PUBLIC HEALTH INTERVENTIONS ADDRESSING MICRONUTRIENT DEFICIENCIES AMONG CHILDREN WITH OBESITY IN THE UNITED KINGDOM: A SYSTEMATIC REVIEW AND NARRATIVE SYNTHESIS

Background: Childhood obesity can coexist with inadequate micronutrient intake or status, creating a double burden in which excess adiposity does not protect against undernutrition. In the United Kingdom, interventions have commonly targeted diet, physical activity and weight, but the extent to which they correct micronutrient deficiencies in children with obesity remains uncertain.
Objective: To synthesise evidence on the effectiveness of UK public health interventions that address micronutrient deficiency in children with obesity, while distinguishing direct micronutrient outcomes from indirect dietary and anthropometric outcomes.
Methods: CINAHL, PubMed, Scopus and Web of Science were searched between 19 and 31 December 2023 using terms for childhood obesity, micronutrients and public health interventions. Eligibility was framed around UK children aged 0-18 years, public health interventions, and measurable micronutrient or dietary outcomes. Study selection followed a PRISMA flow. Randomised and cohort studies were appraised with Critical Appraisal Skills Programme tools, and cross-sectional studies with the Centre for Evidence-Based Medicine checklist. Because designs, populations, interventions and outcomes were heterogeneous, findings were synthesised narratively.
Results: The searches identified 2,166 records; 16 studies were included after deduplication, screening and full-text assessment. Multicomponent family- and community-based programmes reported improvements in BMI z-score, waist circumference, physical activity and fruit and vegetable consumption, but one programme relied on pre-post data with substantial attrition. Large school-based cluster trials generally found no significant improvement in primary BMI, physical activity or fruit and vegetable outcomes, although some secondary behaviours improved. Dietary studies identified low vitamin D or iron intake, high free-sugar intake and socioeconomic variation. Crucially, the included evidence rarely enrolled only children with obesity and seldom measured correction of a confirmed biochemical micronutrient deficiency; consequently, much of the evidence was indirect for the review question.
Conclusion: The evidence supports comprehensive, family-engaged approaches to healthy eating and weight management, but it is insufficient to conclude that current UK public health interventions correct micronutrient deficiencies specifically among children with obesity. Future evaluations should define obesity consistently, measure baseline and follow-up micronutrient biomarkers alongside dietary intake, retain appropriate comparators and assess long-term effectiveness, equity and cost-effectiveness.