Clinical and physical characteristics of thinness in adolescents: the HELENA study.

PURPOSE: Thinness in adolescence has not been studied as extensively as overweight or obesity. The aim of this study was to assess the prevalence, characteristics, and health impacts of thinness in a European adolescent population. METHODS: This study included 2711 adolescents (1479 girls, 1232 boys). Blood pressure, physical fitness, sedentary behaviors, physical activity (PA), and dietary intake were assessed. A medical questionnaire was used to report any associated diseases. A blood sample was collected in a subgroup of the population. Thinness and normal weight were identified using the IOTF scale. Thin adolescents were compared with adolescents of normal weight. RESULTS: Two hundred and fourteen adolescents (7.9%) were classified as being thin; the prevalence rates were 8.6% in girls and 7.1% in boys. Systolic blood pressure was significantly lower in adolescents with thinness. The age at the first menstrual cycle was significantly later in thin female adolescents than in those with normal weight. Upper-body muscular strength measured in performance tests and time spent in light PA were significantly lower in thin adolescents. The Diet Quality Index was not significantly lower in thin adolescents, but the percentage of adolescents who skipped breakfast was higher in adolescents with a normal weight (27.7% vs 17.1%). Serum creatinine level and HOMA-insulin resistance were lower and vitamin B12 level was higher in thin adolescents. CONCLUSIONS: Thinness affects a notable proportion of European adolescents with no physical adverse health consequences.

Relative validity of the Planetary Health Diet Index by comparison with usual nutrient intakes, plasma food consumption biomarkers, and adherence to the Mediterranean diet among European adolescents: the HELENA study.

PURPOSE: The EAT-Lancet Commission proposed an evidence-based global reference diet to improve human health within planetary boundaries. Recently, the Planetary Health Diet Index (PHDI) was developed based on the EAT-Lancet recommendations and validated among Brazilian adults. However, the relative validity of the PHDI in adolescents has yet to be assessed. Thus, we aimed to evaluate the relative validity of the PHDI in European adolescents. METHODS: We used cross-sectional data from 1804 adolescents (12.5-17.5 years) enrolled in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study. The PHDI (0-150 points) was calculated based on dietary intake data from two non-consecutive 24-h dietary recalls. Associations between the PHDI and usual nutrient intakes, plasma food consumption biomarkers, and adherence to the Mediterranean diet were evaluated using multivariable-adjusted mixed-effects linear regression models. RESULTS: Higher PHDI score was associated with greater intakes of nutrients predominantly from plant-source foods, such as vegetable protein, vitamin E, and folate and with lower intake of nutrients predominately from animal-source foods, such as total and saturated fat, cholesterol, and animal protein. Furthermore, a higher PHDI score was also positively associated with plasma ß-carotene, vitamin C, vitamin D, folate, and ferritin concentrations, while negatively associated with trans-fatty acids concentration. Moreover, higher PHDI was related to a greater adherence to the Mediterranean dietary pattern. CONCLUSIONS: The PHDI showed good relative validity among adolescents in the HELENA study. Hence, future research should assess adherence to the PHDI and long-term health outcomes.

Climate change and fluid status in children: early education as one response to an emerging public health problem.

OBJECTIVE: As global warming intensifies, residents of temperate regions will also face heat waves in the near future. Food habits are one component in addressing the global challenge of climate change. However, water, the most important food for humans, has not been adequately addressed. DESIGN: For this commentary, on the one hand, publications on the increasing heat stress of children were consulted. On the other hand, publications on the special demands of children's temperature regulation in hot environments on fluid balance were analysed. SETTING: The situation of young children in care facilities on days with heat stress is presented as a scenario. In this way, the effects of climatic changes on fluid balance can be estimated and measures to reduce heat stress and stabilise the fluid balance of children can be developed. PARTICIPANTS: For this analysis, first, infants will be considered in order to identify their specific fluid needs. Second, the possibilities for caregivers to improve fluid intake and train appropriate drinking habits already in infancy will be highlighted. RESULTS: Climate change should be included in recommendations on hydration for children. The need to adapt drinking habits requires educational approaches to weather and water - starting in early childhood care. CONCLUSIONS: In the face of rapid climate change, countries must act now by protecting, preparing and prioritising the high-risk group of children. Particular focus should be placed on supporting adequate hydration.

Impact of lunch with carbohydrates differing in glycemic index on children's cognitive functioning in the late postprandial phase: a randomized crossover study.

PURPOSE: Studies about effects of lunch dietary Glycemic Index (GI) on cognition of schoolchildren are scarce. Our previous CogniDo GI study found no changes of cognition in the early postprandial phase after consumption of two rice types with medium vs. high dietary GI for lunch (i.e., 45 min after starting lunch). This study investigated whether the dietary GI of lunch has an impact on cognition of schoolchildren in the late postprandial phase, 90 min after lunch. METHODS: A randomized, 2 × 2 crossover intervention study was conducted at a comprehensive school with 5th and 6th grade students. Participants (n = 212) were randomly assigned to either sequence 1 or 2. In the first period, participants of sequence 1 received a dish with high GI rice (GI: 79), those of sequence 2 with medium GI rice (GI: 64)-in the second period, 1 week later, vice versa. Computer-based cognitive testing was performed 90 min after lunch examining tonic alertness, visual search and task switching, and working memory. Treatment effects and treatment effects adjusted for estimated lunch glycemic load (GL) were analyzed using a linear mixed model. RESULTS: The selected cognitive parameters were not affected by the GI of lunch 90 min after lunch, neither after intention-to-treat nor in the per-protocol analysis. Adjustment for GL also did not change results. CONCLUSION: The present study revealed no notable differences after the consumption of two rice types with medium vs. high dietary GI for lunch in children's cognitive function in the late postprandial phase, 90 min after lunch. CLINICAL TRIAL REGISTRATION: German Clinical Trials Register (DRKS00013597); date of registration: 16/04/2018, retrospectively registered.

Adolescents' dietary polyphenol intake in relation to serum total antioxidant capacity: the HELENA study.

We evaluated the association between intake of total polyphenols, polyphenol classes and the 10 most consumed individual polyphenols with serum total antioxidant capacity (TAC) in 749 European adolescents (53% girls; 15% overweight; 12.5-17.5 years-old) from the cross-sectional HELENA study of 2006-2007. Dietary polyphenol intake was calculated from two non-consecutive 24-h recalls matched with the Phenol-Explorer database. Multilevel linear models examined the associations between dietary polyphenols and TAC. Polyphenol intake was rather low (median = 321mg/day; p25 = 158; p75 = 536) and TAC was comparable to other literature findings (median = 1.57 mmol/L; p25 = 1.45; p75 = 1.74). Total polyphenol intake, polyphenol classes and the top 10 compounds were not associated with TAC in a linear, quadratic or cubic way in partially or fully confounder-adjusted models. A direct anti-oxidative effect of dietary polyphenol intake was not observed in European adolescents. Polyphenol biomarkers and additional antioxidant measures are needed in future prospective studies to confirm these results.

The role of breastfeeding promotion in German hospitals for exclusive breastfeeding duration.

Breastfeeding promotion and support in hospitals is expected to have a positive impact on maternal breastfeeding outcomes. The objective of this study is to examine the association between breastfeeding promotion in maternity hospitals in Germany and exclusive breastfeeding (EBF) rates during the first 4 months. Thus, a nationwide cross-sectional web-based survey of breastfeeding promotion was conducted in 103 hospitals. Mother-infant pairs (n = 962) were recruited at these hospitals for a prospective web-based survey of breastfeeding status at five-time points, that is, during a hospital stay, at discharge as well as after 0.5, 2, and 4 months. The hospital analysis was based on the "10 Steps to Successful Breastfeeding" of the World Health Organization and the United Nations Children's Fund, adapted for Germany. Their degree of implementation was stratified by a breastfeeding promotion index (BPI) as low (≤5 steps), medium (6-8 steps), and high (≥9 steps). The association between the BPI and the odds of EBF at each of the five-time points was estimated by multivariable regression models, adjusting for various maternal factors. At all time points, the proportion of EBF among mothers from high BPI hospitals exceeded the proportion of those from medium or low BPI hospitals. A high BPI was associated with higher odds of EBF during the hospital stay and at discharge, while maternal factors for EBF such as breastfeeding experience and no early use of a pacifier persisted beyond. The high commitment of hospitals and tailored support of mothers is essential for EBF.

Cardiometabolic Risk is Positively Associated with Underreporting and Inversely Associated with Overreporting of Energy Intake Among European Adolescents: The Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) Study.

BACKGROUND: Dietary misreporting is the main limitation of dietary assessments and has been associated with BMI during youth. However there are no prior studies assessing misreporting and cardiometabolic risks (CMRs) in adolescence. OBJECTIVES: To examine the associations between dietary misreporting and CMR factors in adolescents and to assess the potential bias in the association between CMR and energy intake (EI) driven by dietary misreporting. METHODS: Two 24-hour dietary recalls were obtained from 1512 European adolescents (54.8% girls) aged 12.5-17.5 years. Physical activity was measured by accelerometry. Cut-offs suggested by Huang were applied to identify misreporters. Height, waist circumference (WC), the sum of 4 skinfold thicknesses, diastolic blood pressure (DBP), systolic blood pressure (SBP), and cardiorespiratory fitness (CRF) measurements were taken and serum triglycerides and total-/high-density lipoprotein cholesterol ratio were analyzed. A sex- and age-specific clustered CMR score (n = 364) was computed. Associations were investigated by multilevel regression analyses adjusting for age, sex, center, socioeconomic status, and physical activity. RESULTS: Underreporting (24.8% adolescents) was significantly (P < 0.05) associated with a higher WC, waist-to-height ratio (WHeR), and sum of skinfold thickness, whereas overreporting (23.4% adolescents) was significantly associated with a lower WC, WHeR, sum of skinfold thickness, and SBP. Associations between CMR factors and EI were significantly affected by misreporting, considering various approaches. Significant, positive associations became inverse after adjusting for misreporting for WC and WHeR. The opposite was true for the sum of skinfold thickness, SBP, and CMR score. The associations between EI and DBP and CRF did not remain significant after adjusting for misreporting. CONCLUSIONS: CMR factors differed among misreporting groups, and both abdominal and total fat mass indicators were more strongly associated with all forms of misreporting than was BMI. Moreover, misreporting seems to bias EI and CMR associations in adolescents. Therefore, energy misreporting should be taken into account when examining diet-CMR associations.

Breast-feeding promotion in hospitals and prospective breast-feeding rates during the first year of life in two national surveys 1997-1998 and 2017-2019 in Germany.

OBJECTIVES: The present study aimed to assess the current state of breast-feeding promotion in hospitals and the prevalence of breast-feeding during the first year of life in Germany and to compare the results with a study 20 years earlier. DESIGN: In the studies on 'breast-feeding and infant nutrition in Germany' named 'SuSe', a cross-sectional survey in hospitals was combined with a subsequent prospective survey of breast-feeding and infant nutrition during the first year of life (0·5, 2, 4, 6 and 12 months after birth) in mother-infant pairs who were recruited in the hospitals. Written questionnaires and phone calls were used in SuSe I and web-based questionnaires in SuSe II. Breast-feeding promotion and prevalence were evaluated using recommendations from the WHO and the UNICEF. SETTING: Two nationwide surveys SuSe I (1997-1998) and SuSe II (2017-2019). PARTICIPANTS: In SuSe I, 177 hospitals and 1717 mother-infant pairs and in SuSe II 109 hospitals and 962 mother-infant pairs were included. RESULTS: In SuSe II, hospitals implemented seven of the WHO 'Ten Steps to Successful Breastfeeding' to a greater extent than the hospitals in SuSe I. More mothers exclusively breastfed for 4 months (57 % v. 33 %) and continued breast-feeding until 6 (78 % v. 48 %) and 12 months (41 % v. 13 %). In both studies, exclusive breast-feeding decreased between 4 and 6 months of age due to the introduction of complementary feeding. CONCLUSIONS: In Germany, breast-feeding habits have come closer to the recommendations over the last 20 years.

Total Polyphenol Intake Is Inversely Associated with a Pro/Anti-Inflammatory Biomarker Ratio in European Adolescents of the HELENA Study.

BACKGROUND: Although high dietary polyphenol intake is negatively associated with risk of certain inflammation-associated chronic diseases, the underlying mechanisms are not fully understood and few studies have explored this in adolescents. OBJECTIVE: This study aimed to evaluate the association between intakes of total polyphenols, polyphenol classes, and the 10 most commonly consumed individual polyphenols with inflammatory biomarkers in the blood of European adolescents. METHODS: In the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) Study, 526 adolescents (54% girls; 12.5-17.5 y) had data on inflammatory biomarkers and polyphenol intake from 2 nonconsecutive 24-h recalls via matching with the Phenol-Explorer database. Inflammatory biomarkers in serum were IL-1, IL-2, IL-4, IL-5, IL-6, IL-10, transforming growth factor ß1 (TGF-ß1), TNF-α, IFN-γ, soluble vascular adhesion molecule 1 (sVCAM-1), soluble intercellular adhesion molecule 1 (sICAM-1), soluble E-selectin (sE-selectin), white blood cells, lymphocytes, T cells, and C-reactive protein. Multilevel linear models were used to test associations of polyphenol intake with a pro/anti-inflammatory biomarker ratio [(zTNF-α + zIL-6 + zIL-1)/3/zIL-10] as well as with separate inflammatory biomarkers, adjusted for sociodemographic variables, diet inflammation index, BMI z score, and serum triglycerides. RESULTS: The pro/anti-inflammatory biomarker ratio was linearly inversely associated with the intake of total polyphenols (ß = -0.11, P = 0.040). When other inflammation biomarkers were considered, the serum IL-10 concentration was inversely associated with total polyphenol (ß = -0.12, P = 0.017) and flavonoid (ß = -0.12, P = 0.013) intakes, findings that were inconsistent with the biomarker ratio results. However, the anti-inflammatory capacity of polyphenols was confirmed by positive associations of IL-4 with phenolic acid (ß = 0.09 P = 0.049) and stilbene (ß = 0.13, P = 0.019) intakes and the negative association of IL-1, IL-2, and IFN-γ with lignan intake (ß = -0.10, P = 0.034; ß = -0.09, P = 0.049; ß = -0.11, P = 0.023). CONCLUSIONS: The negative relation with the overall pro/anti-inflammatory biomarker ratio suggests a potential anti-inflammatory role of high polyphenol intakes among European adolescents. Nevertheless, associations are dependent on polyphenol type and the inflammatory biomarker measured.

Polyphenol intake and metabolic syndrome risk in European adolescents: the HELENA study.

PURPOSE: The role of polyphenol intake during adolescence to prevent metabolic syndrome (MetS) is little explored. This study aimed to evaluate the association between intake of total polyphenols, polyphenol classes and the 10 most consumed individual polyphenols with MetS risk in European adolescents. METHODS: Of the cross-sectional HELENA study, 657 adolescents (54% girls; 14.8% overweight; 12.5-17.5 year) had a fasting blood sample and polyphenol intake data from two non-consecutive 24-h recalls matched with the Phenol-Explorer database. MetS was defined via the pediatric American Heart Association definition. Multilevel linear regressions examined the associations of polyphenol quartiles with MetS components, while logistic regression examined the associations with MetS risk. RESULTS: After adjusting for all potential confounders (socio-demographics and nine nutrients), total polyphenol intake, polyphenol classes and individual polyphenols were not associated with MetS risk. From all MetS components, only BMI z-score was modestly inversely associated with total polyphenol intake. Further sub analyses on polyphenol classes revealed that flavonoid intake was significantly associated with higher diastolic blood pressure and lower BMI, and phenolic acid intake was associated with higher low-density cholesterol. For individual polyphenols, the above BMI findings were often confirmed (not independent from dietary intake) and a few associations were found with insulin resistance. CONCLUSION: Higher intakes of total polyphenols and flavonoids were inversely associated with BMI. No consistent associations were found for other MetS components.

Translation of EU Food Law and Nutrient Reference Values Into Practice: the German Dietary Scheme for the First Year of Life.

OBJECTIVES: European dietary regulations affect national dietary guidelines for child nutrition. The update of the German Dietary Scheme for the first year of life is used to examine the translation of European nutrient references into food-based guidelines while maintaining traditional habits. METHODS: Within the Dietary Scheme, intake of energy and nutrients was calculated in the complementary feeding period for each of the 3 daily recommended complementary meals (a vegetable-potato-meat meal, a milk-cereal meal, a cereal-fruit meal) in addition to the daily liquid-milk servings (breast milk or follow-on formula). Pureed-home-made complementary meals were assumed. The adequacy of nutrient intake was evaluated by comparison with the European Food Safety Authority (EFSA) Dietary Reference Values. Macronutrient content of meals was compared to the European complementary food directive. RESULTS: Daily intake of most nutrients following the scheme was well in line with EFSA values, whereas the commonly 'critical' nutrients iron and iodine remained far below EFSA values. Substituting breast milk or whole cow's milk with follow-on formula had only a small impact on nutrient supply. Although the different nutrient profiles of meals were not fully in line with European regulations, they add up to an overall balanced daily diet. CONCLUSIONS: Taken together, European dietary reference values for energy and nutrients can mostly be met by the modular system of the Dietary Scheme as a total diet concept for infant nutrition in Germany. The different proposed meals generally agree with EU regulations for complementary food.

A new measure of health motivation influencing food choices and its association with food intakes and nutritional biomarkers in European adolescents.

OBJECTIVE: To develop a scale to assess health motivation influencing food choices and to explore its performance in the associations with food intakes and nutritional biomarkers. DESIGN: Psychometric study using cross-sectional self-report questionnaires and nutritional biomarkers. SETTING: Multi-centre investigation conducted in ten European cities. PARTICIPANTS: 2954 adolescents who were included in the HELENA study and completed the Food Choices and Preferences (FCP) questionnaire. RESULTS: Nineteen out of 124 items of the FCP questionnaire were in the same dimension. Sixteen presented adequate parameters for the Scale of evaluatiOn of Food choIcEs (SOFIE). The scores were positively associated with the intakes of cereals, dairy products, meats and eggs, and fish, as well as with blood concentrations of vitamin C, ß-carotene, n-3 fatty acids, cobalamin, holo-transcobalamin and folate; scores were negatively associated with the intake of alcohol. CONCLUSIONS: SOFIE can improve the assessment of motivation influencing food choices based on items with the best performance and is proposed as a new measure to health-related studies.

Dietary Patterns and Their Relationship With the Perceptions of Healthy Eating in European Adolescents: The HELENA Study.

Objective: The aim of this study was to identify dietary patterns (DPs) in European adolescents and to examine the association between perceptions of healthy eating and the obtained DPs.Method: A multinational cross-sectional study was carried out in adolescents aged 12.5 to 17.5 years and 2,027 (44.9% males) were considered for analysis. A self-reported questionnaire with information on food choices and preferences, including perceptions of healthy eating, and two 24-hour dietary recalls were used. Principal component analysis was used to obtain sex-specific DPs, and linear analyses of covariance were used to compare DPs according to perceptions of healthy eating.Results: Three and four DPs for boys and girls were obtained. In boys and girls, there were significant associations between some perceptions about healthy food and the Breakfast-DP (p < 0.05). In boys, Breakfast-DP and Healthy Beverage-DP were associated with the perception of the own diet as healthy (p < 0.05). Healthy Beverage-DP was associated with those disliking fruits and vegetables (p < 0.05). Girls considering the own diet as healthy were associated with Mediterranean-DP, Breakfast-DP, and Unhealthy Beverage and Meat-DP (p < 0.05). The perception of snacking as a necessary part of a healthy diet was associated with Breakfast-DP in both genders (p < 0.05).Conclusions: In European adolescents, perceptions of healthy eating were mainly associated with a DP characterized by foods consumed at breakfast. Future studies should further explore these findings in order to implement health promotion programs to improve healthy eating habits in adolescents.

Adherence to the Mediterranean diet in metabolically healthy and unhealthy overweight and obese European adolescents: the HELENA study.

PURPOSE: To examine the adherence to the Mediterranean dietary pattern (MDP) in metabolically healthy overweight or obese (MHO) and metabolically unhealthy obese (MUO) European adolescents. METHODS: In this cross-sectional study, 137 overweight/obese adolescents aged 12-17 years old from the HELENA study were included. Height, weight, waist circumference and skinfold thickness were measured and body mass index and body fat percent were calculated. Systolic and diastolic blood pressure, glucose, HDL cholesterol, triglycerides and cardiorespiratory fitness (20 m shuttle run test) were measured. MHO and MUO phenotypes were categorized following the Jolliffe and Janssen criteria. Two non-consecutive 24 h recalls were used for dietary intake assessment and the adherence to the MDP was calculated using the Mediterranean dietary pattern score (MDP score) (range 0-9). RESULTS: A total of 45 (22 girls) adolescents (32.8%) were categorized as MHO. The adherence to the MDP was significantly higher in MHO than in MUO adolescents regardless of age, sex, body fat percentage, energy intake and center (MDP score: 4.6 ± 1.6 vs. 3.9 ± 1.5, p = 0.036), but this difference became non-significant after further adjustment for cardiorespiratory fitness. Participants who had a low adherence to the MDP (MDP score ≤ 4) had a higher likelihood of having MUO phenotype regardless of sex, age, energy intake, center and body fat percentage (OR 2.2; 95% CI 1.01-4.81, p = 0.048). CONCLUSIONS: Adherence to the MDP might be beneficial to maintain metabolic health in overweight/obese adolescents, yet cardiorespiratory fitness seems to play a key role on the metabolic phenotype.

Diet as moderator in the association of adiposity with inflammatory biomarkers among adolescents in the HELENA study.

AIM: Our aim is to demonstrate that a healthy diet might reduce the relation between adiposity and inflammation, whereas an unhealthy diet may increase the effect of adiposity on inflammatory biomarkers. METHODS: In 618 adolescents (13-17 years) of the European HELENA study, data were available on body composition, a set of inflammation markers, and food intake determined by a self-administered computerized 24-h recall. A 9-point Mediterranean diet score and an antioxidant-rich diet score were used as dietary parameters and tested as moderator. Total body fat was represented by the sum of six skinfold thicknesses and central adiposity by waist circumference. A set of inflammation-related biomarkers was used as outcome: a pro/anti-inflammatory interleukins ratio, TGFß-1, C-reactive protein, TNF-α, 3 cell adhesion molecules, and 3 types of immune cells; gamma-glutamyltransferase (GGT) and homocysteine were used as cardiovascular disease risk biomarkers, and alanine transaminase (ALT) as liver dysfunction biomarker. Multiple linear regression analyses tested moderation by diet in the adiposity-inflammation association and were adjusted for age, sex, country, puberty, socioeconomic status. RESULTS: Both the Mediterranean and antioxidant-rich diet, and overall and central adiposity, were important in the moderation. Diet was a significant protective moderator in the effect of adiposity on the pro/anti-inflammatory interleukins ratio, TGFß-1, GGT, and ALT. CONCLUSION: In conclusion, in some cases, a diet rich in antioxidants and essential nutrients may attenuate the concentration of inflammatory biomarkers caused by adiposity, whereas a poor diet appears to contribute to the onset of early oxidative stress signs.

Diet as a moderator in the association of sedentary behaviors with inflammatory biomarkers among adolescents in the HELENA study.

AIM: To assess if a healthy diet might attenuate the positive sedentary-inflammation relation, whereas an unhealthy diet may increase the effect of sedentary behaviors on inflammatory biomarkers. METHODS: In 618 adolescents (13-17 years) of the European HELENA study, data were available on body composition, a set of inflammation markers, and food intake assessed by a self-administered computerized 24 h dietary recall for 2 days. A 9-point Mediterranean diet score and an antioxidant-rich diet z-score were used as dietary indices and tested as moderators. A set of low-grade inflammatory characteristics was used as outcome: several cytokines in an inflammatory ratio (IL-6, IL-10, TNF-α, TGFß-1), C-reactive protein, three cell-adhesion molecules (sVCAM-1, sICAM-1, sE-selectin), three cardiovascular risk markers (GGT, ALT, homocysteine) and three immune cell types (white blood cells, lymphocytes, CD3). Sedentary behaviors were self-reported and analyzed as total screen time. Multiple linear regression analyses tested moderation by diet in the sedentary behaviors-inflammation association adjusted for age, sex, country, adiposity (sum of six skinfolds), parental education, and socio-economic status. RESULTS: Both diet scores, Mediterranean and antioxidant-rich diet, were significant protective moderators in the effect of sedentary behaviors on alanine-transaminase enzyme (P = 0.014; P = 0.027), and on the pro/anti-inflammatory cytokine ratio (P = 0.001; P = 0.004), but not on other inflammatory parameters. CONCLUSION: A higher adherence to the Mediterranean diet or an antioxidant-rich diet may attenuate the onset of oxidative stress signs associated by sedentary behaviors, whereas a poor diet seems to increase inflammation.

Estimated dietary intake of polyphenols in European adolescents: the HELENA study.

PURPOSE: Knowledge about polyphenols intakes and their determinants among adolescents might be helpful for planning targeted prevention strategies at an early age. METHODS: In the European multicenter cross-sectional HELENA study of 2006-2007, 2428 subjects (47% boys) had data on dietary intake of polyphenols from 2 non-consecutive 24 h recalls via linking with the Phenol-Explorer database. Differences by sex, age, country, BMI, maternal education, paternal education, family affluence, smoking status, alcohol use, and physical activity were explored by linear regression. RESULTS: Median, lower and upper quartiles of polyphenol intakes were 326, 167 and 564 mg/day, respectively. Polyphenol intake was significantly higher in the oldest (16-17.49 years), girls, non-Mediterranean countries, lowest BMI, highest paternal education, and alcohol consumers. Main food contributors were fruit (23%, mainly apple and pear, i.e., 16.3%); chocolate products (19.2%); and fruit and vegetable juices (15.6%). Main polyphenol classes were flavonoids (75-76% of total) and phenolic acids (17-19% of total). The three most consumed polyphenols were proanthocyanidin polymers (> 10 mers), hesperidin, and proanthocyanidin 4-6 oligomers. CONCLUSION: The current study provided for the first time numbers on the total polyphenol intake and their main food sources in a heterogeneous group of European adolescents. Major differences with adult populations are the lower polyphenol consumption and the major food sources, such as chocolate and biscuits. The discussed determinants and polyphenol types already point to some important population groups that need to be targeted in future public health initiatives.

Measuring nutritional knowledge using Item Response Theory and its validity in European adolescents.

OBJECTIVE: To analyse the Nutritional Knowledge Test (NKT) using Item Response Theory (ITR) analysis and to assess the construct validity of the Nutritional Knowledge Scale (NKTS) and its associations with adolescent food group consumption and nutritional biomarkers. DESIGN: Cross-sectional study. SETTING: Multicentre investigation conducted in ten European cities.ParticipantsAdolescents aged 12·5-17·5 years (n 3215) who completed over 75 % of the NKT. RESULTS: Factor analysis indicated that the NKT can be analysed with a one-dimensional model. Eleven out of twenty-three items from the NKT presented adequate parameters and were selected to be included in the NKTS. Nutrition knowledge was positively associated with consumption of fruits, cereals, dairy products, pulses, meat and eggs, and fish, as well as with blood concentrations of vitamin C, ß-carotene, n-3 fatty acids, holo-transcobalamin, cobalamin and folate; nutrition knowledge was negatively associated with intake of olives and avocado, alcohol and savoury snacks. CONCLUSIONS: The NKTS assessed nutritional knowledge adequately and it is proposed as a new tool to investigate this subject in future studies.

Relative validation of the adapted Mediterranean Diet Score for Adolescents by comparison with nutritional biomarkers and nutrient and food intakes: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study.

OBJECTIVE: To investigate whether adherence to the adapted Mediterranean Diet Score for Adolescents (MDS_A) and the adapted Mediterranean Diet Quality Index for Adolescents (KIDMED_A) is associated with better food/nutrient intakes and nutritional biomarkers. DESIGN: The Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study is a cross-sectional study aiming to obtain comparable data on a variety of nutritional and health-related parameters in European adolescents aged 12·5-17·5 years. SETTING: Nine European countries. PARTICIPANTS: European adolescents (n 2330) recruited to the HELENA study. Dietary intake was obtained with 24 h dietary recalls, an FFQ and a Food Choices and Preferences questionnaire. MDS_A was calculated as a categorical variable using cut-offs (MDS_A), as a continuous variable (zMDS_A) and with energy adjustments (zEnMDS_A). The KIDMED_A score was also calculated. RESULTS: Multilevel linear regression analysis showed positive associations for zMDS_A and KIDMED_A with serum levels of vitamin D, vitamin C, plasma folate, holo-transcobalamin, ß-carotene and n-3 fatty acids, while negative associations were observed with trans-fatty acid serum levels. For categorical indices, blood biomarkers showed few significant results. zMDS_A and KIDMED_A showed positive associations with vegetables and fruits intake, and negative associations with energy-dense and low-nutritious foods. zMDS_A and KIDMED_A were positively associated with all macronutrients, vitamins and minerals (all P < 0·0001), except with monosaccharides and PUFA for KIDMED_A and cholesterol for both indices (P < 0·05). CONCLUSIONS: zMDS_A and KIDMED_A have shown the strongest associations with the dietary indicators and biomarkers that have been associated with the Mediterranean diet before, and are therefore considered the most appropriate and valid Mediterranean diet scores for European adolescents.

Association between full breastfeeding, timing of complementary food introduction, and iron status in infancy in Germany: results of a secondary analysis of a randomized trial.

PURPOSE: Considering the low content in breast milk breastfed infants might be at particular risk for depleted iron stores after the first months of life. This study evaluates the association of the mode of milk feeding and the timing of complementary food (CF) introduction with parameters of iron status in term healthy infants in Germany. METHODS: In this secondary analysis of a randomized controlled trial, parents recorded all foods consumed by their infants from the age of 8 weeks onwards. Mothers were advised on the German food-based dietary guidelines for infants. Accordingly, CF was introduced between the fifth and seventh month of age. Blood samples were taken at 4 and at 10 months of age for analyses of iron status parameters. Iron depletion was defined as serum ferritin <12 ng/mL. RESULTS: The iron intake was lower in breastfed infants (n = 50) than in formula fed (n = 23) with decreasing differences during the course of infancy. At 10 months of age, most iron parameters were not associated with the mode of milk feeding or the timing of CF introduction. At this age, the iron depletion prevalence was >34% without general differences according to the mode of milk feeding or the timing of CF introduction. CONCLUSION: The high prevalence of depleted iron stores observed in both breastfed and formula-fed infants illustrates the need for further studies to improve our understanding of the optimal iron intake and sensitive parameters of iron status in infancy.