Tolerance to low-digestible carbohydrates: symptomatology and methods

Low-digestible carbohydrates (LDCs) are incompletely or not absorbed in the small bowel and fermented in the colon. They are usually well tolerated but may also have some dose-related undesirable effects due to their natural osmotic potential and/or excessive fermentation: borborygmi, excessive flatus, bloating, abdominal cramps and eventually diarrhoea. There is an important intersubject variability in the tolerance to LDCs because of differences in absorption capacity, motility pattern, colonic response and intestinal sensitivity. There is also a great intrasubject variability, depending on the type of LDC, dosage and type of consumption. Absorption of LDC in the small intestine can be assessed using hydrogen breath test or intubation techniques or analysis of ileostomy effluents. Double-blind, placebo-controlled studies are required to assess the subjective symptoms of intolerance, and the experimental conditions may influence the results.