Abstract
The human large bowel contains a large variety of bacterial genera, species and strains. Nondigestible food ingredients that escape digestion in the small intestine are thought to be important substrates for some colonic bacteria. The human intestinal bacterial ecosystem has been adapted to nondigestible but fermentable carbohydrates. Ingestion of several nondigestible but fermentable dietary carbohydrates results in a different spectrum of fermented products including the production of a high concentration of short chain organic acids. The most predominant anaerobic bacteria in the colon are able to ferment nondigestible carbohydrates. Moreover, the spectrum of fermented products differs, depending on the amount of carbohydrates. The significance of carbohydrate availability with respect to aromatic amino acid metabolism was shown in fecal batch culture fermentation. Fecal batch culture with arabinogalactan showed a decrease of indole with the cultivation time in two of three cases. Some intestinal bacteria seemed to dissimilate indole. It is the reason why no significant correlation was found between indole and fecal moisture in our previous study.It might be possible to estimate the bowel condition by examining fecal bacterial compositions and other fecal factors such as moisture, concentrations of organic acids and putrefactive products in special cases.
