Effects of consuming school meals enriched with fish powder on zinc status of school children in Malawi: study protocol for nourishing for knowledge: a randomized controlled trial

Abstract Background Zinc is an essential trace element that has a role in preventing mortality and morbidity, as well as in linear growth, brain development and neuron activity. According to Malawi’s 2015/16 micronutrient survey, 60 percent of school-aged children and younger adolescents were zinc deficient. Fish and other aquatic foods are rich in essential micronutrients like zinc, vitamins A and B12, iron, iodine and the long-chain omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid, all crucial for development, especially during early childhood and adolescence. However, these nutrients are often lacking from diets in Sub-Saharan Africa, contributing to persistent micronutrient deficiencies. The objective of this randomized controlled trial is to assess the impact of adding dried fish ( Engraulicypris sardella ) to cereal-based school meals on zinc status of children, measured through biomarker analysis, in selected pilot schools. Methods Two-armed randomized controlled trial where 272 adolescents in primary schools in Malawi of at least 10 years of age will be randomized to either receive the school meal as usual or school meal with 4 g of fish powder added, five days per week for one school term, lasting 14 weeks. Socioeconomic and demographic factors, dietary information and biological samples (dried blood spots) will be collected pre- and post-intervention and analyzed for zinc concentration as the primary outcome and other nutritional biomarkers as secondary outcomes. Discussion This study will provide knowledge on potential changes in zinc status when consuming locally-sourced fish powder made from dried small freshwater fish indigenous to Lake Malawi during adolescence. The results of the study will contribute to the understanding of the impact of a small quantity of fish consumed in school meals on the nutritional status of school-going children. Trial registration This study was registered in ClinicalTrials.gov (NCT07085871) on 17 July 2025. The full trial protocol and statistical analysis plan can be accessed through ClinicalTrials.gov.