A One Health Decalogue for Breastfeeding: Microbiota-Targeted Strategies for Infant Gastrointestinal and Neurodevelopmental Health

Background/Objectives: Breastfeeding represents a critical developmental window during which maternal biology, environmental exposures, and nutrition converge to influence infant gastrointestinal health and long-term developmental trajectories. From a One Health perspective, breastfeeding can be conceptualized not as a static nutritional act, but as a dynamic and modifiable biological system in which maternal factors shape early-life microbiota assembly and immune programming. This narrative review explores how microbiota-oriented strategies during breastfeeding may foster a favorable trajectory of infant health, potentially extending to transgenerational outcomes. Methods: This narrative review is structured around a ten-point decalogue addressing interconnected domains relevant to the maternal–milk–infant microbiota axis, including maternal diet, microbial diversity, environmental exposures, psychological stress and probiotic use. Current mechanistic and clinical evidence was examined to evaluate how these domains may modulate microbiota composition and function during breastfeeding. Attention was given to probiotic supplementation, including strain specificity, timing of administration, and clinical context, as well as to the broader implications of a One Health framework. Results: Available evidence suggests that maternal nutritional patterns, environmental and psychosocial exposures, and targeted microbiota-modulation strategies may influence the composition and functional properties of human milk and the developing infant microbiota. Probiotic use during breastfeeding appears to have strain-specific and context-dependent effects, with potential benefits in selected clinical scenarios. However, findings remain heterogeneous, and uncertainties persist regarding optimal strains, timing, and long-term outcomes. Conclusions: Breastfeeding can be understood as a dynamic biological interface shaped by maternal and environmental factors. Integrating microbiota-oriented strategies within a One Health framework may support infant gastrointestinal health and possibly contribute to longer-term developmental trajectories. Nevertheless, careful interpretation of the current evidence is warranted to avoid reductionist, supplement-centered approaches and to prevent maternal overmedicalization or blame.