Figure 1.

Dietary fiber and other fermentable substrates are fermented by the gut microbiota leading to the production of SCFAs. These metabolites interact with GPCRs or MCTs and SMTCs transporters leading to the regulation of gene transcription and energy productions in IECs. SCFAs can also passively cross the intestinal mucosa and regulate intestinal immunity and pass into the circulation to modulate metabolic and immune functions in different body organs. SCFAs; short-chain fatty acids, GPRs; G protein-coupled receptors, MCTs; Monocarboxylate transporters, SMTCs; Sodium-coupled monocarboxylate transporter; DC, dendritic cell, Treg; T regulatory cell, Mϕ; Macrophage.