Recent research from the University of Texas Medical Branch at Galveston, published in the American Journal of Physiology — Gastrointestinal and Liver Physiology, links early-life stress with increased norepinephrine in the upper gut, potentially leading to indigestion and anxiety problems later in life (in rats). Press release. Study (Full text PDF).

Basically, what they showed is that inflammation in the gut (which can be caused by all sorts of different factors, including stress) when a rat is in its infancy, led to nerves around the gut pumping out more norepinephrine, a stress hormone, when the rats were older. That resulted in functional dyspepsia and “anxiety-like” symptoms.

It’s quite common in mental health communities to hear that people dealing with anxiety disorders are also struggling with their gut. I get messages about it all of the time. As the study mentioned above points out, inflammation in the gut could also be caused by something like an infection or malnutrition, not necessarily psychological stress. We can’t blame anxiety problems for digestion problems or the other way around, but there’s the potential for bi-directional comorbidity. A lot of studies have tried to find a connection between things like IBS and anxiety but I’d say they’re pretty inconclusive. Having one doesn’t necessarily require the other but it’s possible they can become linked in a stomach churning feedback loop.

This study also hints at a common challenge when tackling recovery from anxiety disorders and symptoms like panic attacks: the sympathetic nervous system will fire on all cylinders in reaction to perceived danger even when you’re rationally aware that something isn’t dangerous and you’re learning how to change how you think about that danger. Physical habituation lags behind cognitive changes. That changes the more you practice, but when you’re getting over an anxiety disorder, it’s not uncommon to experience anxiety symptoms in your body long after you’ve cut out a compulsion. You might experience the butterflies in your stomach even though the intrusive thoughts don’t pop into your head anymore. It’s like your body remembers you should be anxious in these situations (even though you know you don’t need to be any longer).

So, in your head, you might be accepting some uncertainty and you’re walking into an experience you would have avoided in the past because of anxiety. Other parts of your brain and nervous system, however, pick up that you’re in that environment you previously avoided. They start to fire warnings–they get ready for a fight or flight response. Unfortunately, that means releasing stress hormones and, if you’re like one of the rats from this study, that could mean releasing more stress hormones in your gut because of experiences in your youth, and BAM! You’ve got indigestion. Then what happens? You start to judge that internal experience, you worrying about having an accident. Your fears–the reason you avoided this situation in the past, is about to come true! Maybe you’ll crap your pants or you’ll vomit on somebody. It’ll be so embarrassing and EVERYBODY will talk about you FOREVER. That make you anxious. You have a real issue to deal with now! It’s not just your thoughts! And that creates more anxiety, which leads to more indigestion, which leads to more compulsions, more fear, and the cycle continues.

The thing to keep in mind (or in your gut) with something like this, is that the study doesn’t indicate whether these types of changes are permanent. Rats are notoriously non-compliant when it comes to doing therapy. Guts can change just like brains. Learning how to handle triggers in a healthy way could lead to not experiencing the same levels of anxiety and stress, which would theoretically lead to not experiencing the same norepinephrine cascade from the nerves.

Personally, my gut works so differently (in a better way) after recovery from mental illness than it did before, and I didn’t even think I had a problem. It’s not something I would have brought up with my doctor because it was just normal, like feeling anxious all of the time.


What experiences have you had with your gut and anxiety?

John H Winston, Sushil K. Sarna. Enhanced sympathetic nerve activity induced by neonatal colon inflammation induces gastric hypersensitivity and anxiety-like behavior in adult ratsAmerican Journal of Physiology – Gastrointestinal and Liver Physiology, 2016; ajpgi.00067.2016 DOI: 10.1152/ajpgi.00067.2016

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