Physics of gut motility impacts absorption and bacterial growth

Malfunctioning of the small intestine contractility and the ensuing bacterial population therein are linked to a plethora of diseases. We here study how the small intestine's variety of contractility patterns impacts nutrient uptake and bacterial population. Our analytical derivations in agreement with simulations identify flow velocity as the key control parameter of the nutrients uptake efficiency and bacterial growth, independently of the specifics of contractility patterns. Self-regulating flow velocity in response to the number of nutrients and bacteria in the gut allows achieving 100\% efficiency in nutrient uptake. Instead of the specifics of intestine contractility, our work points to the flow velocity and its variation in time within the intestine to prevent malfunctioning.