We've all been there. A question arises and you know the answer and yet, even though it might be on the tip of your tongue, you just can't seem to grasp it. It's a frustrating experience revealing one of the most important aspects of life: the ability to remember. Unveiling how memories are formed, retained and recollected has been one of research's greatest challenges. Although the mechanisms are becoming known, when it comes to manipulating the brain to improve memory, the answers have been far more elusive.
Germs however, may have already solved the riddle.
The impact of gut bacteria on the brain and mind has been known for years and a significant amount of research has focused on the gut-brain axis. The results have shown that the composition of the microbiota in the gut drives different brain functions, including mood, anxiety, and even depression. But when it comes to improving memory, probiotics have been given little thought.
In 2011, a group led by a team from the Hospital for Sick Children revealed that there might be a reason to reconsider. Their research didn't focus on the improvement of memory by bacteria but the opposite. The authors infected mice with a known bacterial pathogen and then looked for any changes in memory function. Sure enough, the mice had problems remembering. Worse, the condition lasted long after the infection was cleared. There was, however, one way to prevent this outcome. By administering probiotics on a daily basis, the effects of infection were prevented.
Adding to the evidence in support of probiotics and memory was a study published last year from a group in Iran supporting probiotics for better memory and overall learning process. In this case, they gave probiotics to rats that are prone to diabetes and then tested their spatial memory as well as their ability to learn a maze. As expected, those fed probiotics were better at both tasks.
A third and even more enlightening article was published earlier this year. The team from the University of Alberta fed mice with the equivalent of a Western diet and noticed several changes in the animals. They gained weight, they were more anxious and they appeared to have memory problems. By providing them probiotics, however, their mental state and memory returned to normal. In essence, the authors showed that at least in mice, a Western diet is bad for memory yet this can be rescued by the administration of probiotics.
In all these studies, the function of memory restoration and improvement was linked to stress, a known problem for brain function and memory. Whether infection, diabetes, or simply a Western diet, there was a systemic increase in stress and that in turn hurts our ability to remember. Yet, when probiotics were given, the body calmed down and allowed the brain and memory to function normally.
With these studies hinting at the nature of memory problems and potential ways to resolve them with probiotics, it was not surprising that this week, two authors at the Post Graduate Institute of Medical Education and Research in Changigarh, India offered the first suggestion that bacteria, specifically probiotics, may offer a means to enhance memory. The letter not only makes the case for the use of probiotics to help memory but also the development of personalized probiotics. By understanding how a person is being negatively affected by their surroundings, a select group of bacteria can be provided to help calm the stress and retain a healthier and happier self.
Of course, the era of bacterial prescriptions is still years away. In the human context, the effect of probiotics on memory is barely on the radar. The only study so far to examine memory revealed less than encouraging results although the authors suggested that testing was less than thorough. Today, only one clinical trial is looking at the impact of bacteria on the ability to remember although it too only comprises a small part of a larger investigation.
As the evidence continues to grow in support of probiotics for memory, more clinical trials -- and presumably tests in citizen science -- will be performed to develop a clearer picture. Until then, there is ample reason to explore probiotics and their benefits to improve the health of not only the gut, but also the brain and mind.