Patients with Irritable Bowel Syndrome (IBS) are often diagnosed with small intestinal bacterial overgrowth but seldom tested for carbohydrate malabsorption. To look at this issue of carbohydrate malabsorption a research group in Germany studied 2,390 IBS patients. Each patient received a hydrogen breath test for fructose malabsorption and lactose intolerance. The result was that 35% of the patient tested positive for lactose intolerance and 64% for fructose malabsorption. This lead the researchers to conclude that lactose and fructose intolerances are a frequent but underestimated condition in patients with IBS symptoms.
Ref: J Neurogastroenterol Motil Vol 20, No. 2 April 2014