9The enteric microbiota in the pathogenesis and management of constipation

For centuries, fiber has been recommended on an empirical basis for the management of constipation; it has only been in recent decades that the mechanisms whereby fiber and related products may influence colonic function have begun to be elucidated. The interaction between fiber and the microbiota of the human colon appears to play a major role in generating the beneficial effects of fiber. The microbiota is also the target for the other therapeutic interventions discussed in this chapter: prebiotics and probiotics. While a scientific basis for a role for these approaches in the management of constipation continues to develop, evidence from high-quality clinical trials to support their use in daily practice continues to lag far behind. While benefits for fiber and, perhaps, for certain prebiotic and probiotic preparations in constipation appear to be extant there is a real need for large well-conducted clinical trials in this important area of human medicine.