The interplay between malnutrition, persistent diarrhea, lactose intolerance, and food associated gut dysbiosis in children; a comprehensive review

Persistent diarrhea, lactose intolerance, and gut dysbiosis are major gastrointestinal conditions that worsen malnutrition in children, especially in low and middle-income countries. Due to these factors, there is a vicious cycle in which diarrhea worsens malnutrition by reducing the gut’s capacity to absorb nutrients. Persistent diarrhea is defined by WHO, diarrhea (≥ 3 loose/watery stools daily) lasting 14 days or longer posing higher risk of malnutrition than acute diarrhea. This review explores the interconnected nature of these conditions and their cumulative impact on child health and development. A comprehensive literature review was conducted using databases such as Google Scholar, PubMed, Web of Science and Scopus, focusing on studies examining the pathophysiology, clinical manifestations, and management strategies in malnourished children. This review explores current evidences on etiology (E. coli, Cryptosporidium, sequential infections), pathophysiology (malabsorption, villus atrophy, enteric inflammation), dietary interventions (zinc, vitamin A, glucose-polymer ORS) and microbiome-based (probiotics, dysbiosis, correction) strategies of persistent diarrhea. Findings show that persistent diarrhea causes mucosal damage and nutrient malabsorption, while secondary lactose intolerance leads to osmotic diarrhea and further caloric loss. Gut dysbiosis, marked by the depletion of beneficial bacteria and overgrowth of pathogens, impairs digestion, disrupts immune function, and sustains chronic inflammation. Together, these conditions create a vicious cycle that perpetuates malnutrition and stunting. Recommended interventions include oral rehydration therapy, lactose-restricted diets, micronutrient supplementation (particularly zinc and vitamin A), and microbiota-based therapies such as probiotics and prebiotics. The review concludes that integrated approaches—combining nutritional support, microbiome restoration, and improved hygiene—are essential for breaking the cycle of malnutrition and gastrointestinal disease. Addressing these issues through targeted public health policies and personalized interventions can significantly improve outcomes for vulnerable pediatric populations.