The probiotic Bifidobacterium longum improved depression and quality of life, but not anxiety, among individuals with irritable bowel syndrome.
“This study shows that consumption of a specific probiotic can improve both gut symptoms and psychological issues in [irritable bowel syndrome],” Premysl Bercik, MD, of McMaster University, Hamilton, Ontario, said in a press release. “This opens new avenues not only for the treatment of patients with functional bowel disorders but also for patients with primary psychiatric diseases.”
To determine effects of Bifidobacterium longum on anxiety and depression in individuals with irritable bowel syndrome (IBS), researchers conducted a randomized, double-blind, placebo-controlled study of 44 adults with IBS and diarrhea or a mixed-stool pattern and mild-to-moderate anxiety or depression. Study participants were randomly assigned to receive the probiotic (n =22) or placebo (n = 22) daily for 6 weeks. Anxiety, depression, IBS symptoms, quality of life and somatization were assessed at weeks 0, 6 and 10.
At week 6, 14 participants in the probiotic group exhibited reductions in depression scores of 2 points or more, compared with seven participants in the placebo group (P = .04).
did not significantly affect anxiety or IBS symptoms, according to researchers.
Participants who received the probiotic had increased quality of life, compared with placebo.
Functional MRI analysis indicated Bifidobacterium longum reduced responses to negative emotional stimuli in multiple areas in the brain, including the amygdala and frontolimbic regions, compared with placebo.
Fecal microbiota profiles, serum markers of inflammation and neurotrophins and neurotransmitter levels were comparable between treatment groups. However, participants who received the probiotic had lower levels of methylamines and aromatic amino acids metabolites in urine samples.
At week 10, depression scores were lower among participants who received Bifidobacterium longum, compared with placebo.
“The results of this pilot study are very promising but they have to be confirmed in a future, larger scale trial,” Maria Ines Pinto-Sanchez, MD, of McMaster University, said in the release. – by Amanda Oldt
Disclosure: Pinto-Sanchez reports no relevant financial disclosures. Please see the study for a full list of relevant financial disclosures.