ABSTRACT
Oligosaccharides have been dietary staples since antiquity but have received much less attention than other carbohydrates such as simple sugars or dietary fiber. Oligosaccharides are carbohydrates with a low degree of polymerization and consequently low molecular weight. Published data concerning the resistance of other oligosaccharides to digestion in the upper gastrointestinal tract are rare. For the galactooligosaccharides, the only in vitro data available concern pure batch cultures. With the inulin-type fructans and xylooligosaccharides, the selective stimulation of fecal bifidobacteria has been demonstrated in rats fed a diet supplemented with 5% resistant oligosaccharides. The colonic fermentation of resistant oligosaccharides produces short-chain carboxylic acids and lactate plus gases. Possibly related to this increase in the pool of short-chain carboxylic acids is the effect of some resistant oligosaccharides on the intestinal tissue leading to hyperplasia of the mucosa and increased wall thickness in both the small intestine and the cecum.
