Gut-brain axis in the early postnatal years of life: A developmental perspective

In the first two to three years of life, the development of the gastrointestinal (GI) tract and the brain in humans occurs in parallel. Emerging evidence suggests that alterations in the development of GI tract during this critical period can influence brain development and vice-versa. It is increasingly recognized that communication between the GI tract and brain is mainly driven by neural, endocrine, immune, and metabolic mediators, collectively called the gut-brain axis (GBA). However, it is unclear whether changes during the early-postnatal period in the GBA also occur in response to the parallel development of the GI tract and brain. This review summarizes the communication between the GI tract and brain in response to their development in the early postnatal period.