Does our bacterial flora influence our behavior and our mood?
My little bacteria
In a previous issue of HTS’Mag, you may have read the article “You are host to 100,000 billion bacteria!” concerning microbiota (or bacterial flora). Our microbiota is all the microorganisms that we “host” in and on our bodies. And they are good for us, especially for the proper functioning of the digestive system.
But what about our behavior, our mood, our stress levels? Surprising studies are beginning to suggest that there may be a link…
The Second Brain
Our intestines harbour a vast majority of our microbiota. Our microscopic guests are not content to assist us with “mechanical” functions such as digestion: they also communicate with our brain, which gives our stomach the lovely nickname of “second brain”.
So, a brain in the stomach… That might sound somewhat perplexing! Yet, as it turns out: communication in the microbiota-stomach-brain axis is done through substances produced by some of our bacteria acting on nerve endings through “translator” cells.
Psychological State & Microbiota
Our microbiota changes over time, and also changes according to our eating habits, our health, etc. And it seems to affect our psychological state by playing on many factors: anxiety, mood, stress, control of emotions — our behaviors.
Many studies have been conducted on mice. The results are promising. For example, stress or “adventurous” behaviors are not the same in a “normal” individual as they are in individuals born and confined in a sterile environment, where naturally occurring bacterial flora are not able to colonize.
Mice kept in a sterile environment, and then inoculated with the bacterial flora of a “normal” mouse, showed behavior changes after inoculation.
“The doctor in spite of himself”
Our microbiota may also have an influence on the development and progression of diseases such as obesity, diabetes, autism, Parkinson’s disease and multiple sclerosis. Similarly, it is likely that the mechanisms of hunger and satiety, as well as changes in fatty tissue, are related to the composition of bacterial flora.
This suggests that an imbalance of the microbiota is related to certain disorders. Medical studies are underway on microbiota as possible treatments for mood regulation, anxiety as well as a number of diseases. It is of course too early to tell, but probiotic treatments may well eventually give life to real solutions.
Firmicutes, bacteroidetes and other Actinobacteria… Again, although they are invisible to the naked eye, the importance of microorganisms in the function of the human body is clear.