The importance of gut bacteria might not be relevant to our physical health only. A new study suggests that the daily consumption of probiotic capsules leads to decreased stress and enhanced memory.
The new research has brought forth findings that add to those of previous studies: microorganisms might be relevant to mental health.
22 volunteers were made to take probiotic capsules containing over a billion Bifidobacterium longum 1714 everyday for a month; they were then fed with placebo for another month without them knowing.
It was later found that they felt less stressed than before the trial and during the second month. They also had lower levels of the stress hormone cortisol in their blood.
Furthermore, they did better for memory tests which entailed pairing objects together. Again, the improvement was noted after the first month, and not after the second one.
“When they were given these bacteria they were less anxious and their capacity to memorise material seemed to be enhanced,” says lead researcher Ted Dinan from the University College Cork in Ireland in statement to The Guardian. “The effect was large enough for them to perceive less stress.”
However, the sample size being small, the results are not considered to be conclusive. On the other hand, the findings seem to support previous studies performed by Dinan where probiotics appeared to boost the memories of mice, on top of having an antidepressant effect.
“This study is one of the few examples where someone has taken a probiotic from preclinical studies and put it into humans and found pretty much the same thing as in rodents,” he said.
Will the same effect be reproduced in humans? More studies need to be done to answer this question. Dinan is, however, positive that we will soon find that probiotics are actually beneficial to mental health.
“By their very nature, probiotics are safe bacteria, and if we can delineate those that have benefits for mental health, that would be a major advance for neuroscience and psychiatry,” says Dinan. “My hope is that within the next five years we’ll have a probiotic or two on the market that will be effective for treating mild forms of anxiety and depression.”