Digestion modeling in the small intestine: Impact of dietary fiber

In this work, the modeling of the digestion in the small intestine is developed by investigating specifically the effects of dietary fiber. As our previous model, this new version takes into account the three main phenomena of digestion: transit of the bolus, degradation of feedstuffs and absorption through the intestinal wall. However the two main physiochemical characteristics of dietary fiber, namely viscosity and water holding capacity, lead us to substantially modify our initial model by emphasizing the role of water and its intricated dynamics with dry matter in the bolus. Various numerical simulations given by this new model are qualitatively in agreement with the positive effect of insoluble dietary fiber on the velocity of bolus and on its degradation all along the small intestine. These simulations reproduce the negative effect of soluble dietary fiber on digestion as it has been experimentally observed. Although, this model is generic and contains a large number of parameters but, to the best of our knowledge, it is among the first qualitative dynamical models of fiber influence on intestinal digestion.