GOALS This study was undertaken to evaluate the effects of probiotics on adult patients with irritable bowel syndrome (IBS) through clinical parameters and H nuclear magnetic resonance (NMR)-based metabonomics.

BACKGROUND As systematic effect of probiotics on inflammatory bowel disease through metabonomics approach has been extensively studied to date, metabonomic characterization of the probiotics effect on IBS is also needed for better understanding the effect with respect to host metabolic mechanism.

STUDY Seventy-four IBS patients meeting Rome criteria were randomized to receive probiotics and placebo through a parallel-group, double-blind, randomized, placebo-controlled clinical study. Probiotic fermented milk and placebo were administered 3 times daily for 8 weeks. Improvements of IBS were assessed according to Rome III questionnaires and H NMR metabolic profiling of serum and fecal samples from all participants was used to characterize a significant change in serum and fecal metabolome before and after probiotics.

RESULTS Fecal counts of the Lactobacilli, but not Bifidobacteria species, which included in the probiotic milk, were increased significantly in feces of IBS patients receiving treatment (P=0.014). NMR data set coupled with multivariate statistical analysis identified intrinsically elevated serum levels of glucose (P=0.0265) and tyrosine (P=0.0016) in IBS patients. These levels normalized to those of healthy individuals in the probiotic administration group, but not the placebo group.

CONCLUSIONS This metabonomic study suggests that in a subset of IBS patients there exists a potential dysregulation in energy homeostasis (serum glucose) and liver function (serum tyrosine) that may be improved through probiotics supplementation. Moreover, global metabolic profiling highlights the potential of metabonomic approach for assessing bowel diseases or symptoms with respect to host metabolic perturbation.