Effectiveness of school-based interventions in Europe to promote healthy nutrition in children and adolescents: systematic review of published and ‘grey’ literature

Two reviews included primary studies with a broader age range, but synthesised results for adolescents separately.

“Two reviews included primary studies with a broader age range, but synthesised results for adolescents separately [32, 34].”

Majority of the reviews (n = 14) evaluated multi-component interventions while three reviews evaluated only health education interventions.

“Majority of the reviews (n = 14) evaluated multi-component interventions [30–32, 34–40, 42–45] while three reviews evaluated only health education interventions [29, 33, 41].”

According to the JBI critical appraisal tool, 14 reviews scored high, two reviews scored moderate, and only one review scored low in terms of methodological quality.

“According to the JBI critical appraisal tool, 14 reviews scored high [30–32, 34–41, 43–45], two reviews scored moderate [33, 42], and only one review scored low [29] in terms of methodological quality (Table 2).”

Fifteen of the reviews used narrative synthesis and two included both meta-analysis and narrative synthesis.

“Fifteen of the reviews used narrative synthesis [29–43] and two included both meta-analysis and narrative synthesis [44, 45].”

The school environment components in the four inconclusive reviews included canteen modifications, food distributions, reduced price of fruits, social food marketing, staff trainings, loyalty programmes, gardening, postering, and vending machine modifications.

“The school environment components, working at the school system level, included canteen modifications [34, 39], food distributions [34], reduced price of fruits [44], social food marketing, staff trainings [39], loyalty programmes [34, 39], gardening, postering, and vending machine modifications [40].”

The outcomes in the four inconclusive reviews were measured by 24-h recall, FFQ, KAP, and 3-day food record.

“These outcomes were measured by 24-h recall [34, 39, 40, 44], FFQ [34, 40, 44], KAP [39], and 3-day food record [44].”

The contents of these family involvement components involved healthy eating lessons, incentives to purchase healthy foods, money rewards for purchasing healthy foods, cooking recipes, and healthy feeding to children.

“The contents involved healthy eating lessons [34, 39, 40, 44], incentives to purchase healthy foods [34, 39], money rewards for purchasing healthy foods [40], cooking recipes [39], and healthy feeding to children [40].”

The interventions in the four inconclusive reviews were informed by TPB, SCT, TTM, ASE model, principles of interactive technology, SLT, health promotion model (Pender's), SEM, DIT, control theory, information-motivation-behavioural skills model, and community-based capacity building approach.

“The interventions were informed by TPB [34, 39, 40, 44], SCT [39, 40, 44], TTM [39, 44], ASE model, principles of interactive technology, SLT, health promotion model (Pender’s) [44], SEM, DIT, control theory, information-motivation-behavioural skills model [39], and community-based capacity building approach [40].”

The contents of these healthy eating education components involved healthy eating lessons, food preparation, and taste testing.

“The contents involved healthy eating lessons [34, 39, 40, 44], food preparation, and taste testing [40].”

The family involvement components in the four inconclusive reviews included parents' meetings and workshops, distribution of newsletters, CDs, magazines, calendars, engaging parents in school nutrition council groups, and loyalty programmes.

“The family involvement components included parents’ meetings and workshops [34, 39, 40], distribution of newsletters, CDs, magazines, calendars [39, 40, 44], engaging parents in school nutrition council groups [39], and loyalty programmes [39, 40].”

The intervention duration in the four inconclusive reviews ranged from 12 h to three years, and only one review reported follow-up assessments from immediately to three years after the intervention.

“The intervention duration ranged from 12 h to three years [34, 39, 40, 44] and only one review reported follow up assessments occurred ranged from immediately to three years after the intervention [34, 39, 40, 44].”

The contents of these school environment components involved FV subscriptions, increased availability of healthy food in canteen, FV plantation, incentives to purchase healthy foods, staff training on healthy cooking, healthy eating posters around schools, enhanced lunch sessions with healthy meals, and replacing SSBs with healthy foods.

“The contents involved FV subscriptions [34, 40], increased availability of healthy food in canteen [34, 39], FV plantation [40], incentives to purchase healthy foods [34], staff training on healthy cooking healthy eating poster [39], healthy eating posters around schools [40], enhanced lunch sessions with healthy meals, and replacing SSBs with healthy foods [40].”

The healthy eating education components in the four inconclusive reviews included lectures, group discussions, games, distribution of materials via CDs, videos, emails, and text messages, blogs by a health coach, workshops for staff and students, and drama.

“The healthy eating education components included lectures [34, 39, 40], group discussions [40, 44], games [39, 44], distribution of materials via compact discs (CDs), videos, emails, and text messages, blogs by a health coach [44], workshops for staff and students [39], and drama [40].”

The studies assessed in the four inconclusive reviews employed RCTs (n = 39), non-RCTs (n = 16), cohort (n = 7), pre-post (n = 7), and quasi-experimental (n = 2) designs.

“The studies assessed in these four reviews employed RCTs (n = 39) [34, 39, 40, 44], non-RCTs (n = 16), cohort (n = 7), pre-post (n = 7) [34], and quasi-experimental (n = 2) designs [44].”

Four high-quality reviews (including 43 unique studies) reported inconclusive impacts on eating knowledge and behaviour, particularly for healthy eating knowledge, intake of FV, recommended fat, water, processed snacks, protein, fibre, and SSB.

“Four high-quality reviews (including unique 43 studies) reported “inconclusive” impacts on eating knowledge and behaviour, particularly in terms of healthy eating knowledge [44], intake of FV [34, 39, 40, 44], recommended fat [34, 39, 44], water [34, 40], processed snacks [40, 44], protein [40], fibre [44], and SSB [34].”

Effective intervention components focusing on children emphasise antecedents, particularly parental involvement in shaping eating behaviour and the importance of healthy food accessibility.

“Effective intervention components focusing on children emphasise antecedents, particularly parental involvement in shaping eating behaviour and the importance of healthy food accessibility [32, 34, 49].”