Dietary Behavior and Physical Activity in Children and Adolescents

In recent years, diet- and lifestyle-related disorders have become a major health threat in Europe and worldwide [...].

evaluated all four validity measures. Face validity was evaluated by expert reviews of representative foods and food amounts, considering whether representative foods can be realistically found in the target population's home. Content validity was assessed by iterative runs and via the removal of each food individually from the score database to determine whether the representative food was loading into the component scores as theorized Criterion validity was assessed by testing the contributions of each food to component and total scores. Finally, construct validity was evaluated by testing five hypothetical home food environments that resulted in a range of scores in the expected directions. Using a validated FFQ, Wolters M. et al. confirmed a positive association between frequent fast food consumption and adverse changes in body composition indicators in two German pediatric cohorts [20].
Two European studies evaluated the prevalence and determinants of dietary supplement use in children and adolescents, an important research question given that dietary supplement use has been implicated in preventable adverse drug events and emergency department visits in children and adolescents [21,22]. Data from the KiGGS Module EsKiMo II study showed that around 16% of adolescents in Germany use dietary supplements [9], and data from Eastern Poland reported that around 30% of children and adolescents use vitamin or mineral supplements [23]. Notably, the time frame for which supplement intake was queried was different in these two studies; in Germany the time frame was the previous four weeks and in Poland the past 12 months. In comparison, 33% of children and adolescents in the United States use dietary supplements [21]. In the two European studies, supplement users were more often female, living in urban areas, from more highly educated families, more likely to be physically active, and less likely to be overweight or obese [9,23].
Growing up in lower socio-economic environments or vulnerable groups such as ethnic minorities may increase susceptibility to unhealthy dietary patterns [24]. The study in this Special Issue from New Caledonia reported that the proportion of adolescents regularly consuming sugar-sweetened beverages was high (90%) and was related to living in rural areas and belonging to a particular ethnic community [25]. Results from the WHO Health Behavior in School-Aged Children survey in Belgium are in line with previous findings which showed that eating culture plays a role in inequalities of eating habits among immigrants when socioeconomic conditions are considered [26]. Mustafa N. et al. [27] further highlighted that the type of foods consumed at breakfast are highly dependent on culture. Malaysian adolescents consume breakfast that is of low nutrient quality, such as cereal-based and often primarily rice dishes, chocolate and confectionary, hot and powered drinks, and noodles. The Malaysian study suggests that breakfast consumption is related to lower cardiovascular risk because of the earlier timing of food intake rather than the types of foods consumed at breakfast. This interesting hypothesis remains to be established in randomized trials.
The diverse articles in this Special Issue highlight the complexity and extent to which nutrition and physical activity behaviors may influence different health aspects of children and adolescents. Few studies in this Special Issue combined genetic data with nutritional data [28], a likely expanding research area in the coming years, with the goal to provide personalized and gene-based dietary recommendations in the future. As seen by the various findings and recommendations, not only is more work in this area required but the translation of this work to practice and policy is imperative if we are to address the challenges impacting the nutrition, physical activity, and health of young populations.

Conflicts of Interest:
The authors declare no conflict of interest.