented a tendency to increase with age, both for females and males, while insulin and glucose were stable with age. Leptin and insulin were highest in obese adolescents (p < 0.001), whilst cortisol and glucose did not vary with BMI. Percentiles 5, 25, 50, 75 and 95, for hormones values were, respectively: 1.27, 4.06, 11.54, 26.70 and 65.33 ng/ml for leptin; 5.00, 8.11, 11.14, 15.00 and 24.51 µg/dl for cortisol and 3.65, 6.15, 8.52, 11.90 and 20.53 µlU/ml for insulin. CONCLUSIONS: In adolescents, leptin, cortisol, insulin and glucose concentrations are differently affected by age, sex and BMI. Establishment of reference ranges (percentiles) of these biomarkers would be of great interest when pediatricians have to assess the trend of an adolescent to develop obesity years after.

Objetivo: Concentraciones adecuadas de leptina, cortisol e insulina son importantes para un metabolismo normal durante la adolescencia, puesto que valores alterados de estas hormonas, junto con la glucosa, se asocian con el desarrollo de la obesidad infantil. Nuestro principal objetivo fue cuantificar estos marcadores en adolescentes europeos con el fin de establecer rangos de referencia. Métodos: Muestras de sangre procedentes de 927 adolescentes en ayunas (14,9 ± 1,2 años, 45% varones, estudio HELENA), fueron analizadas para cuantificar la leptina, cortisol, insulina y glucosa. Las distribuciones de percentiles se determinaron teniendo en cuenta el sexo y la edad. También se estudió la asociación entre percentiles y la clasificación del IMC. Resultados: La concentración de leptina en suero variaba significativamente con el IMC, el sexo y la edad (todos p.