A research done in mice showing that probiotics could lower symptoms of depression and anxiety was made recently. However, it was reported that researchers from the McMaster University in Canada discovered that a different probiotic has the same effect on humans as well.

According to VOA News, the research involved 44 patients who were diagnosed with irritable bowel syndrome and mild to moderate anxiety or depression. Afterward, half of the patients were made to drink a probiotic called Bifidobacterium longum, which is also considered as a beneficial gut bacterium. Meanwhile, the other half of the participants were made to take a placebo.

"This study shows that consumption of a specific probiotic can improve both gut symptoms and psychological issues in IBS," said study lead author and Associate Professor at McMaster University in Canada, Premysl Bercik. Bercik also mentioned that the probiotic bacterium study opens avenues for treatments for both people with functional bowel disorders but as well as those with primary psychiatric diseases.

After being followed in 10 weeks, the patients were then analyzed using high-tech brain imaging in order to assess their brain’s response to happy and sad images. 14 of 22 or 64 percent of those patients who had taken the probiotic bacterium was then identified to have lower depression scores compared to the remaining seven of 22, or 32 percent who didn’t take it.

Bercik then noted that the results from those who had taken the probiotic bacterium were surprising. Aside from having the patient’s gut symptoms improved, their depression scores were lower compared to before. The study was published in the journal Gastroenterology.

Another study which supports probiotic and depression was reported by KQED Science. It was then told that 12 women participants were given yogurts containing Bifidobacteria and Lactobacillus. After taking the yogurt for 4 weeks, the participants were assessed using functional magnetic resonance imaging, or fMRI.

Dr. Kirsten Tillisch, the study’s lead researcher and a gastroenterologist at UCLA then explained that people experiencing anxiety tend to show increased responses to the images. Yet, the participants who took the probiotics showed less brain activity compared to those who took a placebo instead.