FIGURE 1.

Summary of the plausible links between CF, the gut microbiota, and child undernutrition. (A) Inadequate CF is associated with child undernutrition. These associations were mostly examined in LMICs. CF interventions often have limited effects on child growth, hinting at the complexity of the relation between CF and undernutrition. (B) Significant changes in the gut microbiota occur during the CF period. The introduction of new food components and the age of introduction and composition of the complementary food influence the gut microbiota. However, evidence in this area originates solely from HICs. (C) Gut microbiota disruptions are associated with, and causally linked to, child undernutrition. A bidirectional relation is plausible where a disrupted gut microbiota can cause undernutrition and vice versa. (D) Interventions for undernutrition targeting the gut microbiota during the CF period are promising. More research is needed to further our knowledge of the interplay between CF, the gut microbiota, and undernutrition as this can help better inform the design of interventions with long-lasting benefits to combat child undernutrition and promote health and well-being. CF, complementary feeding; HIC, high-income country; LMIC, low- and middle-income country.