Computational modeling of solid food digestion inside the stomach

The stomach plays a vital role in the physical and chemical breakdown of ingested meals. Solid components of the meals are processed differently from liquids because only particles smaller than 2 mm are allowed to pass through to the intestines. Solid particles settle at the bottom of the stomach upon arrival and peristaltic contractions subject them to vigorous fluid motion leading to the grinding of the larger particles into smaller sizes, a phenomenon known as trituration. While previous studies have extensively modeled liquid meals, limited attention has been given to the physical breakdown of solids. Here we present a model that incorporates the trituration phenomenon and the subsequent emptying of solid meals into the duodenum. Imaging data is used to specify the wall motion and the properties of ingested food are derived from experimental studies on chewing. Lagrangian point-particle method is used to model the multiphase flow and a particle fracturing model is also included. We investigate the impact of food and motility parameters on particle trajectories and sizes. The model yields valuable insights into the gastric digestion of solid meals and the influence of wall motion in this process.