IFNG and asthma: SCFAs, particularly acetate, propionate, and butyrate, are produced by gut bacteria through fermentation of dietary fibers and bind to G-protein-coupled receptors (GPR41, GPR43, GPR109A), promoting the differentiation of regulatory T cells and inhibiting eosinophilic recruitment, suppressing Th2-driven allergic inflammation in asthma.182,183 SCFAs enhance Treg differentiation by inhibiting histone deacetylase,183–186 leading to epigenetic changes that upregulate immune-regulating genes, including those involved in the production of interferon-gamma (IFN-γ).