There is mounting evidence that gut bacteria have a significant influence on mood and behaviour. This has many scientists referring to the gut microbiome (i.e. the microorganisms living in the gastrointestinal tract) as the “second brain”. New research is showing that gut bacteria may have a strong impact in how our brain develops, how we behave, react to stress, and control stress-related conditions, such as anxiety and depression.
So, a new frontier of neuroscience called the “Gut-Brain Axis” is emerging. This is an imaginary bidirectional line between the brain and the gut. Scientists have long recognized communication between the brain and the gut. Yet, they looked at it in the classical view of top-down control – where the brain controls gut function. Now, scientists are discovering the reverse is true too. That the gut microbiome can influence brain function.
"95% of the body’s supply of the mood-stabilizing chemical serotonin is made in the gut."
Aside from the many other jobs gut bacteria perform, they are also known to make many types of neurochemicals. The brain uses these neurochemicals to regulate basic physiological processes and mental processes, like learning, memory, and mood. In fact, 95% of the body’s supply of the mood-stabilizing chemical serotonin is made in the gastrointestinal (GI) tract. Fun fact to share at your next dinner party while noshing on hors d’oeuvres!
Research from studies in rodents has found that the gut microbiome can influence neural development, brain chemistry, and behaviours, including emotional behaviour, pain perception and stress responses. For example, studies have found that tweaking the balance between beneficial and harmful gut bacteria in mice can alter their brain chemistry and lead them to become either bolder or more anxious.
"To fully understand our behaviours and emotions, we need to look at the gut as much as the brain."
This research into how gut bacteria affects our mental well-being is still in its infancy. There haven’t been many studies done that directly link the human microbiota to mood or anxiety disorders (aside from this recent one led by UCLA). But, scientists are becoming increasingly convinced that to fully understand our behaviours and emotions, we need to look at the gut as much as the brain. I concur!
What the studies are finding is that in stressful situations, or in response to physiological or diet changes, the bacterial composition may itself change. This then creates an imbalance between good and bad gut bacteria. These types of changes can affect a person’s physical and mental well-being.
In the end, this all links back to how important nutrition and lifestyle are to our health. They have a direct role to play in the balance of good to bad microbes in our guts.
Definitely check out the article links below for a deeper look at the recent research findings with the gut-brain axis.
And while scientists are still figuring this all out, if you’d like to find more about what you can do now to select for the good gut bacteria through nutrition and probiotic supplementation, send me an email at firstname.lastname@example.org.
Did you ever hear about this idea of the gut being our “second brain” before? Knowing this, has it affected your nutritional habits in any way? Share your comments below – I’d love to hear what you have to say about it!
References (and my many thanks to):
Carpenter, S. (2012, September). “That Gut Feeling”. American Psychological Association. Retrieved October 3, 2017, from http://www.apa.org/monitor/2012/09/gut-feeling.aspx.
Foster, J.A. (2013, July). “Gut Feelings: Bacteria and the Brain”. Cerebrum: The Dana Forum on Brain Science. Retrieved October 3, 2017, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3788166/.
“Our Gut Microbes Strongly Influence Our Emotional Behaviors”. (2017, July 4). IFLScience. Retrieved October 3, 2017, from http://www.iflscience.com/health-and-medicine/gut-microbes-strongly-influence-emotional-behaviors/.