ABSTRACT
The existence of an active bacterial population in the human large bowel has been known for a relatively long time, but only has the importance of this colonization to the maintenance of colonic health become appreciated. For the fermentation to proceed, the bacteria require a source of nitrogen, which can be provided through the breakdown of dietary and endogenous protein or urea. The evidence suggesting an etiological role for diet and supporting dietary change to improve the management and prevention of each of these conditions is variable. The evolution of fiber chemistry has included the progressive development of more advanced technology to determine dietary fiber, including methodologies to measure nonstarch polysaccharides. Dietary interventions in humans are relatively short term, while only a few of the studies in animals have been carried out under conditions that approximate the dietary intakes of the population at large.
