  The emerging field of Molecular Communication (MC) aims to characterize
biological-based signaling environment through information that are encoded
into molecules. Since the birth of this field, a number of different
applications and biological systems have been characterized using MC theory.
This study proposes a new application and direction for MC, focusing on the
digestive system, where we characterize and model the starch and glucose
propagation along the small intestine. Based on the advection-diffusion and
reaction mechanisms, we define a channel capacity for the small intestine
digestive tract that is dependent on the starch to glucose conversion, velocity
flow within the tract, viscosity of the digest product, and length of the tract
and position of the receivers for glucose absorption. The numerical results
from the derived channel capacity model shows that the SI digestive capacity
depends both on physiological factors of the digestive system and type of
consumed food, where the digestive capacity is greater for shorter gastric
emptying time, low viscosity of the digest product and efficient enzyme
activity. We believe that our digital MC model of the digestive tract and lead
to personalized diet for each individual, which can potentially avoid a number
of different diseases (e.g., celiac disease).
