Does fecal calprotectin increase may be linked to lactose intolerance in patients with irritable bowel syndrome?

Background: Irritable bowel syndrome (IBS) is a multifactorial condition without any specific investigation. Fecal calprotectin (FC) may be elevated in IBS without any explanation. In addition, some patients with IBS have symptoms related to lactose intolerance. Our main aim was to investigate whether an increase in FC could be related to lactose intolerance in patients with IBS.

Methods: In this retrospective single-center study, all patients with IBS who have underwent a FC test and a lactose respiratory test within a period of less than 6 months were eligible. A FC greater than or equal to 50 μg/g was considered abnormal.

Results: Severnty-six patients (48 females), mean age 38±15 years were included. Symptoms were respectively: bloating in 57%, diarrhea in 76% and abdominal pain in 46% of cases. Among the 76 patients: 22 (29%) had FC≥50 μg/g and 9/22 (41%) had a positive lactose test. No significant relationship could be identified between the increase in FC and the lactose test positivity. The value of the FC was also not related to the subtype of IBS or the positivity of the glucose test.

Conclusions: In our study, the increase in FC was not significantly related to the presence of lactose intolerance. Nevertheless, our work, despite its originality, is limited by its retrospective nature and small number of patients. Future studies including larger numbers of patients may identify the causes of elevated FC in patients with IBS to individualize different subgroups of patients to best adapt therapeutic management.