In the 1950’s Dr. Thomas Almy, a prestigious gastroenterologist snapped a picture of a live colon responding to the proverbial “butterflies in the stomach.”
Dr. Almy invited a student to take part in an experiment where he used a sigmoidoscope to look inside the student’s rectum and colon. A bystander complicit in the experiment said something about cancer of the colon. Upon hearing this, the student concluded that he must have cancer, at which time his colon started to change color, tense up, and contract rapidly. When the student was reassured that cancer was not his diagnosis, his colon regained its natural color, and relaxed.
This experiment paved the way for a deeper understanding of the visceral processes behind our gut-wrenching experiences. Getting butterflies before a big test or nausea right after a breakup: those feelings are much more than anecdotal. It’s a physiological reality that our emotions and stress physically impact our gut.
Butterflies in Your Stomach: The Gut-Brain Axis and Stress
One of the major breakthroughs in understanding how the central nervous system (CNS) and the gut communicate was the discovery of the enteric nervous system (ENS). The ENS, sometimes called the “second brain,” is a complex system of about 100 million nerves found in the lining of the gut. Both of our brains, so to speak, are in constant dialogue and speak in many “languages” as they send signals to and fro via neural and endocrine pathways that collectively have been dubbed the “Gut-Brain Axis.”
The gut-brain axis plays a prominent role in our overall wellness, and there is significant evidence that it’s susceptible to stress. The route to gut-brain axis dysregulation has many avenues, all of which make the gut more vulnerable to disease.
Stress-induced changes in the physiological functions of the gut include changes in gut motility, mucosal permeability, visceral sensitivity, gastric secretion, and gut microbiota. Changes to gut microbiota are called dysbiosis, which may lead to disease. Many of these stress-induced changes account for the symptoms seen in gastrointestinal disorders.
Functional Gastrointestinal Disorders: When the Gut Acts Up
In my clinical practice, evidence of the gut-brain axis is most visible in the functional gastrointestinal disorders: cases when the gut is acting up and there’s no obvious physical cause, like a tumor or bowel obstruction, for example. This does not mean that GI disorders are all in one’s head, however. A more precise conceptualization is that stress influences the actual physiology of the gut. In other words, psychological factors can impact upon physical factors, like the movement and contractions of the GI tract, causing inflammation, pain, and other bowel symptoms. These disorders often significantly reduce the quality of life. Stress influences the actual physiology of the gut.
Functional gastrointestinal disorders include the better-known irritable bowel syndrome (IBS) and the lesser-known small intestinal bacterial overgrowth (SIBO). They continue to be difficult to treat and often require GI doctors to use multiple treatment modalities and make referrals to other clinicians, including psychologists.
To be clear, the gut-brain connection is complex. For one, it is bidirectional; just like a stressed brain sends signals to the gut, a troubled gut sends signals to the brain, putting someone at greater risk for anxiety and other neuropsychiatric difficulties. Parsing which came first, the stress or the gut distress, becomes challenging and most often this bidirectionality between enteric and central nervous systems is a vicious cycle of great discomfort.
Just like a stressed brain sends signals to the gut, a troubled gut sends signals to the brain, putting someone at greater risk for anxiety and other neuropsychiatric difficulties.
On top of that, many of the FGIDs become chronic conditions, which pose a stressful physical and psychological burden. Many of the patients I treat come see me because having a disorder like IBS primes them for stress that maintains the original symptoms. For example, while stress is a clear player in the origin of GI disorders, “gut-focused” thoughts, emotions, and behaviors start to create stress that reinforces the underlying pathophysiology (i.e., slows motility, visceral pain). For example, my patients have become hyper-vigilant of their heightened visceral pain and then begin to catastrophically appraise their abdominal sensations. Also, their quality of life starts to significantly decrease, many times leading to anxiety and depression.
What You Think About Your Gut Matters
I have a deeply personal connection to the gut-brain axis, and it serves to enhance my professional passion and expertise on the subject. In the winter of 2013, I experienced a feeling of pressure in my stomach after every meal. I felt visceral pain, and it felt difficult to empty my bowels. My heart felt fiery. I wasn’t just bloated—I looked pregnant. I had a belly the size of someone six-months pregnant.
I was otherwise healthy, and thankfully so, and the onset of symptoms made me very anxious. After a multitude of tests ruled-out anything life-threatening, I took a hydrogen breath test that my GI specialist said was indicative of small intestinal bacterial overgrowth (SIBO).
I had never heard of it before, so I began to just refer to myself as a “digestive mess.” It definitely felt like a mess, as SIBO had nonchalantly decided to go camping in my gut, like a pesky parasite sucking the life out of every ounce of normal flora to be found. Camping: as in pitching tents, starting fires, and sleeping in the dark hollows of my alimentary organs (i.e., my gastrointestinal tract).
This was my up close and personal reckoning wit