The Chemo-Fluid Dynamics of Digestion in the Stomach: Insights from Computational Modeling*

The stomach acts simultaneously as a mixer, grinder, siever, and bioprocessor of food, and the chemo-fluid dynamics of the digestion process in the stomach are central to our health. The peristaltic motion of the stomach walls combines with the secretion of enzymes to break down food (proteins, lipids, and carbohydrates) into lower molecular weight components that are ejected into the duodenum for digestion. Computational modeling of this phenomenon can fill the gaps left behind by the experimental approaches. In this study, the digestion of a protein shake in an MR derived model of the human stomach is simulated using a newly developed in-silico model “StomachSim”. In the current model, pepsin, the enzyme that hydrolyses protein, is secreted from the proximal region of the stomach walls and allowed to react with the contents of the stomach. The mixing of the contents, the extent of hydrolysis, and the emptying from the stomach are quantified for a healthy stomach, as well as for a stomach affected by gastroparesis. The findings demonstrate the potential of computational approaches to provide  data and insights that are complementary to in-vivo or in-vitro methods.