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Monday, December 3, 2012

IBD Awareness Week: The Role of Stress, Part 1

5:32 AM Posted by Tiffany Taft , ,
Yesterday I tweeted the statistic that 75% of people with IBD report that they believe stress was a contributing factor to their developing Crohn's disease or Ulcerative Colitis.  That stat came from a 2012 review article of psychological issues in IBD, published in the journal Gastroenterology Research & Practice.  It prompted an exchange with one of our followers about a common misconception that stress causes IBD, and how this belief can lead to stigma in that the person with IBD has done something to bring the disease on themselves.

This is a tricky topic because, as I tell every person that I see, stress doesn't necessarily cause your condition but stress isn't good for any chronic illness - whether it's hypertension, ulcerative colitis, lupus, or migraine headaches.  Some people readily endorse the connection between stress and symptoms, while others deny any connection whatsoever.  So what's the deal?

First off, we ALL experience stress.  Every day.  Unless you perpetually live in a Corona commercial.  And this isn't necessarily a bad thing.  Stress is a motivator - to a point.  Because I like pretty graphs, here's a common representation of stress's effect on our ability to get things done:

The "Stress Curve"
As you can see from the graph, too little and too much stress each have their own negative effects.  However, the red area on the right side is when stress levels begin to exceed our internal resources and is when we start to see detrimental effects including changes to our immune system functioning.  There's an entire field that studies this, called psychoneuroimmunology.

Before I get into that, which do you think is harder on your body?  Chronic daily hassles or big-time stressful life events like a death of a loved one or losing your job?  Most people to whom I've asked this question say big events, because we always hear about Uncle Ralph having a heart attack after something major happened in his life.  When actually it's the chronic daily hassles that produce the most wear and tear.  Things that are enough to get you agitated - being stuck in traffic when you're running late as it is; an annoying co-worker; getting an unexpected medical bill; a cranky toddler.
Be glad you don't live here...
It's the cumulative effect of chronic daily hassles that leads to the greatest wear and tear on your body from stress; things that some people may not really consider stress, per say, because they're not one of the bigger problems we could experience in life.

So what happens to your immune system when you're experiencing stress?  Well, a lot of things.  Some recent studies, including one published in the past month in the journal Gastroenterology (which is one of the highest ranked GI journals), talk about the role of the stress response and the hypothalamic-pituitary-adrenal (HPA) axis.  There is mounting evidence that stress can affect systemic and mucosal inflammation in the digestive system.

Wait, what the heck is the HPA axis?  Some of you may have heard about the mind-body connection, or even the brain-gut connection.  The gist is that our nervous system is intricately wired into the rest of our body (duh), and when chemicals are released in response to stressful situations this sends shockwaves through various pathways between the brain and the body, resulting in a myriad of physical symptoms.  Let's break down HPA:

Hypothalamic:  In every one of our brains is a structure called the hypothalamus.  It's remarkable what this relatively small area of the brain does, including controlling:  body temperature, sleep, hunger, thirst, sexual behavior, and emotional responses.  Whew.  The hypothalamus serves as a relay station for its neighbor, and the next part of the HPA...

Pituitary (Gland):  Remember 9th grade biology?  The "master" gland.  This thing does everything.  Well, almost.  It manages the release of 9 major hormones that control growth, blood pressure, temperature, pain regulation, water absorption, and energy conversion.  It also releases a hormone that's associated with levels of cortisol (the stress hormone) in the body.  This leaves the last part of the HPA...

Adrenal (Glands):  One sitting on top of each kidney.  The adrenal glands release adrenaline,  which controls blood pressure and metabolism.  But is more commonly known as being part of the fight-or-flight response.  The "adrenaline rush."  You've experienced it so I don't need to go into it in more detail.  If you're rusty, think of something you're afraid of and then go try and do it.

These 3 areas of your body are all wired together to create the HPA axis.

Think of it as your body's stress superhighway.
Researchers are identifying through both basic science experiments with mice and clinical studies with people that the HPA axis is somehow involved in the inflammatory process in the colon.  Yes, there are mice running around in labs with Ulcerative Colitis.

Quite possibly the cutest thing you'll see this week.
One theory is that the HPA axis in people with IBD doesn't work properly, which  may be the result of chronic inflammation derailing the feedback loop between the immune system and the HPA axis. So hormones released by the pituitary gland that would normally be anti-inflammatory don't result in this response. Another theory is that the autonomic nervous system, which is involved in the fight-or-flight response (among other things), is hyperactive in people with IBD. Yet another theory is that changes in receptors in the intestines that respond to a chemical released by the pituitary gland result in reduced water absorption and increased mucus production.

Conclusions?  The jury is still out in the research community what the role of stress is in IBD, but the trend is toward an understanding that it does play a role, at least in disease flare-ups.  Anecdotally, up to 90% of people with IBD endorse this idea.  But it's difficult to say if stress plays any role in the onset of IBD in people who are predisposed to developing it.  And if research does, one day, find that stress is indeed one of the several triggers of the start of IBD (and other autoimmune conditions for that matter), what might that mean for the way IBD is perceived by others?  Will it increase the stigma that already exists?

In Part 2 I'll talk about the Brain-Gut connection and the role stress plays there.

source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1774724/