Your body contains a truly massive amount of bacteria – over ten times the amount of your own cells! So it’s only natural that these passengers in our bodies play a major role in everything from our digestion to our immune systems to even our mental health.
The complexity of this relationship is represented in new research, which reveals that certain probiotic bacteria may actually improve memory and relieve anxiety. So make sure your diet includes plenty of probiotic-rich foods.
The research, which comes out of the University College of Cork, Ireland, noted that healthy men who were given doses of a specific probiotic bacteria responded differently to stressful situations and memory tests than men who were not.
Presenting The Preliminary Findings
The research is still in the preliminary phase and has yet to be published, but researchers presented it last week at the Society for Neuroscience meeting in Chicago (1). “Our understanding is quite limited in this area,” one researcher admitted, adding that “how the neurotransmitters in the gut interact with neurotransmitters in the brain requires more work. But these results do show that even in healthy volunteers, you can change nervous system activity by manipulating what is happening in the gut.”
The researchers say that they wanted to test the effects of probiotics on anxiety and memory in humans, building on previous studies which had been done in animal models (2).
Testing For Stress And Memory
Subjects in the study were tested using the Spielberger State-Trait Anxiety Inventory, to measure their anxiety levels, and given a number of tests involving the memorization of patterns. Probiotic use, the researchers found, seemed to correlate with better performance on these tests, and lower levels of anxiety.
“What is interesting about the memory test is that performance is associated with a brain region called the hippocampus, which is also influenced by stress,” the researchers said. “The HPA axis, which controls cortisol levels, interacts with the hippocampus, so the results seem to tie together.”
Due to its preliminary nature and small size, there are several limitations to this recent study, however. For instance, at the moment, researchers have no way of proving that the probiotic supplements taken by participants even made it to the intestinal tract – although the stool sample analysis should be able to shed some light on that question soon. Additionally, the study did not include women, in part because the researchers said their periods could affect cortisol output, complicating the study results.
However, the idea that probiotics have a marked impact on our mental state is hardly a new one. One 2014 review stated that “the emerging concept of a gut microbiota-brain axis suggests that the modulation of the gut microbiota may provide a novel therapeutic target for the treatment and/or prevention of mood and anxiety disorders.”(3) This would certainly seem to be in line with anecdotal evidence from those who manage their mental health through diet and exercise rather than pharmaceutical medications.