We've all experienced "gut feelings," knowing something about a situation through intuition, with no logical or intellectual proof. There are many accounts of gut feelings saving lives, or otherwise helping people. It's a known quality of human experience. Recently, however, researchers have found that "gut feeling" is a term more literal than we ever thought: gut feelings come from your actual gut.
A new paper in the journal Physiology by psychology professor Linda Rinaman at Florida State University concludes that gut-to-brain signals are responsible for a large part of our behavior, decisions, and emotions—especially related to avoiding harmful situations. It's an old defense mechanism, and one that we share with our mammalian cousins.
The more we learn about our digestive system, the stranger it becomes. Far from being just where the food goes in and from where the rest goes out, our guts have incredible impacts on our states of mind and our cognitive ability. The human body is a whole greater than the sum of its parts.
The mechanism by which the mind-gut communication occurs is the vagus nerve, a long, winding nerve that runs through our chest and abdomen. The vagus nerve monitors and regulates heart rate, hormone levels, immune system functions, and digestion. It's a two way communicator also, so not only does it bring messages from the brain to our other organs, but it allows our other internal organs to send messages to our brain. That includes those gut feelings, sometimes described as feeling something in the pit of your stomach. That's exactly what you're feeling.
The study says that these gut feelings are a powerful factor in our behavior and decision making process in response to worrisome and threatening stimuli. The defense mechanism usually prompts us to slow down and reassess whatever dangerous situation we're in.
Like any system, however, it can get get thrown out of whack. It being our gut, it's thrown out of whack by the things we eat. Evidence suggests that a poor diet can impact your mood and behavior, worsening conditions like anxiety and depression and impairing your ability to make correct decisions in dangerous situations. The extent of this is not yet well understood. Linda Rinaman explained:
Evidence shows that modifying the diet, perhaps by consuming probiotics, can impact your mood and behavioral state...But how does that work? Does it involve the microbiome that you feed in your gut and how those bacteria send signals back to the brain through the vagus nerve? That area of research has exploded in the last few years and, currently, there are many more questions than answers.
There are lots of other mysteries at play here too. For instance, in patients with depression who do not respond positively to medication, putting a pacemaker-like device into their gut which delivers small electric jolts to the vagus nerve has been highly effective at treating depression when other therapies have failed. Scientists do not know why it works.
It seems the more we learn about ourselves the more questions arise and the more mystifying the answers become. Will we ever know the extent of how our own bodies work? Maybe, or maybe not. Regardless, take care of your gut. It could save your life.