Adolescents’ beverage choice at school and the impact on sugar intake

Background/Objectives: To examine students’ beverage choice in school, with reference to its contribution to students’ intake of non-milk extrinsic (NME) sugars. Subjects/Methods: Beverage and food selection data for students aged 11–18 years (n=2461) were collected from two large secondary schools in England, for a continuous period of 145 (school A) and 125 (school B) school days. Descriptive analysis followed by cluster analysis of the beverage data were performed separately for each school. Results: More than a third of all items selected by students were beverages, and juice-based beverages were students’ most popular choice (school A, 38.6%; school B, 35.2%). Mean NME sugars derived from beverages alone was high (school A, 16.7 g/student-day; school B, 12.9 g/student-day). Based on beverage purchases, six clusters of students were identified at each school (school A: ‘juice-based’, ‘assorted’, ‘water’, ‘cartoned flavoured milk’, ‘bottled flavoured milk’, ‘high volume juice-based’; school B: ‘assorted’, ‘water with juice-based’, ‘sparkling juice/juice-based’, ‘water’, ‘high volume water’, ‘high volume juice-based’). Both schools included ‘high volume juice-based’ clusters with the highest NME sugar means from beverages (school A, 28.6 g/student-day; school B, 24.4 g/student-day), and ‘water’ clusters with the lowest. A hierarchy in NME sugars was found according to cluster; students in the ‘high volume juice-based’ cluster returned significantly higher levels of NME sugars than students in other clusters. Conclusions: This study reveals the contribution that school beverages combined with students’ beverage choice behaviour is making to students’ NME sugar intake. These findings inform school food initiatives, and more generally public health policy around adolescents’ dietary intake

Effectiveness of school food environment policies on children's dietary behaviors: A systematic review and meta-analysis.

BACKGROUND: School food environment policies may be a critical tool to promote healthy diets in children, yet their effectiveness remains unclear. OBJECTIVE: To systematically review and quantify the impact of school food environment policies on dietary habits, adiposity, and metabolic risk in children. METHODS: We systematically searched online databases for randomized or quasi-experimental interventions assessing effects of school food environment policies on children's dietary habits, adiposity, or metabolic risk factors. Data were extracted independently and in duplicate, and pooled using inverse-variance random-effects meta-analysis. Habitual (within+outside school) dietary intakes were the primary outcome. Heterogeneity was explored using meta-regression and subgroup analysis. Funnel plots, Begg's and Egger's test evaluated potential publication bias. RESULTS: From 6,636 abstracts, 91 interventions (55 in US/Canada, 36 in Europe/New Zealand) were included, on direct provision of healthful foods/beverages (N = 39 studies), competitive food/beverage standards (N = 29), and school meal standards (N = 39) (some interventions assessed multiple policies). Direct provision policies, which largely targeted fruits and vegetables, increased consumption of fruits by 0.27 servings/d (n = 15 estimates (95%CI: 0.17, 0.36)) and combined fruits and vegetables by 0.28 servings/d (n = 16 (0.17, 0.40)); with a slight impact on vegetables (n = 11; 0.04 (0.01, 0.08)), and no effects on total calories (n = 6; -56 kcal/d (-174, 62)). In interventions targeting water, habitual intake was unchanged (n = 3; 0.33 glasses/d (-0.27, 0.93)). Competitive food/beverage standards reduced sugar-sweetened beverage intake by 0.18 servings/d (n = 3 (-0.31, -0.05)); and unhealthy snacks by 0.17 servings/d (n = 2 (-0.22, -0.13)), without effects on total calories (n = 5; -79 kcal/d (-179, 21)). School meal standards (mainly lunch) increased fruit intake (n = 2; 0.76 servings/d (0.37, 1.16)) and reduced total fat (-1.49%energy; n = 6 (-2.42, -0.57)), saturated fat (n = 4; -0.93%energy (-1.15, -0.70)) and sodium (n = 4; -170 mg/d (-242, -98)); but not total calories (n = 8; -38 kcal/d (-137, 62)). In 17 studies evaluating adiposity, significant decreases were generally not identified; few studies assessed metabolic factors (blood lipids/glucose/pressure), with mixed findings. Significant sources of heterogeneity or publication bias were not identified. CONCLUSIONS: Specific school food environment policies can improve targeted dietary behaviors; effects on adiposity and metabolic risk require further investigation. These findings inform ongoing policy discussions and debates on best practices to improve childhood dietary habits and health

Fatty Acid-Depleted Albumin Induces the Formation of Echovirus A Particles

Picornavirus infection requires virus uncoating, associated with the production of 135S “A” particles and 80S empty particles from 160S mature virions, to release the RNA genome into the cell cytoplasm. Normal albumin inhibits this process. We now show that when depleted of fatty acids, albumin induces the formation of echovirus A particles

Coxsackievirus A9 VP1 Mutants with Enhanced or Hindered A Particle Formation and Decreased Infectivity

We have studied coxsackievirus A9 (CAV9) mutants that each have a single amino acid substitution in the conserved 29-PALTAVETGHT-39 motif of VP1 and a reduced capacity to produce infectious progeny virus. After uncoating, all steps in the infection cycle occurred according to the same kinetics as and similar efficiency to the wild-type virus. However, the particle/infectious unit ratio in the progeny was significantly increased. The differences were apparently due to altered stability of the capsid: there were mutant viruses with enhanced or hindered uncoating, and both of these characteristics were found to reduce fitness under standard passaging conditions. At 32°C the instable mutants had an advantage, while the wild-type and the most stable mutant grew poorly. When comparing the newly published CAV9 structure and the other enterovirus structures, we found that the PALTAVETGHT motif is always in exactly the same position, in a cavity formed by the 3 other capsid proteins, with the C terminus of VP4 between this motif and the RNA. In the 7 enterovirus structures determined to date, the most conserved residues of the studied motif have identical contacts to neighboring residues of VP2, VP3, and VP4. We conclude that (i) the mutations affect the uncoating step necessary for infection, resulting in an untimely or hindered externalization of the VP1 N terminus together with the VP4, and (ii) the reason for the studied motif being evolutionarily conserved is its role in maintaining an optimal balance between the protective stability and the functional flexibility of the capsid

Kinetic Analysis of the Effect of Poliovirus Receptor on Viral Uncoating: the Receptor as a Catalyst

We examined the role of soluble poliovirus receptor on the transition of native poliovirus (160S or N particle) to an infectious intermediate (135S or A particle). The viral receptor behaves as a classic transition state theory catalyst, facilitating the N-to-A conversion by lowering the activation energy for the process by 50 kcal/mol. In contrast to earlier studies which demonstrated that capsid-binding drugs inhibit thermally mediated N-to-A conversion through entropic stabilization alone, capsid-binding drugs are shown to inhibit receptor-mediated N-to-A conversion through a combination of enthalpic and entropic effects