Subjective, but not documented, lactose intolerance accompanies irritable bowel syndrome

Abstract Introduction Lactose intolerance, due to lactase deficiency, may overlap with the symptoms of irritable bowel syndrome (IBS) or lead to an incorrect diagnosis of IBS. Identification of lactose intolerance and lactase deficiency enables targeted treatment to be implemented. The aim of the study was to search for a frequency of a lactose intolerance symptoms in patients with IBS, depending on the results of hydrogen breath test (HBT). Materials and Methods The study involved 56 patients with IBS and 23 healthy people. Both, IBS patients and healthy controls, were asked to complete a survey about IBS symptoms and tolerance of lactose-containing products. A HBT was performed on all subjects. Results Lactase deficiency was diagnosed in 60.7% of patients with IBS and 43.5% of control group. The differences between the study groups were not statistically significant. No statistically significant differences were observed between the incidence of lactase deficiency depending on the type of IBS. In the group of patients with IBS and normal HBT results, as well as in patients with IBS and lactase deficiency, there were no statistically significant differences in the frequency of lactose intolerance symptoms. However, among people with normal HBT results, patients with IBS reported symptoms of intolerance after consuming lactose-containing foods significantly more often compared to the control group (p<0.05). Conclusions Frequency of lactase deficiency does not differ between IBS patients and healthy individuals. Patients with IBS are more likely to report symptoms of lactose intolerance, regardless of the HBT result, compared to healthy individuals.