FRUCTANS OF CHICORY - INTESTINAL TRANSPORT AND FERMENTATION OF DIFFERENT CHAIN LENGTHS AND RELATION TO FRUCTOSE AND SORBITOL MALABSORPTION

Fructans (fructooligosaccharide a and inulin) are of increasing intere st to clinical nutritionists as functional food additives. The chemica lly closely related food carbohydrates fructose and sorbitol are impli cated in functional bowel disease. Intestinal handling of these carboh ydrates is incompletely understood. Intestinal absorption, transit, an d fermentation (breath hydrogen and methane, venous acetate, blood glu cose, and urine fructans) after ingestion of 10-30 g short- and long-c hain fructans from chicory were studied by single-blind, crossover ran domization in 10 healthy adults. Responses were compared with response s after ingestion of lactulose, fructose, and sorbitol. Breath hydroge n and venous acetate production increased in proportion to increasing fructan dose and were similar to responses to lactulose. The transit t imes of long-chain fructans were longer than those of short-chain fruc tans (75 compared with 30 min, P<0.001). Semiquantitative estimates of unabsorbed carbohydrate were not significantly different with either short-chain fructans or lactulose as nonabsorbable standards. Venous a cetate curves were less precise estimates of the magnitude of carbohyd rate malabsorption than were breath-hydrogen curves (P<0.01). All subj ects showed malabsorption of 50 g fructose, resulting in significantly more symptoms than 20 g fructose (P<0.05). Ingestion of sorbitol with equimolar amounts of glucose did not reduce malabsorption or abdomina l distress. Abdominal symptoms after fructans increased with increasin g dose and decreasing chain length. The overall gastrointestinal effec ts of short-chain fructans seem similar to those of lactulose. Fructan s with different chain lengths may have different physiologic properti es and further studies of fructans in disease states are warranted.