The digestive system processes not only food but information — it houses roughly 70 percent of the immune system and a neural network so complex it is sometimes called the second brain, communicating upward via the vagus nerve. The microbiome — the trillions of microorganisms living in the gut — influences mood, immunity, metabolism, and cognitive function, and is shaped by diet, medications, stress, and environment. Tending to digestion is, in ways that continue to be mapped, tending to the whole person.
Each step builds on the last.