The role of probiotics and probiotic fortified products supplementation in improving nutritional outcomes in children under 5 with acute malnutrition: a systematic review and meta-analysis of randomized, controlled trials protocol.

backgroundAcute malnutrition, including severe acute malnutrition (SAM) and moderate acute malnutrition (MAM), affects over 45 million children under five globally and remains a leading cause of childhood morbidity and mortality. Despite therapeutic feeding programs using ready-to-use therapeutic foods (RUTFs) and fortified blended foods (FBFs), relapse and suboptimal treatment outcomes persist. Emerging evidence links gut microbiota dysbiosis to impaired nutrient absorption and immune function in malnourished children. Probiotic supplementation has been proposed as a strategy to restore microbial balance, enhance intestinal health, and improve nutritional recovery. However, clinical trial evidence remains inconsistent, particularly for children with MAM.

methodsThis protocol outlines a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating the effects of probiotic or probiotic-fortified product supplementation in children under five diagnosed with SAM or MAM. Databases to be searched include PubMed, Embase, CENTRAL, CINAHL, Web of Science, and Scopus, along with clinical trial registries. Eligible studies will compare probiotic interventions with placebo, standard care, or no treatment. Primary outcomes include weight gain, weight-for-height z-scores (WHZ), mid-upper arm circumference (MUAC), recovery rate, and time to nutritional recovery. Two reviewers will independently conduct study selection, data extraction, and risk of bias assessment using the Cochrane Risk of Bias 2.0 tool. Random-effects meta-analyses will be performed where appropriate. To explore potential sources of heterogeneity, we will perform subgroup analyses based on factors such as strain, dosage, and duration. Furthermore, sensitivity analyses will be used to test the robustness of the findings against various methodological assumptions and decisions. The overall certainty of the evidence for each outcome will be assessed using the GRADE approach. DISCUSSION: This will be the first systematic review to rigorously evaluate probiotic supplementation for both SAM and MAM populations using PRISMA 2020 guidelines and GRADE methodology. Strengths include a focus on high-quality RCTs, comprehensive search strategies, and transparent bias and evidence quality assessments. Limitations may include variability in probiotic strains, formulations, dosages, and outcome measures, as well as limited subgroup data. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD420251091133.