The Effects of Physical Activity Programs with Nutritional Supplementation in Children Until 12 Years Old Recruited from Schools: A Systematic Review of Randomized Controlled Trials

Background/Objectives: Combined physical activity and nutritional interventions may produce synergistic effects on child development, but evidence from school-based programs is still limited. This systematic review investigated the impact of physical activity programs with simultaneous nutritional supplementation in school-aged children. Methods: A systematic search was conducted across five databases (PubMed, ProQuest, SCOPUS, Web of Science, and SPORTDiscus) up to June 2025. Randomized controlled trials examining combined physical activity and nutritional supplementation interventions in children aged 5-12 years recruited from schools were included. Methodological quality was rated using the Physiotherapy Evidence Database (PEDro) scale. Results: Thirteen studies (n = 3967 participants) were eligible, with program lengths ranging from 2 weeks to 24 months. Methodological quality ranged from fair to good (PEDro scores: 4 to 7/10). Combined interventions showed greater benefits than single interventions. For bone health, 2-3% higher increases in bone mineral content at loaded sites were reported with exercise combined with calcium supplementation. Body composition improvements included significant reductions in fat mass and increases in fat-free mass, with effects most pronounced in girls and slow-growing children. Motor performance, academic achievement, and sleep quality also improved with combined approaches. Effects were consistently greatest in children with baseline micronutrient deficiencies or slower growth velocity. Conclusions: School-based programs combining moderate-to-high impact physical activity with targeted nutritional supplementation yield synergistic health benefits in children. Brief interventions (2-3 sessions/week, <= 60 min) appear sufficient when adequate micronutrient provision is ensured, supporting implementation feasibility within educational settings.