Gastrointestinal pH profile in subjects with irritable bowel syndrome

AIM: To investigate the small bowel pH profile and small intestine transit time (SITT) in healthy controls and patients with irritable bowel syndrome (IBS). METHODS: Nine IBS patients (3 males, mean age 35 yr) and 10 healthy subjects (6 males, mean age 33 yr) were studied. Intestinal pH profile and SITT were assessed by a wireless motility pH and pressure capsule (Smart Pill). Mean pH values were measured in the small intestine (SI) and compared both within and between groups. Data presented as mean or median, ANOVA, P <0.05 for significance. RESULTS: We found the pH for the first (Q1), second (Q2), third (Q3), and fourth quartile (Q4) of the SI in healthy versus IBS patients was 5.608 ± 0.491 vs. 5.667 ± 0.297, 6.200 ± 0.328 vs. 6.168 ± 0.288, 6.679 ± 0.316 vs. 6.741 ± 0.322, and 6.884 ± 0.200 vs. 6.899 ± 0.303, respectively. We found no significant group difference in pH per quartile (P=0.7979). The proximal SI was significantly more acidic, compared to distal segments, in both healthy subjects and IBS patients (P<0.0001). We found no significant difference in the measured SITT between IBS and control groups with a mean SITT of 218.56 ± 59.60 min and 199.20 ± 82.31 min, respectively (P=0.55). CONCLUSION: This study shows the presence of a gradient of pH along the SI, in both IBS and healthy subjects, the distal being less acidic. These finding may be of importance in small bowel homeostasis.