Published online Dec 28, 2016. doi: 10.3748/wjg.v22.i48.10631
Peer-review started: April 14, 2016
First decision: June 20, 2016
Revised: July 13, 2016
Accepted: July 31, 2016
Article in press: August 1, 2016
Published online: December 28, 2016
Processing time: 256 Days and 22.1 Hours
To determine the effects of Lactobacillus acidophilus NCFM on irritable bowel syndrome (IBS) symptoms and quality of life (QoL).
In this randomized triple-blind trial, adult IBS volunteers who were recruited according to Rome III criteria received 109 or 1010 colony-forming units of NCFM or placebo daily for 12 wk. IBS Symptom Severity Score (IBS-SSS), which constituted the primary outcome, and secondary outcomes, including individual IBS symptoms, IBS-related QoL questionnaire, anxiety and depression, defecation frequency, and stool consistency, were assessed at baseline at the end of the 8-wk run-in period, after 4 and 12 wk of intervention, and after a 4-wk washout.
A total of 340 of 391 randomized volunteers completed the trial. IBS-SSS improved over 12 wk of treatment in all treatment groups, decreasing by a mean ± SD of 44.0 ± 80.2, 50.8 ± 82.4, and 48.3 ± 72.2 in the placebo, active low-dose, and active high-dose groups, respectively. Similarly, secondary outcomes did not differ between treatment groups. However, in a post hoc analysis of volunteers with moderate to severe abdominal pain at baseline (VAS > 35/100), the treatment significantly reduced the sensation of abdominal pain. Pain scores fell by 20.8 ± 22.8, 29.4 ± 17.9, and 31.2 ± 21.9 in the placebo, active low-dose, and active high-dose groups, respectively (P value for placebo vs combined active doses = 0.0460).
NCFM alleviates moderate to severe abdominal pain, consistent with earlier observations of this strain mitigating visceral pain through increased analgesic receptor expression.
Core tip: Symptoms of irritable bowel syndrome (IBS) might benefit from probiotic interventions, although mechanistic insights into probiotic function are seldom available. Lactobacillus acidophilus NCFM induces human colonic mucosal opioid receptor expression - the putative mechanism by which visceral pain is alleviated. In this study, 391 volunteers with IBS were treated with 109 or 1010 colony-forming units of NCFM or placebo and evaluated using symptom questionnaires. NCFM was not superior to placebo in improving the composite IBS symptom score, whereas abdominal pain - as an individual symptom - declined in IBS volunteers with moderate to severe pain at baseline.