Nutrition in children and adolescents in Europe: what is the scientific basis? Introduction

Determining Life-Stage Groups and Extrapolating Nutrient Intake Values (NIVs)

The derivation of reference values in 11 current dietary reference standards is often based on methods of extrapolation or interpolation, but these are not consistent across reports. Such methods are frequently employed to derive nutrient intake values (NIVs) for infants and children owing to the paucity of relevant research data available. The most common method is to extrapolate values for children down from those of adults, employing a weight or metabolic factor and adjusting for growth. In some instances, values for young children are extrapolated up from infants, values for adults are extrapolated up from children, or values for older adults are extrapolated up from young adults. Extrapolation is employed to estimate not only nutrient requirement or adequate intake but also the upper tolerable levels of intake. Extrapolation methods may also form the basis of estimates of tissue deposition of nutrients during growth in children and for the maternal/fetal dyad in pregnancy with adjustments for metabolic efficiency. Likewise, recommended intakes during lactation are extrapolated from known secretion of the nutrient in milk with adjustments for bioavailability. For future dietary standards, a first priority is to obtain relevant scientific data using current methodology, such as stable isotope tracers, body composition analysis, and appropriate biomarkers, from which NIVs for each age group can be derived. Extrapolation to derive an NIV is only acceptable in the sheer absence of sound scientific data and must be modeled with a consistent approach. For the purpose of harmonization of dietary standards, we recommend the following approaches that should be clearly described in reports: standardization of age groups on a biological basis (growth and pubertal stages) with consideration of relevant developmental milestones throughout childhood; application of internationally accepted standards for growth, body size, body composition, fetal and maternal nutrient accretion in pregnancy, and milk composition; and inclusion of appropriate adjustments (metabolic efficiency, weight change, or physical activity).

Food intake in Slovenian adolescents and adherence to the Optimized Mixed Diet: a nationally representative study

Objectives

To investigate the food intake of Slovenian adolescents and to compare it with food-based dietary guidelines developed for children and adolescents, named the Optimized Mixed Diet (OMD). The OMD is a useful tool for the evaluation of food intake of adolescents.

Design

All adolescents completed an FFQ at a regional health centre; a subgroup also completed a 3 d weighed dietary protocol at home.

Setting

This study is a part of the first national representative study on the dietary habits of Slovenian adolescents.

Subjects

This cross-sectional study included a representative sample of 2813 Slovenian adolescents entering high school, aged 14–17 years, from all ten geographical regions of Slovenia.

Results

The greatest deviations from the recommended intakes of the main food groups in the OMD were significantly lower intakes of (P < 0·001, mean): vegetables (179 and 163 g/d in boys and girls, respectively), bread/cereals (271 and 226 g/d), potatoes/rice/pasta (212 and 163 g/d); in boys also a significantly lower intake of fruits (mean: 321 g/d, P < 0·001) and a significantly higher intake of meat/meat products (mean: 126 g/d, P < 0·001). Additionally, the results show too high intake of sugar-sweetened beverages and too low intakes of fish and plant oils in both genders.

Conclusions

The food intake pattern of Slovenian adolescents deviates markedly from a healthy eating pattern. Nutrition education and interventions are needed for Slovenian adolescents.

The mysterious trend in American heights in the 20th century

BACKGROUND

The secular trend in the height of the US population has been almost neglected in a comparative perspective, despite its being a useful indicator of early-life biological conditions.

AIM

The study estimated the height of the US population and compared it to Western European trends after World War II.

SUBJECTS AND METHOD

The complete set of NHES and NHANES data were analyzed, collected between 1959 and 2004 by the National Center for Health Statistics, in order to construct trends of the physical stature of US-born men and women limited to non-Hispanic blacks and whites. Also analyzed was the trend in the height of US military personnel whose parents were also born in the USA. The trends and levels were compared with those of several European populations.

RESULTS

The increase in the physical stature of US adults slowed down by mid-century concurrent with a substantial acceleration in height attainment in Western and Northern Europe. Military data corroborate this finding in the main. After being the tallest population in the world ever since colonial times, Americans are now shorter than most Western and Northern Europeans and as much as 4.7-5.7 cm shorter than the Dutch, who are the tallest in world today.

CONCLUSION

Given the well-established relationship between adult stature and early-life biological welfare, it was hypothesized that either American diets are sub-optimal or that the universal health care systems and social safety net of the European welfare states are providing a more favorable early-life health environment than does the American health care system.

Can infant feeding choices modulate later obesity risk?

Since the concept of lasting programming effects on disease risk in human adults by the action of hormones, metabolites, and neurotransmitters during sensitive periods of early development was proposed >3 decades ago, ample supporting evidence has evolved from epidemiologic and experimental studies and clinical trials. For example, numerous studies have reported programming effects of infant feeding choices on later obesity. Three meta-analyses of observational studies found that obesity risk at school age was reduced by 15-25% with early breastfeeding compared with formula feeding. We proposed that breastfeeding protects against later obesity by reducing the occurrence of high weight gain in infancy and that one causative factor is the lower protein content of human milk compared with most infant formula (the early protein hypothesis). We are testing this hypothesis in the European Childhood Obesity Project, a double-blind, randomized clinical trial that includes >1000 infants in 5 countries (Belgium, Germany, Italy, Poland, and Spain). We randomly assigned healthy infants who were born at term to receive for the first year infant formula and follow-on formula with higher or lower protein contents, respectively. The follow-up data obtained at age 2 y indicate that feeding formula with reduced protein content normalizes early growth relative to a breastfed reference group and the new World Health Organization growth standard, which may furnish a significant long-term protection against later obesity. We conclude that infant feeding practice has a high potential for long-term health effects, and the results obtained should stimulate the review of recommendations and policies for infant formula composition.

Infant feeding and later obesity risk

Some 30 years ago, Günter Dörner proposed that exposure to hormones, metabolites and neurotransmitters during limited, sensitive periods of early development exert programming effects on disease risk in human adults. Early programming of long term health has since received broad scientific support and attention. For example, evidence increases for programming effects of infant feeding choices on later obesity risk. Meta-analyses of observational studies indicate that breast feeding reduces the odds ratio for obesity at school age by about 20%, relative to formula feeding, even after adjustment for biological and sociodemographic confounding variables. We hypothesized that breast feeding protects against later obesity by reducing the likelihood of high weight gain in infancy, and that this protection is caused at least partly by the lower protein supply with breast milk relative to standard infant formulae (the "Early Protein Hypothesis"). These hypotheses are tested in the European Childhood Obesity Project, a randomized double blind intervention trial in more than 1,000 infants in five European countries (Belgium, Germany, Italy, Poland, Spain). Formula fed infants were randomized to receive during the first year of life infant formulae and follow-on-formulae with higher or lower protein contents. Follow-up at 2 years of age shows that lower protein supply with formula normalizes early growth relative to a breast fed reference group and to the WHO growth reference. These results demonstrate that modification of infant feeding practice has an important potential for long-term health promotion and should prompt a review of the recommendations and policies for infant formula composition.

Taste preferences, liking and other factors related to fruit and vegetable intakes among schoolchildren: results from observational studies

The present paper explores the relative importance of liking and taste preferences as correlates of fruit and vegetable (FV) intakes among schoolchildren in Europe. The paper first provides an overview of potential determinants of food choice among children and subsequently summarizes the results of two recent observational studies on determinants of FV intakes among school-aged children. It is proposed that taste preferences and liking are important for children's food choices as part of a broader spectrum of nutrition behaviour determinants. Taste preferences and liking are important for motivation to eat certain foods, but social-cultural and physical environmental factors that determine availability and accessibility of foods, as well as nutrition knowledge and abilities should also be considered.

Study 1 shows that children with a positive liking for FV have a greater likelihood to eat fruits (odds ratio (OR) = 1·97) or vegetables (OR = 1·60) every day, while ability and opportunity related factors such as knowledge, self-efficacy, parental influences and accessibility of FV were also associated with likelihood of daily intakes (ORs between 1·16 and 2·75). These results were consistent across different countries in Europe. Study 2 shows that taste prerences were the stongest mediator of gender differences in FV intakes among children; the fact that girls eat more could for a large extend be explained by there stronger taste preferences.

The epidemic of obesity in children and adolescents in the world

The prevalence of obesity has reached alarming levels, affecting virtually both developed and developing countries of all socio-economic groups, irrespective of age, sex or ethnicity. Concerning childhood obesity, it has been estimated that worldwide over 22 million children under the age of 5 are severely overweight, and one in 10 children are overweight. This global average reflects a wide range of prevalence levels, with the prevalence of overweight in Africa and Asia averaging well below 10% and in the Americas and Europe above 20%. The proportion of school-age children affected will almost double by 2010 compared with the most recently available surveys from the late 1990s up to 2003. In the European Union, the number of children who are overweight is expected to rise by 1.3 million children per year, with more than 300,000 of them becoming obese each year without urgent action to counteract the trend. By 2010 it is estimated that 26 million children in E.U. countries will be overweight, including 6.4 million who will be obese. Moreover, in the U.S.A. the prevalence of obesity in adolescents has increased dramatically from 5% to 13% in boys and from 5% to 9% in girls between 1966-70 and 1988-91. In this review paper we present the epidemiology of obesity in children and adolescents, including prevalence rates, trends, and risk factors associated with this phenomenon.

Traditional v. modified dietary patterns and their influence on adolescents' nutritional profile

Korea has experienced exceptionally rapid economic developments. Even though the country has managed to maintain aspects of its traditional diet, dietary habits are changing, especially among adolescents. This study was carried out to identify prevailing dietary patterns among Korean adolescents and to compare the nutrient intakes and dietary behaviours between the patterns. A 3 d diet record, collected from 671 Korean adolescents aged 12–14 years in Seoul, Korea, was assessed. By cluster analysis, subjects were classified into a modified (69·9 %) and a traditional (30·1 %) dietary pattern group. The modified group consumed more bread, noodles, cookies and pizza/hamburgers compared with the traditional group, which consumed mainly rice and kimchi (fermented cabbage). The modified group had significantly higher intakes of all nutrients. It had a higher total daily energy intake (7719 kJ), a higher daily energy intake from fat (29·8 %) and a higher cholesterol intake (326 mg/d), compared with the traditional group (6686 kJ, 24·8 % and 244 mg/d, respectively). The modified group was more likely to consume fast foods, fried foods and carbonated beverages even though they consumed more fresh fruits and milk, while the traditional group was more likely to have a rice-based diet and not to skip breakfast. These results suggest that monitoring dietary behaviours of adolescents, especially in a society experiencing a nutrition transition, is necessary in order to identify both negative and positive changes in respect of risk factors for nutrition-related chronic diseases as well as for undernutrition.

Protein intake in the first year of life: a risk factor for later obesity? The E.U. childhood obesity project

Effective strategies for primary prevention are urgently needed to combat the rapidly increasing prevalence of childhood obesity. Evidence accumulates that early nutrition programmes later obesity risk. Breast feeding reduces the odds ratio for obesity at school age, adjusted for biological and sociodemographic confounding variables, by some 20-25%. We propose that the protective effect of breast feeding is related in part by the induction of a lower weight gain in infancy, which is related to differences in substrate intake. Protein intake per kg bodyweight is some 55-80% higher in formula fed than in breast fed infants. We hypothesize that high early protein intakes in excess of metabolic requirements enhance weight gain in infancy and increase later obesity risk (the "early protein hypothesis"). The European Childhood Obesity Programme tests this hypothesis in a randomized double blind intervention trial in 1150 infants in five European centres. Infants that are not breast fed are randomized to formulae with higher or lower protein content and followed up to school age. If an effect of infant feeding habits on later obesity risk should be established, there is great potential for effective preventive intervention with a significant potential health benefit for the child and adult population.