This prospective, randomised, double blind and placebo-controlled study investigated the short- and long-term effects of Lactobacillus reuteri ATCC 55730 on clinical symptoms of irritable bowel syndrome (IBS). 54 patients, with a mean age of 46 years, were randomised to take either a tablet with 10^8 CFU of Lactobacillus reuteri, twice daily, or a similar placebo tablet.
The participating subjects were of all IBS symptom types: constipation or diarrhoea dominant, or mixed types of symptoms, respectively. Both the probiotic and the placebo group subjects significantly improved in their symptoms during the study period of six months. There were no statistical differences between groups, although there was a tendency with time of decreased frequency of constipation and passing of gases in the Lactobacillus reuteri group (P=0.0714 and P=0.0971, respectively).
Conclusion: The strong placebo effect and the lack of uniformity in type of IBS in these patients may contribute to the results not reaching higher levels of statistical significance.
Comment: This study was originally designed to include twice the number of subjects, at two research sites. Since only one site fulfilled its assignment, the size of the evaluated population became too low to be able to detect any statistically significant differences between the study groups.”