Effectiveness and Safety Profile of Oral Zinc Supplementation in Preterm or Low Birth Weight Infants: A Comprehensive Systematic Review from Developing Countries’ Perspectives

Background: Zinc is essential for physiological functions, however preterm and/or low birth weight (LBW) infants have low zinc storage. This study aims to assess the effectiveness of oral zinc supplementation on preterm and LBW infants in Low and Middle-Income Countries (LMICs), as evidence on its health outcomes remains unclear. Objectives: Zinc is essential for physiological functions in preterm and/or low birth weight (LBW) infants. However, recent guideline from WHO states oral zinc supplementation as a conditional recommendation with low certainty evidence. This study aims to assess the effectiveness and safety profile of oral zinc supplementation on preterm and LBW infants in developing countries, as evidence on its health outcomes remains unclear. Methods: This study was conducted according to PRISMA 2020. We used PubMed and ScienceDirect to conduct a literature search published until January 2025. Results: A total of 3071 preterm or LBW infants from 9 RCTs were included; 1589 of them received oral zinc treatment. Nine studies reported better growth parameters in the zinc group. The morbidities, such as BPD, NEC, ROP, and IVH, also mortality rate were reported to be lower in the zinc group. Conclusions: Oral zinc administration in preterm infants has been shown to improve growth, reduce morbidity and mortality incidence.