Efficacy of Iron-Rich Snacks in Improving Iron Status Among Adolescent Girls (10‒19 Years): A Systematic Review

Iron deficiency anaemia (IDA) is the most common form of anaemia and the leading cause of years lived with disabilities (YLD) and disability-adjusted life years (DALYs) among adolescents. Recently, various iron-rich snacks have been developed as interventions to improve iron status among adolescents. This review aimed to evaluate the efficacy of natural, non-commercially fortified iron-rich snacks in improving iron status among adolescent girls aged 10-19 years. A systematic review of randomized controlled trials and quasi-experiments was conducted, focusing on iron status indicators including hemoglobin (Hb), serum ferritin (SF), transferrin saturation (TSAT), and soluble transferrin receptors (sTfR). Searches were performed in PubMed, ScienceDirect, EBSCO, Research4Life, and Google Scholar. Risk of bias was assessed using Cochrane tools, and study quality was evaluated with GRADE. Ten studies (five RCTs and five quasi-experiments) involving 24 to 211 participants were included. Nine studies had moderate risk of bias, mainly due to performance, detection, and reporting issues; one had high selection bias. Iron content of snacks varied, with nine studies out of ten reported Hb increases ranging from 0.45 to 2.28 g/dL. Only one study reported improvements in serum iron (from 25.482 ± 0.036 g/dL to 41.511 ± 0.033 g/dL) and ferritin (from 10.827 ± 0.192 ng/mL to 14.016 ± 0.103 ng/mL). These results indicate the potential of locally developed snacks to improve iron and Hb levels in adolescents. This review synthesizes evidence on food-based interventions, focusing on natural, non-fortified iron-rich snacks for adolescent girls. The findings demonstrate promising potential for these snacks to improve iron status and haemoglobin concentrations, underscoring their value as culturally acceptable, cost-effective, and sustainable complement to existing nutrition strategies. Although results are promising, more rigorously designed trials with comprehensive iron biomarkers are needed to confirm efficacy and support integration into adolescent nutrition programs.