The Role of Probiotics and Probiotic-Fortified Product Supplementation in Improving Nutritional Outcomes in Children under Five with Acute Malnutrition: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials Protocol

The Role of Probiotics and Probiotic-Fortified Product Supplementation in Improving Nutritional Outcomes in Children under Five with Acute Malnutrition: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials Protocol | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article The Role of Probiotics and Probiotic-Fortified Product Supplementation in Improving Nutritional Outcomes in Children under Five with Acute Malnutrition: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials Protocol Abiy Hailu Tikuneh, Eyob Ketema Bogale, Getalem Ayechew Beyene, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7228088/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 08 Dec, 2025 Read the published version in Systematic Reviews → Version 1 posted 5 You are reading this latest preprint version Abstract Background: Acute 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. Methods: This 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. Subgroup analyses (e.g., by strain, dosage, duration) and sensitivity analyses will address heterogeneity. Certainty of evidence 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 PRISMA2020 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: This protocol is registered with PROSPERO with Registration: ID CRD420251091133 Acute malnutrition Probiotics Severe acute malnutrition Moderate acute malnutrition Nutritional recovery Systematic review Meta-analysis Background Acute malnutrition encompassing Severe Acute Malnutrition (SAM) and Moderate Acute Malnutrition (MAM) remains one of the most urgent public health challenges globally, affecting approximately 45 million children under the age of five. Of these, an estimated 13.6 million suffer from SAM and over 31 million from MAM [1]. These conditions are associated with dramatically elevated risks of morbidity, mortality, impaired immune function, and delayed cognitive and physical development. Children with SAM, in particular, face an 11-fold higher risk of death than their well-nourished counterparts [2]. Although nutritional rehabilitation strategies such as Ready-to-Use Therapeutic Foods (RUTFs) for SAM and Fortified Blended Foods (FBFs) for MAM have improved survival, treatment outcomes often remain suboptimal. High rates of relapse and non-response persist, especially in resource-limited settings [3]. This has prompted calls for adjunctive strategies that address not only nutrient replacement but also the underlying biological dysfunctions associated with acute malnutrition. Emerging evidence has identified a pivotal role for the gut microbiota in the pathogenesis of SAM and MAM. Children with acute malnutrition commonly exhibit gut microbiota dysbiosis, compromised intestinal barrier integrity, chronic inflammation, and systemic immune suppression [4–6]. These disruptions can impair nutrient absorption and compromise the effectiveness of therapeutic feeding, potentially explaining poor recovery outcomes in some children [7]. Probiotics—defined as live microorganisms that confer health benefits when administered in adequate amounts [8]—offer a biologically plausible intervention to help restore gut homeostasis in malnourished children. Mechanistic studies suggest that probiotics may improve nutritional recovery through several pathways: modulating the composition of gut microbiota, enhancing mucosal barrier integrity [9], promoting nutrient uptake, and regulating immune responses via short-chain fatty acids (SCFAs) and other metabolites [7,10]. By targeting both microbial and host immune functions, probiotics have the potential to correct the multifactorial physiological impairments seen in malnourished children [11]. Despite growing interest, findings from randomized controlled trials (RCTs) assessing probiotic supplementation in SAM or MAM remain inconsistent and inconclusive [12–14]. This heterogeneity is likely due to variation in probiotic strains, formulations, dosing regimens, duration of intervention, and participant characteristics such as breastfeeding status, co-infections, and environmental hygiene. To date, no comprehensive systematic review and meta-analysis has rigorously evaluated the effect of probiotics or probiotic-fortified products on recovery outcomes in children under five with SAM or MAM. Previous reviews have focused largely on unrelated outcomes such as diarrheal incidence or lacked robust methodological frameworks [3,11,14]. Crucially, indicators central to recovery—such as weight gain, weight-for-height z-scores (WHZ), mid-upper arm circumference (MUAC), recovery rate, and time to nutritional rehabilitation have not been systematically analyzed. This systematic review and meta-analysis aims to address this critical evidence gap by synthesizing RCT evidence on the efficacy of probiotic and probiotic-fortified supplementation in improving key nutritional and clinical recovery outcomes in children under five with SAM or MAM. Subgroup analyses will explore potential effect modification based on strain type, dose, and intervention duration. The GRADE framework will be used to assess the overall certainty of the evidence. Ultimately, this review will inform integration of microbiota-targeted interventions into acute malnutrition management, contributing to the realization of Sustainable Development Goal 3 (Good Health and Well-being) through improved survival and recovery of vulnerable children in low-resource settings. Objective and Research Question (PICO Framework) Objective The aim of this systematic review and meta-analysis is to assess the effectiveness of probiotic supplementation including probiotic-fortified products in improving nutritional recovery outcomes among children under five years of age diagnosed with Severe Acute Malnutrition (SAM) or Moderate Acute Malnutrition (MAM), compared with standard therapeutic feeding or placebo. Specific objectives To evaluate the effect of probiotic supplementation on weight gain (g/kg/day) among children under five years with SAM or MAM. To assess the impact of probiotics on anthropometric indicators , specifically weight-for-height z-score (WHZ) and mid-upper arm circumference (MUAC) . To determine the effect of probiotic supplementation on time to nutritional recovery in children with acute malnutrition. To estimate the effect of probiotics on nutritional recovery rates , defined according to standard discharge criteria used in SAM and MAM treatment programs. To assess the methodological quality and certainty of the evidence using standardized risk of bias assessment tools (e.g., Cochrane Risk of Bias 2.0) and the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) approach. The review will address the following research question framed using the PICO (Population, Intervention, Comparator, Outcome) framework: Population: Children aged 0–59 months diagnosed with SAM or MAM according to world health organizations (WHO) criteria: Severe Acute Malnutrition (SAM): Defined as any of the following: Weight-for-height z-score (WHZ) < -3 SD based on WHO growth standards, Mid-upper arm circumference (MUAC) < 11.5 cm, Presence of bilateral pitting oedema. Moderate Acute Malnutrition (MAM): Defined as: WHZ between -3 and -2 SD, or MUAC between 11.5 cm and 12.5 cm, with no oedema. Intervention: Probiotic supplementation of any strain, dose, frequency, or duration, including: Single-strain or multi-strain probiotic formulations, Probiotic-fortified foods such as yogurt, milk, or Ready-to-Use Therapeutic Food (RUTF). Subgroup analyses will be conducted based on formulation type where data permit. Comparator: Placebo, Standard therapeutic feeding protocols without probiotic supplementation (e.g., RUTF alone), Usual care as defined by the study protocol. Outcomes: Primary Outcome: Weight gain (g/kg/day) during the intervention period. Secondary Outcomes: Weight-for-height z-score (WHZ), Mid-upper arm circumference (MUAC), Time to nutritional recovery, Recovery rate (percentage of children reaching nutritional recovery status based on study criteria). Review Questions: Among children under five with Severe or Moderate Acute Malnutrition, how does probiotic supplementation (including fortified products), compared to standard therapeutic feeding or placebo, affect weight gain, anthropometric indicators (WHZ, MUAC), time to recovery, and overall recovery rates? Methods Eligibility Criteria This review will include randomized controlled trials (RCTs), including cluster-RCTs, that assess the effect of probiotic supplementation on recovery outcomes among children aged 0–59 months diagnosed with Severe Acute Malnutrition (SAM) and/or Moderate Acute Malnutrition (MAM), using WHO standard definitions. SAM is defined as weight-for-height z-score (WHZ) < -3 SD, MUAC < 11.5 cm, or the presence of bilateral pitting oedema. MAM is defined as WHZ between -3 and -2 SD or MUAC between 11.5 and 12.5 cm without oedema. Studies will be included if they evaluate probiotic interventions (either single or multi-strain), administered via any form (capsule, sachet, fortified food) as a standalone product or integrated into nutritional products such as yogurt, milk, or Ready-to-Use Therapeutic Foods (RUTF). Comparators may include placebo, standard treatment without probiotics, or usual care. To be eligible, studies must report at least one of the following outcomes: weight gain (g/kg/day), WHZ, MUAC, recovery rate, or time to nutritional recovery. Only peer-reviewed RCTs conducted in clinical or community settings (e.g., hospitals, outpatient feeding programs, CMAM services) will be included. Studies must be published in English, with no strict limitation on publication year; however, studies published in the last ten years will be prioritized. Grey literature, unpublished manuscripts, and conference abstracts will be excluded unless sufficient extractable data are available. Eligible studies will be grouped based on intervention type (standalone vs. fortified), delivery method, setting, comparator, and outcome domain to facilitate subgroup or narrative synthesis where meta-analysis is not feasible. Exclusion criteria include studies involving populations outside the 0–59-month age group, those without a defined diagnosis of SAM/MAM, or studies assessing prebiotics, synbiotics, antibiotics, or multi-component interventions where the effect of probiotics cannot be isolated. Observational studies, reviews, editorials, case series/reports, animal/in vitro studies, and non-English publications will also be excluded. These restrictions are justified by the aim to ensure methodological rigor, reduce bias, and enhance the relevance and applicability of the review findings to clinical and programmatic decision-making in child malnutrition care. Information Sources and Data Retrieval Plan A comprehensive search strategy will be employed to identify relevant studies for this systematic review. The following electronic bibliographic databases will be searched: PubMed/MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL, Scopus, and Web of Science. Search strategies will use a combination of Medical Subject Headings (MeSH), EMTREE terms, and free-text keywords adapted to the syntax of each database, using Boolean operators and relevant filters. The search will be limited to English-language publications, and search dates and platforms will be recorded for transparency and reproducibility. Additional manual citation tracking (both backward and forward) will be conducted using Scopus and Web of Science, and reference lists of relevant studies and systematic reviews will be screened for additional eligible studies. To capture grey literature and unpublished or ongoing trials, we will search ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP), and the WHO Global Index Medicus, including regional databases such as AIM, IMEMR, and LILACS. Relevant websites such as those of the World Health Organization (WHO), UNICEF, and Centers for Disease Control and Prevention (CDC) will also be explored for technical reports and non-indexed documents. Manual searching of key journals and conference proceedings will supplement the electronic search. All information sources, search strategies, and dates of access will be documented and presented in supplementary material to ensure transparency and facilitate replication of the search. Search Strategy Components A structured, PICO-based search strategy was developed to comprehensively identify randomized controlled trials evaluating probiotic supplementation in children under five with acute malnutrition. Four keyword and MeSH-based thematic blocks will be combined using Boolean logic: Intervention : Terms such as probiotic , probiotic supplementation/therapy , specific strains ( Lactobacillus , Bifidobacterium ), and related MeSH headings (e.g., “Probiotics”[Mesh]). Population : Age- and condition-specific terms including child , infant , SAM , MAM , and MeSH terms like “Severe Acute Malnutrition”[Mesh]. Outcomes : Nutritional indicators— weight gain , WHZ , MUAC , recovery rate/time —supported by “Treatment Outcome”[Mesh] and “Nutrition Assessment”[Mesh]. Study design : RCT-specific terms, including “randomized controlled trial” and MeSH entry “Randomized Controlled Trials as Topic” [Mesh]. These blocks will be combined (OR within each block; AND across blocks) to capture relevant trials. Database-specific adaptations (e.g., MeSH for PubMed, EMTREE for Embase) will ensure optimized retrieval, and additional techniques such as truncation ( child ), exact phrases (“weight gain”), and expert synonyms will enhance sensitivity and specificity. Full database-specific search strategie for Pub Med and detailed keyword structures are provided in Annexes 1–3. The complete search syntax for PubMed is included in an annex. Equivalent strategies will be tailored to other databases (Embase, CENTRAL, CINAHL, Scopus, Web of Science), with all search strings, platforms, and dates documented in the supplementary materials for transparency and reproducibility. PRISMA-Compliant Documentation This systematic review and meta-analysis will adhere to the PRISMA 2020 guidelines to ensure transparency, methodological rigor, and reproducibility. A structured and well-documented search process will be implemented and reported accordingly. Search strategies for each database will be individually developed, using platform-specific syntax and appropriate Boolean combinations. Complete search strings, along with search dates, database coverage periods, and applied filters (e.g., language restrictions to English and study design limited to RCTs), will be included in a supplementary file. All sources accessed, including clinical trial registries and grey literature repositories, will be documented with corresponding URLs and access dates. Search results will be exported to Zotero and Mendeley for citation management and then imported into systematic review software such as Rayyan for screening and deduplication. Duplicate records will be identified using both automated and manual approaches, with a deduplication log maintained. Title and abstract screening, followed by full-text eligibility review, will be conducted independently by two reviewers, with discrepancies resolved by consensus or third-party adjudication. The overall study selection process will be visualized using a PRISMA 2020 flow diagram (annexed), which will detail the number of records identified, screened, excluded (with reasons), and included in the final review. This approach ensures clarity in reporting and facilitates future review updates. Study Selection Process The study selection process will follow a systematic and transparent approach in accordance with the PRISMA 2020 guidelines to minimize bias and ensure reproducibility. All records retrieved from database and grey literature searches will be initially exported into Zotero and Mendeley for organization, then imported into Rayyan (or Covidence) to facilitate the screening process. Duplicate entries will be removed using software algorithms and verified manually, with the number of duplicates removed clearly documented. Two independent reviewers will perform title and abstract screening based on predefined inclusion criteria. Irrelevant studies will be excluded, and any discrepancies will be resolved through discussion or by involving a third reviewer. Full-text articles will then be retrieved for potentially eligible records. These will be assessed independently by the same reviewers, with reasons for exclusion recorded during full-text screening. Studies that fulfill all eligibility criteria will be included in the qualitative synthesis. Those reporting adequate outcome data will be considered for quantitative meta-analysis. The final study list will undergo sensitivity checks to ensure completeness, and known key studies will be verified for inclusion. Any refinement of search strategies will be documented as part of the review audit trail. The PRISMA 2020 flow diagram will illustrate the number of records identified, screened, excluded (with reasons), and ultimately included. All search strategies, database-specific syntax, search logs, and citation exports will be documented and annexed to support transparency and replicability of the review process. Data Extraction Process A standardized and pretested data extraction form will be used to ensure systematic and consistent data collection across all included studies. The form, developed in Microsoft Excel, is designed to capture all relevant information aligned with the objectives of the review and to facilitate narrative synthesis and potential meta-analysis. It will be pilot-tested on a sample of 3–5 studies by two independent reviewers, with necessary revisions made to improve clarity and reliability before full implementation. The final version will be annexed to the protocol. Data will be independently extracted by two reviewers, with discrepancies resolved through discussion or consultation with a third reviewer. Extracted data will be stored securely in a centralized system, and final entries will be verified for accuracy and completeness. The following data elements will be extracted: Study Identification : Author(s), publication year, article title, journal name, and country of study. Study Characteristics : Study design (e.g., RCT), setting (e.g., hospital, outpatient, community), sample size, and duration of follow-up. Population Details : Age range, sex distribution, sample sizes for intervention and control groups, inclusion/exclusion criteria, and baseline nutritional status (e.g., WHZ, MUAC). Intervention Characteristics : Type and strain(s) of probiotics, number of strains, dosage, frequency, duration, delivery form (e.g., capsule, food-fortified), route of administration, and any co-interventions (e.g., RUTF, micronutrients). Comparator Details : Type of control used (placebo, standard care, or no treatment), with description of its composition and mode of delivery. Outcomes : Primary and secondary outcomes including weight gain (g/kg/day), WHZ, MUAC, time to recovery, recovery rate, adverse events, and mortality. Risk of Bias : Elements such as randomization, allocation concealment, blinding, completeness of data, selective reporting, and other potential sources of bias. Additional Notes : Funding sources, conflicts of interest, and any clarifications needed (e.g., potential contact with authors for missing data). All data will be managed electronically and tracked using version-controlled files. A data extraction log will be maintained for transparency, and the completed dataset will serve as the basis for synthesis and quality appraisal. Data Synthesis and Meta-Analysis A meta-analysis (quantitative analysis) will be conducted if the included studies are sufficiently homogeneous in terms of participants, interventions, comparators, and outcomes. The primary method of synthesis will be a quantitative meta-analysis. For continuous outcomes (e.g., WHZ, MUAC, duration of recovery), the pooled effect sizes will be reported as either Mean Differences (MD) when outcome measures are reported on the same scale, or Standardized Mean Differences (SMD) when studies use different instruments or scales. For dichotomous outcomes (e.g., proportion recovered, mortality), the results will be synthesized using Risk Ratios (RR) or Odds Ratios (OR), each with corresponding 95% confidence intervals (CIs). All meta-analyses will be conducted using a random-effects model to account for expected variability across studies. Where appropriate, subgroup and sensitivity analyses will be carried out to explore potential sources of heterogeneity. If meta-analysis is not feasible, a narrative synthesis will be provided, structured around intervention types, populations, outcome domains, and methodological quality. Note for Meta-Analysis: Continuous outcomes (e.g., WHZ, MUAC, time to recovery) will be pooled using Mean Difference (MD) if reported on the same scale, or Standardized Mean Difference (SMD) if different tools or scales are used. Dichotomous outcomes (e.g., recovery rate) will be pooled using Risk Ratio (RR) or Odds Ratio (OR) with 95% Confidence Intervals. Heterogeneity Assessment Statistical heterogeneity among the included studies will be assessed using both the Chi-square (Cochran’s Q) test and the I² statistic. A p-value less than 0.10 in the Q-test will be considered indicative of statistically significant heterogeneity. The I² statistic will quantify the percentage of variability in effect estimates due to heterogeneity rather than chance, with the following thresholds used for interpretation: 75%: high heterogeneity If substantial heterogeneity is detected (defined as I² > 50% or p < 0.10 on the Q-test), potential sources will be explored through predefined subgroup and sensitivity analyses. A random-effects model will be used as the default meta-analytic approach to account for expected variability across studies. Subgroup Analysis To explore potential sources of heterogeneity and assess whether specific factors modify the effect of probiotic supplementation on nutritional recovery in children under five with acute malnutrition, subgroup analyses will be conducted where data permit. The predefined subgroups include: Type or strain of probiotic administered (e.g., Lactobacillus, Bifidobacterium, Saccharomyces) Duration of supplementation (short-term [<4 weeks] vs long-term [≥4 weeks]) Baseline severity of wasting (e.g., categorized by MUAC, WHZ, or presence of SAM vs MAM) Effect sizes will be compared across subgroups using stratified meta-analysis. Where sufficient studies are available (≥10 per subgroup), meta-regression will be conducted to statistically assess subgroup differences. These analyses will help identify whether specific probiotic regimens or patient characteristics are associated with improved outcomes. The results of subgroup analyses will be interpreted with caution due to the observational nature of between-study comparisons Sensitivity Analysis Sensitivity analyses will be conducted to evaluate the robustness of the main findings. These will include: Excluding studies assessed as having a high risk of bias Excluding studies with small sample sizes (e.g., n < 50) Comparing pooled effect estimates using fixed-effect versus random-effects models examining the impact of small or outlier or influential studies. These techniques will help assess whether the findings are dependent on methodological or sample-specific factors. If results remain consistent across these analyses, the findings will be interpreted as robust and reliable. Assessment of Publication Bias To evaluate potential publication bias, funnel plots will be generated based on the number of studies will be included in the analysis. The rule is "If ≥10 studies are included in the meta-analysis; funnel plots will be visually inspected for asymmetry to assess potential publication bias." In addition, formal statistical assessments will be performed using Egger’s regression test and Begg’s rank correlation test to statistically evaluate funnel plot asymmetry, where applicable. A p-value less than 0.05 will be considered indicative of potential publication bias." A symmetrical funnel plot and non-significant test results will be interpreted as indicating a low likelihood of publication bias. Where publication bias is suspected, its potential impact on the overall evidence will be discussed in the interpretation of findings and in the GRADE assessment. Confidence in Cumulative Evidence The GRADE (Grading of Recommendations Assessment, Development and Evaluation ) approach will be used to assess the overall certainty of the evidence across studies for each primary outcome across included studies. The quality of evidence will be graded as High , Moderate , Low , or Very Low , based on the following five domains: Risk of bias Inconsistency of results Indirectness of evidence Imprecision of estimates Potential for publication bias A summary of findings (SoF) table will be presented using GRADEpro software. Ethics and Dissemination As this review involves the synthesis of data from previously published studies and does not involve the collection of primary data or direct contact with human participants, ethical approval is not required . The findings will be submitted for publication in a peer-reviewed scientific journal and disseminated through presentations at relevant academic and professional conferences. Amendments Any amendments to this protocol will be documented and updated in the PROSPERO registry. A detailed record of all changes, including the rationale and date of each amendment, will be maintained to ensure transparency and reproducibility Declarations Ethics approval and consent to participate: Not applicable. This study is a protocol for a systematic review and meta-analysis and does not involve the collection of primary data from human participants. Therefore, ethical approval and informed consent are not required. Consent for Publication: Not applicable. This manuscript does not contain any individual person’s data in any form (including individual details, images, or videos), and therefore, consent for publication is not required. Availability of Data and Materials: Not applicable. This is a protocol for a systematic review and meta-analysis, and no primary data will be collected or generated. Competing Interests: The authors declare that they have no competing interests. Funding: This research received no specific grant or financial support from any funding agency in the public, commercial, or not-for-profit sectors. Authors’ Contributions: Abiy Hailu Tikuneh (AHT) is the corresponding author and serves as the principal investigator and lead author of this systematic review and meta-analysis. He conceptualized the study, developed the protocol, and designed the overall methodology. AHT will oversee all stages of the review process, including the formulation of the research questions, literature search strategy, quality appraisal, data synthesis, and interpretation of findings. He will also take the lead in drafting, revising, and finalizing the manuscript for publication. Eyob Ketema Bogale (EKB) and Getalem Ayechew Beyene (GAB) will contribute significantly to the screening and selection of studies, data extraction, and data analysis phases of the review. They will independently apply inclusion and exclusion criteria, extract relevant data from eligible studies, and support the statistical analysis and interpretation in collaboration with the lead author. EKB and GAB will also assist in preparing sections of the manuscript and reviewing it for intellectual content. Dr. Amare Deribew (AD) is the senior researcher and will provide methodological oversight and expert guidance throughout the review process. He will critically review the protocol, support the resolution of discrepancies at each stage of the review, and contribute to the interpretation of the results. Dr. Deribew will also participate in reviewing and refining the final manuscript to ensure scientific rigor and clarity. All authors have read and approved the final version of this protocol and agree to be accountable for all aspects of the work, ensuring that questions related to the accuracy or integrity of any part of the study are appropriately investigated and resolved. Acknowledgements: We would like to express my sincere gratitude to Bahir-Dar University School of Public Health, College of Medicine and Health Science’s department of nutrition and dietetics for the support provisions of learning environment that enabled me, gave me the opportunity and encourage me to share responsibility and commitment in advancing evidence-based nutrition and public health practice References UNICEF, WHO. Joint child mal nutrition estimates – levels and trends – 2023 edition. Geneva: WHO/UNICEF; 2023. Available from: https://data.unicef.org/topic/nutrition/malnutrition/ Black RE, Allen LH, Bhutta ZA, et al. Maternal and child undernutrition: global and regional exposures and health consequences. Lancet . 2008;371(9608):243–60. Lenters LM, Wazny K, Webb P, Ahmed T, Bhutta ZA. Treatment of severe and moderate acute malnutrition in low- and middle-income settings: a systematic review, meta-analysis and Delphi process. BMC Public Health . 2013;13(Suppl 3):S23. 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BMJ . 2021;372:n71 Supplementary Files Annexes.docx Cite Share Download PDF Status: Published Journal Publication published 08 Dec, 2025 Read the published version in Systematic Reviews → Version 1 posted Editorial decision: Major revision 30 Sep, 2025 Reviewers agreed at journal 13 Aug, 2025 Reviewers invited by journal 13 Aug, 2025 Editor assigned by journal 07 Aug, 2025 First submitted to journal 27 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7228088","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":499946923,"identity":"f7e67f4a-c301-4f0a-90dd-2702c6491ca0","order_by":0,"name":"Abiy Hailu Tikuneh","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA40lEQVRIiWNgGAWjYBACAwbGxgMMDAd4GJiZgTSDhAwxWhogWtjZEkBaeIjQAlQPRvw8IDYDYS3m7IcbDvPU3JExOMzz+dWNGgugdYePbsCnxbInEajl2DMeg8O826xzjgEdxpOWdgOvww6AtLAdBmsxzmEDapHgMcOv5fxDoJZ/IC08z4xz/hGj5QbQFt42sBbmx7ltRGl52HBwbt8zHsnDbGbMuX0SPGwE/XI+/eGDN9/u2POdP/z4c863Ojl+9sPH8GqBA4UDDGwSIAYbUcpBQL6BgfkD0apHwSgYBaNgRAEAPDNOu6je6JEAAAAASUVORK5CYII=","orcid":"https://orcid.org/0009-0008-4981-8520","institution":"Bahir Dar University College of Medical and Health Sciences","correspondingAuthor":true,"prefix":"","firstName":"Abiy","middleName":"Hailu","lastName":"Tikuneh","suffix":""},{"id":499946924,"identity":"7e591620-a81d-404c-b40a-cc9fe8684f51","order_by":1,"name":"Eyob Ketema Bogale","email":"","orcid":"","institution":"Bahir Dar University College of Medical and Health Sciences","correspondingAuthor":false,"prefix":"","firstName":"Eyob","middleName":"Ketema","lastName":"Bogale","suffix":""},{"id":499946925,"identity":"6a319813-237f-41dc-93d6-133aa62206c1","order_by":2,"name":"Getalem Ayechew Beyene","email":"","orcid":"","institution":"University of Gondar College of Medicine and Health Sciences","correspondingAuthor":false,"prefix":"","firstName":"Getalem","middleName":"Ayechew","lastName":"Beyene","suffix":""},{"id":499946926,"identity":"e066ea16-af6e-446f-9923-81b54d2db0c1","order_by":3,"name":"Amare Deribew Taddege","email":"","orcid":"","institution":"Bahir Dar University College of Medical and Health Sciences","correspondingAuthor":false,"prefix":"","firstName":"Amare","middleName":"Deribew","lastName":"Taddege","suffix":""}],"badges":[],"createdAt":"2025-07-27 19:46:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7228088/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7228088/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s13643-025-03013-9","type":"published","date":"2025-12-08T15:57:56+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":98245202,"identity":"06999a73-3fe3-4284-9dd5-8a2d56123d22","added_by":"auto","created_at":"2025-12-15 16:17:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":960357,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7228088/v1/bdee0d10-1b05-4530-aa11-ba8fde903204.pdf"},{"id":89544293,"identity":"b809bce2-8fca-4578-8462-d9beab6d0cb8","added_by":"auto","created_at":"2025-08-21 06:58:40","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":63810,"visible":true,"origin":"","legend":"","description":"","filename":"Annexes.docx","url":"https://assets-eu.researchsquare.com/files/rs-7228088/v1/b36f1c3fc58cdd975c97f851.docx"}],"financialInterests":"","formattedTitle":"The Role of Probiotics and Probiotic-Fortified Product Supplementation in Improving Nutritional Outcomes in Children under Five with Acute Malnutrition: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials Protocol","fulltext":[{"header":"Background","content":"\u003cp\u003eAcute malnutrition encompassing Severe Acute Malnutrition (SAM) and Moderate Acute Malnutrition (MAM) remains one of the most urgent public health challenges globally, affecting approximately 45 million children under the age of five. Of these, an estimated 13.6 million suffer from SAM and over 31 million from MAM [1]. These conditions are associated with dramatically elevated risks of morbidity, mortality, impaired immune function, and delayed cognitive and physical development. Children with SAM, in particular, face an 11-fold higher risk of death than their well-nourished counterparts [2].\u003c/p\u003e\n\u003cp\u003eAlthough nutritional rehabilitation strategies such as Ready-to-Use Therapeutic Foods (RUTFs) for SAM and Fortified Blended Foods (FBFs) for MAM have improved survival, treatment outcomes often remain suboptimal. High rates of relapse and non-response persist, especially in resource-limited settings [3]. This has prompted calls for adjunctive strategies that address not only nutrient replacement but also the underlying biological dysfunctions associated with acute malnutrition.\u003c/p\u003e\n\u003cp\u003eEmerging evidence has identified a pivotal role for the gut microbiota in the pathogenesis of SAM and MAM. Children with acute malnutrition commonly exhibit gut microbiota dysbiosis, compromised intestinal barrier integrity, chronic inflammation, and systemic immune suppression [4\u0026ndash;6]. These disruptions can impair nutrient absorption and compromise the effectiveness of therapeutic feeding, potentially explaining poor recovery outcomes in some children [7].\u003c/p\u003e\n\u003cp\u003eProbiotics\u0026mdash;defined as live microorganisms that confer health benefits when administered in adequate amounts [8]\u0026mdash;offer a biologically plausible intervention to help restore gut homeostasis in malnourished children. Mechanistic studies suggest that probiotics may improve nutritional recovery through several pathways: modulating the composition of gut microbiota, enhancing mucosal barrier integrity [9], promoting nutrient uptake, and regulating immune responses via short-chain fatty acids (SCFAs) and other metabolites [7,10]. By targeting both microbial and host immune functions, probiotics have the potential to correct the multifactorial physiological impairments seen in malnourished children [11].\u003c/p\u003e\n\u003cp\u003eDespite growing interest, findings from randomized controlled trials (RCTs) assessing probiotic supplementation in SAM or MAM remain inconsistent and inconclusive [12\u0026ndash;14]. This heterogeneity is likely due to variation in probiotic strains, formulations, dosing regimens, duration of intervention, and participant characteristics such as breastfeeding status, co-infections, and environmental hygiene.\u003c/p\u003e\n\u003cp\u003eTo date, no comprehensive systematic review and meta-analysis has rigorously evaluated the effect of probiotics or probiotic-fortified products on recovery outcomes in children under five with SAM or MAM. Previous reviews have focused largely on unrelated outcomes such as diarrheal incidence or lacked robust methodological frameworks [3,11,14]. Crucially, indicators central to recovery\u0026mdash;such as weight gain, weight-for-height z-scores (WHZ), mid-upper arm circumference (MUAC), recovery rate, and time to nutritional rehabilitation have not been systematically analyzed.\u003c/p\u003e\n\u003cp\u003eThis systematic review and meta-analysis aims to address this critical evidence gap by synthesizing RCT evidence on the efficacy of probiotic and probiotic-fortified supplementation in improving key nutritional and clinical recovery outcomes in children under five with SAM or MAM. Subgroup analyses will explore potential effect modification based on strain type, dose, and intervention duration. The GRADE framework will be used to assess the overall certainty of the evidence. Ultimately, this review will inform integration of microbiota-targeted interventions into acute malnutrition management, contributing to the realization of Sustainable Development Goal 3 (Good Health and Well-being) through improved survival and recovery of vulnerable children in low-resource settings.\u003c/p\u003e\n\u003ch2 id=\"_Toc204542906\"\u003eObjective and Research Question (PICO Framework)\u003c/h2\u003e\n\u003ch2 id=\"_Toc204542907\"\u003eObjective\u0026nbsp;\u003c/h2\u003e\n\u003cp\u003eThe aim of this systematic review and meta-analysis is to assess the effectiveness of probiotic supplementation including probiotic-fortified products in improving nutritional recovery outcomes among children under five years of age diagnosed with Severe Acute Malnutrition (SAM) or Moderate Acute Malnutrition (MAM), compared with standard therapeutic feeding or placebo.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSpecific objectives\u003c/strong\u003e\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003eTo evaluate the effect of probiotic supplementation on \u003cstrong\u003eweight gain (g/kg/day)\u003c/strong\u003e among children under five years with SAM or MAM.\u003c/li\u003e\n \u003cli\u003eTo assess the impact of probiotics on \u003cstrong\u003eanthropometric indicators\u003c/strong\u003e, specifically \u003cstrong\u003eweight-for-height z-score (WHZ)\u003c/strong\u003e and \u003cstrong\u003emid-upper arm circumference (MUAC)\u003c/strong\u003e.\u003c/li\u003e\n \u003cli\u003eTo determine the effect of probiotic supplementation on \u003cstrong\u003etime to nutritional recovery\u003c/strong\u003e in children with acute malnutrition.\u003c/li\u003e\n \u003cli\u003eTo estimate the effect of probiotics on \u003cstrong\u003enutritional recovery rates\u003c/strong\u003e, defined according to standard discharge criteria used in SAM and MAM treatment programs.\u003c/li\u003e\n \u003cli\u003eTo assess the \u003cstrong\u003emethodological quality\u003c/strong\u003e and \u003cstrong\u003ecertainty of the evidence\u003c/strong\u003e using standardized risk of bias assessment tools (e.g., Cochrane Risk of Bias 2.0) and the \u003cstrong\u003eGRADE\u003c/strong\u003e (Grading of Recommendations, Assessment, Development and Evaluations) approach.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThe review will address the following research question framed using the PICO (Population, Intervention, Comparator, Outcome) framework:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePopulation:\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Children aged 0\u0026ndash;59 months diagnosed with SAM or MAM according to world health organizations (WHO) criteria:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSevere Acute Malnutrition (SAM):\u003c/strong\u003e Defined as any of the following:\u003c/p\u003e\n\u003cul class=\"decimal_type\"\u003e\n \u003cli\u003eWeight-for-height z-score (WHZ) \u0026lt; -3 SD based on WHO growth standards,\u003c/li\u003e\n \u003cli\u003eMid-upper arm circumference (MUAC) \u0026lt; 11.5 cm,\u003c/li\u003e\n \u003cli\u003ePresence of bilateral pitting oedema.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eModerate Acute Malnutrition (MAM):\u003c/strong\u003e Defined as:\u003c/p\u003e\n\u003cul class=\"decimal_type\"\u003e\n \u003cli\u003eWHZ between -3 and -2 SD, or\u003c/li\u003e\n \u003cli\u003eMUAC between 11.5 cm and 12.5 cm, with no oedema.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eIntervention:\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;Probiotic supplementation of any strain, dose, frequency, or duration, including:\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003eSingle-strain or multi-strain probiotic formulations,\u003c/li\u003e\n \u003cli\u003eProbiotic-fortified foods such as yogurt, milk, or Ready-to-Use Therapeutic Food (RUTF).\u003cbr\u003e\u0026nbsp;Subgroup analyses will be conducted based on formulation type where data permit.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eComparator:\u003c/strong\u003e\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003ePlacebo,\u003c/li\u003e\n \u003cli\u003eStandard therapeutic feeding protocols without probiotic supplementation (e.g., RUTF alone),\u003c/li\u003e\n \u003cli\u003eUsual care as defined by the study protocol.\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eOutcomes:\u003c/strong\u003e\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003ePrimary Outcome:\u003c/strong\u003e\n \u003cul type=\"circle\"\u003e\n \u003cli\u003eWeight gain (g/kg/day) during the intervention period.\u003c/li\u003e\n \u003c/ul\u003e\n \u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eSecondary Outcomes:\u003c/strong\u003e\n \u003cul type=\"circle\"\u003e\n \u003cli\u003eWeight-for-height z-score (WHZ),\u003c/li\u003e\n \u003cli\u003eMid-upper arm circumference (MUAC),\u003c/li\u003e\n \u003cli\u003eTime to nutritional recovery,\u003c/li\u003e\n \u003cli\u003eRecovery rate (percentage of children reaching nutritional recovery status based on study criteria).\u003c/li\u003e\n \u003c/ul\u003e\n \u003c/li\u003e\n\u003c/ul\u003e\n\u003ch2 id=\"_Toc204542908\"\u003eReview Questions:\u003c/h2\u003e\n\u003cp\u003eAmong children under five with Severe or Moderate Acute Malnutrition, how does probiotic supplementation (including fortified products), compared to standard therapeutic feeding or placebo, affect weight gain, anthropometric indicators (WHZ, MUAC), time to recovery, and overall recovery rates?\u003c/p\u003e"},{"header":"Methods ","content":"\u003cp\u003e\u003cstrong\u003eEligibility Criteria\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis review will include randomized controlled trials (RCTs), including cluster-RCTs, that assess the effect of probiotic supplementation on recovery outcomes among children aged 0–59 months diagnosed with Severe Acute Malnutrition (SAM) and/or Moderate Acute Malnutrition (MAM), using WHO standard definitions. SAM is defined as weight-for-height z-score (WHZ) \u0026lt; -3 SD, MUAC \u0026lt; 11.5 cm, or the presence of bilateral pitting oedema. MAM is defined as WHZ between -3 and -2 SD or MUAC between 11.5 and 12.5 cm without oedema. Studies will be included if they evaluate probiotic interventions (either single or multi-strain), administered via any form (capsule, sachet, fortified food) as a standalone product or integrated into nutritional products such as yogurt, milk, or Ready-to-Use Therapeutic Foods (RUTF). Comparators may include placebo, standard treatment without probiotics, or usual care. To be eligible, studies must report at least one of the following outcomes: weight gain (g/kg/day), WHZ, MUAC, recovery rate, or time to nutritional recovery.\u003c/p\u003e\n\u003cp\u003eOnly peer-reviewed RCTs conducted in clinical or community settings (e.g., hospitals, outpatient feeding programs, CMAM services) will be included. Studies must be published in English, with no strict limitation on publication year; however, studies published in the last ten years will be prioritized. Grey literature, unpublished manuscripts, and conference abstracts will be excluded unless sufficient extractable data are available. Eligible studies will be grouped based on intervention type (standalone vs. fortified), delivery method, setting, comparator, and outcome domain to facilitate subgroup or narrative synthesis where meta-analysis is not feasible.\u003c/p\u003e\n\u003cp\u003eExclusion criteria include studies involving populations outside the 0–59-month age group, those without a defined diagnosis of SAM/MAM, or studies assessing prebiotics, synbiotics, antibiotics, or multi-component interventions where the effect of probiotics cannot be isolated. Observational studies, reviews, editorials, case series/reports, animal/in vitro studies, and non-English publications will also be excluded. These restrictions are justified by the aim to ensure methodological rigor, reduce bias, and enhance the relevance and applicability of the review findings to clinical and programmatic decision-making in child malnutrition care.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformation Sources and Data Retrieval Plan\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA comprehensive search strategy will be employed to identify relevant studies for this systematic review. The following electronic bibliographic databases will be searched: PubMed/MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL, Scopus, and Web of Science. Search strategies will use a combination of Medical Subject Headings (MeSH), EMTREE terms, and free-text keywords adapted to the syntax of each database, using Boolean operators and relevant filters. The search will be limited to English-language publications, and search dates and platforms will be recorded for transparency and reproducibility. Additional manual citation tracking (both backward and forward) will be conducted using Scopus and Web of Science, and reference lists of relevant studies and systematic reviews will be screened for additional eligible studies.\u003c/p\u003e\n\u003cp\u003eTo capture grey literature and unpublished or ongoing trials, we will search ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP), and the WHO Global Index Medicus, including regional databases such as AIM, IMEMR, and LILACS. Relevant websites such as those of the World Health Organization (WHO), UNICEF, and Centers for Disease Control and Prevention (CDC) will also be explored for technical reports and non-indexed documents. Manual searching of key journals and conference proceedings will supplement the electronic search. All information sources, search strategies, and dates of access will be documented and presented in supplementary material to ensure transparency and facilitate replication of the search.\u003c/p\u003e\n\u003cp id=\"_Toc204542912\"\u003e\u003cstrong\u003eSearch Strategy Components\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA structured, PICO-based search strategy was developed to comprehensively identify randomized controlled trials evaluating probiotic supplementation in children under five with acute malnutrition. Four keyword and MeSH-based thematic blocks will be combined using Boolean logic:\u003c/p\u003e\n\u003cul type=\"disc\"\u003e\n \u003cli\u003e\u003cstrong\u003eIntervention\u003c/strong\u003e: Terms such as \u003cem\u003eprobiotic\u003c/em\u003e, \u003cem\u003eprobiotic supplementation/therapy\u003c/em\u003e, specific strains (\u003cem\u003eLactobacillus\u003c/em\u003e, \u003cem\u003eBifidobacterium\u003c/em\u003e), and related MeSH headings (e.g., “Probiotics”[Mesh]).\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003ePopulation\u003c/strong\u003e: Age- and condition-specific terms including \u003cem\u003echild\u003c/em\u003e, \u003cem\u003einfant\u003c/em\u003e, \u003cem\u003eSAM\u003c/em\u003e, \u003cem\u003eMAM\u003c/em\u003e, and MeSH terms like “Severe Acute Malnutrition”[Mesh].\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eOutcomes\u003c/strong\u003e: Nutritional indicators—\u003cem\u003eweight gain\u003c/em\u003e, \u003cem\u003eWHZ\u003c/em\u003e, \u003cem\u003eMUAC\u003c/em\u003e, \u003cem\u003erecovery rate/time\u003c/em\u003e—supported by “Treatment Outcome”[Mesh] and “Nutrition Assessment”[Mesh].\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eStudy design\u003c/strong\u003e: RCT-specific terms, including “randomized controlled trial” and MeSH entry “Randomized Controlled Trials as Topic” [Mesh].\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThese blocks will be combined (OR within each block; AND across blocks) to capture relevant trials. Database-specific adaptations (e.g., MeSH for PubMed, EMTREE for Embase) will ensure optimized retrieval, and additional techniques such as truncation (\u003cem\u003echild\u003c/em\u003e), exact phrases (“weight gain”), and expert synonyms will enhance sensitivity and specificity. Full database-specific search strategie for Pub Med and detailed keyword structures are provided in Annexes 1–3.\u003c/p\u003e\n\u003cp\u003eThe complete search syntax for PubMed is included in an annex. Equivalent strategies will be tailored to other databases (Embase, CENTRAL, CINAHL, Scopus, Web of Science), with all search strings, platforms, and dates documented in the supplementary materials for transparency and reproducibility.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePRISMA-Compliant Documentation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis systematic review and meta-analysis will adhere to the PRISMA 2020 guidelines to ensure transparency, methodological rigor, and reproducibility. A structured and well-documented search process will be implemented and reported accordingly. Search strategies for each database will be individually developed, using platform-specific syntax and appropriate Boolean combinations. Complete search strings, along with search dates, database coverage periods, and applied filters (e.g., language restrictions to English and study design limited to RCTs), will be included in a supplementary file. All sources accessed, including clinical trial registries and grey literature repositories, will be documented with corresponding URLs and access dates.\u003c/p\u003e\n\u003cp\u003eSearch results will be exported to Zotero and Mendeley for citation management and then imported into systematic review software such as Rayyan for screening and deduplication. Duplicate records will be identified using both automated and manual approaches, with a deduplication log maintained. Title and abstract screening, followed by full-text eligibility review, will be conducted independently by two reviewers, with discrepancies resolved by consensus or third-party adjudication.\u003c/p\u003e\n\u003cp\u003eThe overall study selection process will be visualized using a PRISMA 2020 flow diagram (annexed), which will detail the number of records identified, screened, excluded (with reasons), and included in the final review. This approach ensures clarity in reporting and facilitates future review updates.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy Selection Process\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study selection process will follow a systematic and transparent approach in accordance with the PRISMA 2020 guidelines to minimize bias and ensure reproducibility. All records retrieved from database and grey literature searches will be initially exported into Zotero and Mendeley for organization, then imported into Rayyan (or Covidence) to facilitate the screening process. Duplicate entries will be removed using software algorithms and verified manually, with the number of duplicates removed clearly documented.\u003c/p\u003e\n\u003cp\u003eTwo independent reviewers will perform title and abstract screening based on predefined inclusion criteria. Irrelevant studies will be excluded, and any discrepancies will be resolved through discussion or by involving a third reviewer. Full-text articles will then be retrieved for potentially eligible records. These will be assessed independently by the same reviewers, with reasons for exclusion recorded during full-text screening.\u003c/p\u003e\n\u003cp\u003eStudies that fulfill all eligibility criteria will be included in the qualitative synthesis. Those reporting adequate outcome data will be considered for quantitative meta-analysis. The final study list will undergo sensitivity checks to ensure completeness, and known key studies will be verified for inclusion. Any refinement of search strategies will be documented as part of the review audit trail.\u003c/p\u003e\n\u003cp\u003eThe PRISMA 2020 flow diagram will illustrate the number of records identified, screened, excluded (with reasons), and ultimately included. All search strategies, database-specific syntax, search logs, and citation exports will be documented and annexed to support transparency and replicability of the review process.\u003c/p\u003e\n\u003cp id=\"_Toc204542913\"\u003eData Extraction Process\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA standardized and pretested data extraction form will be used to ensure systematic and consistent data collection across all included studies. The form, developed in Microsoft Excel, is designed to capture all relevant information aligned with the objectives of the review and to facilitate narrative synthesis and potential meta-analysis. It will be pilot-tested on a sample of 3–5 studies by two independent reviewers, with necessary revisions made to improve clarity and reliability before full implementation. The final version will be annexed to the protocol.\u003c/p\u003e\n\u003cp\u003eData will be independently extracted by two reviewers, with discrepancies resolved through discussion or consultation with a third reviewer. Extracted data will be stored securely in a centralized system, and final entries will be verified for accuracy and completeness.\u003c/p\u003e\n\u003cp\u003eThe following data elements will be extracted:\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy Identification\u003c/strong\u003e: Author(s), publication year, article title, journal name, and country of study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy Characteristics\u003c/strong\u003e: Study design (e.g., RCT), setting (e.g., hospital, outpatient, community), sample size, and duration of follow-up.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePopulation Details\u003c/strong\u003e: Age range, sex distribution, sample sizes for intervention and control groups, inclusion/exclusion criteria, and baseline nutritional status (e.g., WHZ, MUAC).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eIntervention Characteristics\u003c/strong\u003e: Type and strain(s) of probiotics, number of strains, dosage, frequency, duration, delivery form (e.g., capsule, food-fortified), route of administration, and any co-interventions (e.g., RUTF, micronutrients).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eComparator Details\u003c/strong\u003e: Type of control used (placebo, standard care, or no treatment), with description of its composition and mode of delivery.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eOutcomes\u003c/strong\u003e: Primary and secondary outcomes including weight gain (g/kg/day), WHZ, MUAC, time to recovery, recovery rate, adverse events, and mortality.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRisk of Bias\u003c/strong\u003e: Elements such as randomization, allocation concealment, blinding, completeness of data, selective reporting, and other potential sources of bias.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAdditional Notes\u003c/strong\u003e: Funding sources, conflicts of interest, and any clarifications needed (e.g., potential contact with authors for missing data).\u003c/p\u003e\n\u003cp\u003eAll data will be managed electronically and tracked using version-controlled files. A data extraction log will be maintained for transparency, and the completed dataset will serve as the basis for synthesis and quality appraisal.\u003c/p\u003e\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"},{"header":"Data Synthesis and Meta-Analysis","content":"\u003cp\u003eA meta-analysis (quantitative analysis) will be conducted if the included studies are sufficiently homogeneous in terms of participants, interventions, comparators, and outcomes. The primary method of synthesis will be a quantitative meta-analysis.\u003c/p\u003e\u003cul\u003e\n \u003cli\u003eFor continuous outcomes (e.g., WHZ, MUAC, duration of recovery), the pooled effect sizes will be reported as either \u003cstrong\u003eMean Differences (MD)\u003c/strong\u003e when outcome measures are reported on the same scale, or \u003cstrong\u003eStandardized Mean Differences (SMD)\u003c/strong\u003e when studies use different instruments or scales.\u003c/li\u003e\n \u003cli\u003eFor dichotomous outcomes (e.g., proportion recovered, mortality), the results will be synthesized using Risk Ratios (RR) or Odds Ratios (OR), each with corresponding 95% confidence intervals (CIs).\u003c/li\u003e\n \u003cli\u003eAll meta-analyses will be conducted using a \u003cstrong\u003erandom-effects model\u003c/strong\u003e to account for expected variability across studies. Where appropriate, subgroup and sensitivity analyses will be carried out to explore potential sources of heterogeneity.\u003c/li\u003e\n \u003cli\u003eIf meta-analysis is not feasible, a narrative synthesis will be provided, structured around intervention types, populations, outcome domains, and methodological quality.\u003c/li\u003e\n\u003c/ul\u003e\u003cp\u003e\u003cstrong\u003eNote for Meta-Analysis:\u003c/strong\u003e\u003c/p\u003e\u003cul\u003e\n \u003cli\u003eContinuous outcomes (e.g., WHZ, MUAC, time to recovery) will be pooled using Mean Difference (MD) if reported on the same scale, or Standardized Mean Difference (SMD) if different tools or scales are used.\u003c/li\u003e\n \u003cli\u003eDichotomous outcomes (e.g., recovery rate) will be pooled using Risk Ratio (RR) or Odds Ratio (OR) with 95% Confidence Intervals.\u003c/li\u003e\n\u003c/ul\u003e\u003cp id=\"_Toc204542915\"\u003eHeterogeneity Assessment\u003c/p\u003e\u003cp\u003eStatistical heterogeneity among the included studies will be assessed using both the Chi-square (Cochran’s Q) test and the I² statistic. A p-value less than 0.10 in the Q-test will be considered indicative of statistically significant heterogeneity. The I² statistic will quantify the percentage of variability in effect estimates due to heterogeneity rather than chance, with the following thresholds used for interpretation:\u003c/p\u003e\u003cul\u003e\n \u003cli\u003e\u0026lt;25%: low heterogeneity\u003c/li\u003e\n \u003cli\u003e25–75%: moderate heterogeneity\u003c/li\u003e\n \u003cli\u003e\u0026gt;75%: high heterogeneity\u003c/li\u003e\n\u003c/ul\u003e\u003cp\u003eIf substantial heterogeneity is detected (defined as I² \u0026gt; 50% or p \u0026lt; 0.10 on the Q-test), potential sources will be explored through predefined subgroup and sensitivity analyses. A random-effects model will be used as the default meta-analytic approach to account for expected variability across studies.\u003c/p\u003e\u003cp id=\"_Toc204542916\"\u003eSubgroup Analysis\u003c/p\u003e\u003cp\u003eTo explore potential sources of heterogeneity and assess whether specific factors modify the effect of probiotic supplementation on nutritional recovery in children under five with acute malnutrition, subgroup analyses will be conducted where data permit. The predefined subgroups include:\u003c/p\u003e\u003cul\u003e\n \u003cli\u003eType or strain of probiotic administered (e.g., Lactobacillus, Bifidobacterium, Saccharomyces)\u003c/li\u003e\n \u003cli\u003eDuration of supplementation (short-term [\u0026lt;4 weeks] vs long-term [≥4 weeks])\u003c/li\u003e\n \u003cli\u003eBaseline severity of wasting (e.g., categorized by MUAC, WHZ, or presence of SAM vs MAM)\u003c/li\u003e\n\u003c/ul\u003e\u003cp\u003eEffect sizes will be compared across subgroups using stratified meta-analysis. Where sufficient studies are available (≥10 per subgroup), meta-regression will be conducted to statistically assess subgroup differences. These analyses will help identify whether specific probiotic regimens or patient characteristics are associated with improved outcomes. The results of subgroup analyses will be interpreted with caution due to the observational nature of between-study comparisons\u003c/p\u003e\u003cp id=\"_Toc204542917\"\u003eSensitivity Analysis\u003c/p\u003e\u003cp\u003eSensitivity analyses will be conducted to evaluate the robustness of the main findings. These will include:\u003c/p\u003e\u003cul type=\"disc\"\u003e\n \u003cli\u003eExcluding studies assessed as having a high risk of bias\u003c/li\u003e\n \u003cli\u003eExcluding studies with small sample sizes (e.g., n \u0026lt; 50)\u003c/li\u003e\n \u003cli\u003eComparing pooled effect estimates using fixed-effect versus random-effects models\u003c/li\u003e\n \u003cli\u003eexamining the impact of small or outlier or influential studies.\u003c/li\u003e\n\u003c/ul\u003e\u003cp\u003eThese techniques will help assess whether the findings are dependent on methodological or sample-specific factors. If results remain consistent across these analyses, the findings will be interpreted as robust and reliable.\u003c/p\u003e\u003cp id=\"_Toc204542918\"\u003eAssessment of Publication Bias\u003c/p\u003e\u003cp\u003eTo evaluate potential publication bias, funnel plots will be generated based on the number of studies will be included in the analysis. The rule is \"If ≥10 studies are included in the meta-analysis; funnel plots will be visually inspected for asymmetry to assess potential publication bias.\" In addition, formal statistical assessments will be performed using Egger’s regression test and Begg’s rank correlation test to statistically evaluate funnel plot asymmetry, where applicable. A p-value less than 0.05 will be considered indicative of potential publication bias.\" A symmetrical funnel plot and non-significant test results will be interpreted as indicating a low likelihood of publication bias. Where publication bias is suspected, its potential impact on the overall evidence will be discussed in the interpretation of findings and in the GRADE assessment.\u003c/p\u003e\u003cp id=\"_Toc204542919\"\u003eConfidence in Cumulative Evidence\u003c/p\u003e\u003cp\u003eThe \u003cstrong\u003eGRADE (Grading of Recommendations Assessment, Development and Evaluation\u003c/strong\u003e\u003cstrong\u003e)\u003c/strong\u003e approach will be used to assess the overall certainty of the evidence across studies for each primary outcome across included studies. The quality of evidence will be graded as \u003cstrong\u003eHigh\u003c/strong\u003e, \u003cstrong\u003eModerate\u003c/strong\u003e, \u003cstrong\u003eLow\u003c/strong\u003e, or \u003cstrong\u003eVery Low\u003c/strong\u003e, based on the following five domains:\u003c/p\u003e\u003col start=\"1\" type=\"1\"\u003e\n \u003cli\u003eRisk of bias\u003c/li\u003e\n \u003cli\u003eInconsistency of results\u003c/li\u003e\n \u003cli\u003eIndirectness of evidence\u003c/li\u003e\n \u003cli\u003eImprecision of estimates\u003c/li\u003e\n \u003cli\u003ePotential for publication bias\u003c/li\u003e\n\u003c/ol\u003e\u003cp\u003eA summary of findings (SoF) table will be presented using GRADEpro software.\u003c/p\u003e\u003cp id=\"_Toc204542920\"\u003eEthics and Dissemination\u003c/p\u003e\u003cp\u003eAs this review involves the synthesis of data from previously published studies and does not involve the collection of primary data or direct contact with human participants, \u003cstrong\u003eethical approval is not required\u003c/strong\u003e. The findings will be submitted for publication in a peer-reviewed scientific journal and disseminated through presentations at relevant academic and professional conferences.\u003c/p\u003e\u003cp id=\"_Toc204542921\"\u003eAmendments\u003c/p\u003e\u003cp\u003eAny amendments to this protocol will be documented and updated in the \u003cstrong\u003ePROSPERO\u003c/strong\u003e registry. A detailed record of all changes, including the rationale and date of each amendment, will be maintained to ensure transparency and reproducibility\u003c/p\u003e"},{"header":"Declarations","content":"\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eEthics approval and consent to participate:\u003c/strong\u003e Not applicable. This study is a protocol for a systematic review and meta-analysis and does not involve the collection of primary data from human participants. Therefore, ethical approval and informed consent are not required.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eConsent for Publication:\u0026nbsp;\u003c/strong\u003eNot applicable. This manuscript does not contain any individual person\u0026rsquo;s data in any form (including individual details, images, or videos), and therefore, consent for publication is not required.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eAvailability of Data and Materials:\u0026nbsp;\u003c/strong\u003eNot applicable. This is a protocol for a systematic review and meta-analysis, and no primary data will be collected or generated.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eCompeting Interests:\u0026nbsp;\u003c/strong\u003eThe authors declare that they have no competing interests.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003eThis research received no specific grant or financial support from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eAuthors\u0026rsquo; Contributions:\u003c/strong\u003e\u0026nbsp;\u003col\u003e\n \u003cli\u003eAbiy Hailu Tikuneh (AHT) is the corresponding author and serves as the principal investigator and lead author of this systematic review and meta-analysis. He conceptualized the study, developed the protocol, and designed the overall methodology. AHT will oversee all stages of the review process, including the formulation of the research questions, literature search strategy, quality appraisal, data synthesis, and interpretation of findings. He will also take the lead in drafting, revising, and finalizing the manuscript for publication.\u003c/li\u003e\n \u003cli\u003eEyob Ketema Bogale (EKB) and Getalem Ayechew Beyene (GAB) will contribute significantly to the screening and selection of studies, data extraction, and data analysis phases of the review. They will independently apply inclusion and exclusion criteria, extract relevant data from eligible studies, and support the statistical analysis and interpretation in collaboration with the lead author. EKB and GAB will also assist in preparing sections of the manuscript and reviewing it for intellectual content.\u003c/li\u003e\n \u003cli\u003eDr. Amare Deribew (AD) is the senior researcher and will provide methodological oversight and expert guidance throughout the review process. He will critically review the protocol, support the resolution of discrepancies at each stage of the review, and contribute to the interpretation of the results. Dr. Deribew will also participate in reviewing and refining the final manuscript to ensure scientific rigor and clarity.\u003c/li\u003e\n \u003cli\u003eAll authors have read and approved the final version of this protocol and agree to be accountable for all aspects of the work, ensuring that questions related to the accuracy or integrity of any part of the study are appropriately investigated and resolved.\u003c/li\u003e\n \u003c/ol\u003e\n \u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements:\u003c/strong\u003e We would like to express my sincere gratitude to Bahir-Dar University School of Public Health, College of Medicine and Health Science\u0026rsquo;s department of nutrition and dietetics for the support provisions of learning environment that enabled me, gave me the opportunity and encourage me to share responsibility and commitment in advancing evidence-based nutrition and public health practice\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eUNICEF, WHO. Joint child mal nutrition estimates \u0026ndash; levels and trends \u0026ndash; 2023 edition. Geneva: WHO/UNICEF; 2023. Available from: https://data.unicef.org/topic/nutrition/malnutrition/\u003c/li\u003e\n\u003cli\u003eBlack RE, Allen LH, Bhutta ZA, et al. Maternal and child undernutrition: global and regional exposures and health consequences. \u003cem\u003eLancet\u003c/em\u003e. 2008;371(9608):243\u0026ndash;60.\u003c/li\u003e\n\u003cli\u003eLenters LM, Wazny K, Webb P, Ahmed T, Bhutta ZA. Treatment of severe and moderate acute malnutrition in low- and middle-income settings: a systematic review, meta-analysis and Delphi process. \u003cem\u003eBMC Public Health\u003c/em\u003e. 2013;13(Suppl 3):S23.\u003c/li\u003e\n\u003cli\u003eSubramanian S, Huq S, Yatsunenko T, et al. Persistent gut microbiota immaturity in malnourished Bangladeshi children. \u003cem\u003eNature\u003c/em\u003e. 2014;510(7505):417\u0026ndash;21.\u003c/li\u003e\n\u003cli\u003eMillion M, Angelakis E, Paul M, et al. Comparative meta-analysis of the effect of \u003cem\u003eLactobacillus\u003c/em\u003e species on weight gain in humans and animals. \u003cem\u003eMicrob Pathog\u003c/em\u003e. 2012;53(2):100\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eBlanton LV, Barratt MJ, Charbonneau MR, et al. Gut bacteria that prevent growth impairments transmitted by microbiota from malnourished children. \u003cem\u003eScience\u003c/em\u003e. 2016;351(6275):aad3311.\u003c/li\u003e\n\u003cli\u003eSalminen S, Collado MC, Endo A, et al. ISAPP consensus statement on the definition and scope of postbiotics. \u003cem\u003eNat Rev Gastroenterol Hepatol\u003c/em\u003e. 2021;18(9):649\u0026ndash;67.\u003c/li\u003e\n\u003cli\u003eRautava S, Luoto R, Salminen S, Isolauri E. Microbial contact during pregnancy, intestinal colonization and human disease. \u003cem\u003eNat Rev Gastroenterol Hepatol\u003c/em\u003e. 2012;9(10):565\u0026ndash;76.\u003c/li\u003e\n\u003cli\u003eBron PA, Kleerebezem M, Brummer RJ, et al. Can probiotics modulate human disease by impacting intestinal barrier function? \u003cem\u003eBr J Nutr\u003c/em\u003e. 2017;117(1):93\u0026ndash;107.\u003c/li\u003e\n\u003cli\u003eBinda S, Hill C, Johansen E, et al. Criteria to qualify microorganisms as \u0026quot;probiotic\u0026quot; for use in humans and animals. \u003cem\u003eJ Appl Microbiol\u003c/em\u003e. 2020;129(4):1276\u0026ndash;88.\u003c/li\u003e\n\u003cli\u003eKerac M, Mwangome M, McGrath M, et al. Probiotics and prebiotics for severe acute malnutrition: a systematic review. \u003cem\u003eMatern Child Nutr\u003c/em\u003e. 2019;15(3):e12728.\u003c/li\u003e\n\u003cli\u003eDang AT, Marsland BJ. Microbes, metabolites, and the gut\u0026ndash;lung axis. \u003cem\u003eMucosal Immunol\u003c/em\u003e. 2019;12(4):843\u0026ndash;50.\u003c/li\u003e\n\u003cli\u003eOnubi OJ, Poobalan AS, Dineen TE, Marais D, McNeill G. Effects of probiotics on child growth: a systematic review. \u003cem\u003eJ Health Popul Nutr\u003c/em\u003e. 2015;33(1):13.\u003c/li\u003e\n\u003cli\u003eAfolabi BM, Sola AO, Fakunle JB, et al. Probiotics for treatment of acute malnutrition in children: a systematic review and meta-analysis. \u003cem\u003eClin Nutr ESPEN\u003c/em\u003e. 2020;37:90\u0026ndash;101.\u003c/li\u003e\n\u003cli\u003ePage MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. \u003cem\u003eBMJ\u003c/em\u003e. 2021;372:n71\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"systematic-reviews","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sysr","sideBox":"Learn more about [Systematic Reviews](http://systematicreviewsjournal.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/sysr/default.aspx","title":"Systematic Reviews","twitterHandle":"@MedicalEvidence","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Acute malnutrition, Probiotics, Severe acute malnutrition, Moderate acute malnutrition, Nutritional recovery, Systematic review, Meta-analysis","lastPublishedDoi":"10.21203/rs.3.rs-7228088/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7228088/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAcute 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.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThis 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. Subgroup analyses (e.g., by strain, dosage, duration) and sensitivity analyses will address heterogeneity. Certainty of evidence will be assessed using the GRADE approach.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDiscussion:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThis will be the first systematic review to rigorously evaluate probiotic supplementation for both SAM and MAM populations using PRISMA2020 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.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSystematic Review Registration:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThis protocol is registered with PROSPERO with \u003c/em\u003e\u003cstrong\u003eRegistration: ID \u003c/strong\u003eCRD420251091133\u003c/p\u003e","manuscriptTitle":"The Role of Probiotics and Probiotic-Fortified Product Supplementation in Improving Nutritional Outcomes in Children under Five with Acute Malnutrition: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials Protocol","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-21 06:58:35","doi":"10.21203/rs.3.rs-7228088/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2025-10-01T03:23:49+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2025-08-13T12:16:48+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-13T12:04:30+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-07T06:29:28+00:00","index":"","fulltext":""},{"type":"submitted","content":"Systematic Reviews","date":"2025-07-27T15:45:58+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"systematic-reviews","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sysr","sideBox":"Learn more about [Systematic Reviews](http://systematicreviewsjournal.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/sysr/default.aspx","title":"Systematic Reviews","twitterHandle":"@MedicalEvidence","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"a362bcac-1159-4823-8076-b80ec674aa70","owner":[],"postedDate":"August 21st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-15T16:13:39+00:00","versionOfRecord":{"articleIdentity":"rs-7228088","link":"https://doi.org/10.1186/s13643-025-03013-9","journal":{"identity":"systematic-reviews","isVorOnly":false,"title":"Systematic Reviews"},"publishedOn":"2025-12-08 15:57:56","publishedOnDateReadable":"December 8th, 2025"},"versionCreatedAt":"2025-08-21 06:58:35","video":"","vorDoi":"10.1186/s13643-025-03013-9","vorDoiUrl":"https://doi.org/10.1186/s13643-025-03013-9","workflowStages":[]},"version":"v1","identity":"rs-7228088","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7228088","identity":"rs-7228088","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}