In our intestines an army of microbes works tirelessly, every day. Not only to help us digest, but also to directly influence our mood. Our little allies have become protagonists of a scientific revolution that is rewriting the rules of psychology and neurology. But how can a microbe, so small and invisible, have such a large impact on our mind? Let's get ready for a little journey to discover Psychobiotics.
The connection between the gut and the brain: an ancient history
The connection between the gut and the brain is not a recent discovery. The legendary Hippocrates, already 2.500 years ago, believed that all diseases, including brain diseases, originated in the intestine. And of course, Hippocrates didn't know what a microbe was. This knowledge would have to wait until the late 1600s, when Antoine van Leeuwenhoek, thanks to his small portable microscope, began to reveal the world of microbes.
In the late 1800s, Russian zoologist Elie Metchnikoff made a surprising discovery. He noticed that long-lived Bulgarians consumed large quantities of yogurt, which was rich in bacteria. Metchnikoff postulated that it was precisely this consumption of yogurt that ensured them such a long life. The idea that bacteria like the Lactobacillus could contribute to health, laid the foundation for the concept of probiotics. And now?
The birth of psychobiotics
As the 21st century arrived, research into the gut-brain connection began to gain traction. In 2004, Nobuyuki Sudo ha published an article revolutionary on germ-free mice, i.e. grown in a sterile environment. These mice showed an abnormal response to stress. Somehow, the presence or absence of bacteria affected their behavior.
Even more surprisingly, when Sudo reintroduced the bacteria into the mice's intestines, their behavior returned to normal. This discovery triggered a real "fever" in research on the gut-brain connection. It was the embryo of a science that would only be born ten years ago.
Psychobiotics: the new allies of our mood
In subsequent years, John Cryan e Ted Dinan, two researchers from University College Cork, have further delved into the mystery of the gut-brain connection.
In 2013, they coined the term “psychobiotics” to refer to the study of microbes that can improve mood. Not simple bacteria, but real allies that work in symbiosis with us.
How do psychobiotics work?
Psychobiotics communicate with the brain through at least three chemical pathways: i neurotransmitters, The hormones and immune factors. It is surprising to discover that microbes produce neurotransmitters identical to those present in our brain, such as dopamine, serotonin and GABA.
These neurotransmitters are picked up by nerve cells surrounding the intestine and sent to the brain via the vagus nerve. If this nerve is severed, the effects of psychobiotics disappear.
The last decade has consolidated the importance of psychobiotics for our mental health. Specific psychobiotic bacteria have been identified, such as Lactobacillus rhamnosus and Lactobacillus reuteri, which reduce anxiety by influencing GABA levels. Others, like the Bifidobacterium longum 1714, reduce cortisol levels improving mood and cognition. These little allies of our intestines have a huge influence on our behavior, leading us to ask ourselves: “Who is really in charge?”.
Where we are today and where we are going: the future of psychobiotics
The next decade promises further discoveries in the field of psychobiotics. Research is already showing that some forms of depression and anxiety can be alleviated or cured with psychobiotic treatments. Perhaps, in the future, a bowel examination could become common practice in psychiatric evaluation.
Stay tuned, and in the meantime continue to nourish your small intestinal allies: healthy intestine in healthy body.
