The Gut–Lung Axis in Allergic Asthma: A Narrative Review of Microbial Dysbiosis, Immune Regulation, and Nutritional Modulation

Allergic asthma is a prevalent chronic inflammatory disease of the airways whose pathogenesis has traditionally been attributed to localized immune dysfunction within the lung. However, accumulating evidence from microbiome research supports a broader system-level perspective in which cross-organ interactions contribute to disease susceptibility and progression. In particular, the gut–lung axis has emerged as a key regulatory pathway linking intestinal microbial ecology, immune development, and