The role of probiotics for gastrointestinal conditions is well known, however a new study shows a specific strain of probiotics may also relieve symptoms of depression, according to research from McMaster University and published in the journal Gastroenterology (May 2, 2017). Researchers say this study offers further evidence of how probiotics may alter brain activity.
The probiotic Bifidobacterium longum NCC3001 showed that twice as many adults with irritable bowel syndrome (IBS) reported improvements from co-existing depression when they took as compared to placebo.
The researchers of the Farncombe Family Digestive Health Research Institute say this study 
provides further evidence that the microbiota environment in the intestines are in direct communication with the brain, said senior author Dr. Premysl Bercik, an associate professor of medicine at McMaster and a gastroenterologist for Hamilton Health Sciences. “This study shows that consumption of a specific probiotic can improve both gut symptoms and psychological issues in IBS. This opens new avenues not only for the treatment of patients with functional bowel disorders but also for patients with primary psychiatric diseases,” he said.
The pilot study involved 44 adults with IBS and mild to moderate anxiety or depression. They were followed for 10 weeks, as half took a daily dose of the probiotic Bifidobacterium longum NCC3001, while the others had a placebo.
- At six weeks, 14 of 22, or 64%, of the patients taking the probiotic had decreased depression scores, compared to seven of 22 (or 32%) of patients given placebo.
- Functional Magnetic Resonance Imaging (fMRI) showed that the improvement in depression scores was associated with changes in multiple brain areas involved in mood control.
“This is the result of a decade long journey – from identifying the probiotic, testing it in preclinical models and investigating the pathways through which the signals from the gut reach the brain,” said Bercik. “The results of this pilot study are very promising but they have to be confirmed in a future, larger scale trial,” said Dr. Maria Pinto Sanchez, the first author and a McMaster clinical research fellow.
