SCFAs such as butyrate are derived from fermentation of dietary fibers by SCFA-producing microbiota such as Clostridium. Butyrate provides the majority of the energy for enterocytes and promotes gene transcription and cell proliferation. It stimulates innate lymphoid cells (ILC3s) to produce interleukin-2 (IL-22), which enhances intestinal stem cell proliferation and differentiation. Butyrate also stimulates regulatory T-cell generation and activation, as well as effector T-cell functions.