Physical properties of dietary fiber that influence physiological function: a model for polymers along the gastrointestinal tract.

The quantitative measurement of dietary fiber does not recognize its diverse actions on nutrient absorption, sterol metabolism, fermentation in the colon, and stool weight. These differences in action are more likely due to differences in physical characteristics along the gastrointestinal tract. This paper explores such physical characteristics and attempts to classify dietary fiber in a more physical manner. This approach recognizes the diverse and variant action of each dietary fiber, which may be modified as a result of processing and cooking without changing in any way the quantitative measurement of dietary fiber. The general principles developed in this paper could also be applied to other polymeric materials passing along the gastrointestinal tract.