So, let’s start with some basic info: Irritable Bowel Syndrome, aka IBS, is a gastrointestinal disorder characterized by abdominal pain and changes with a person’s bowel movements in the ABSENCE of any detectable abnormality of the colon structure or biochemistry.

In other words. . . normal scope and normal labs despite symptoms.

This is different than Inflammatory Bowel Disease (aka IBD) such as Crohn’s and Ulcerative colitis. It is also somewhat different than Collagenous (Co – laj – e – nus) colitis, which will also have a normal scope, BUT the colon cells will show signs of inflammation under the microscope.

Now, back to Irritable Bowel Syndrome (IBS):


  • Cramping abdominal pain with diarrhea, constipation, or alternating. . . one then the other.
  • Intensity and periods of ‘flares’ are variable from person to person and from flare to flare.
  • Abdominal pain can be mild to severe.
  • IBS can be accompanied by nausea and vomiting during a flare.
  • Fatigue can also be associated with IBS.


People with IBS typically will be:

  • IBS with constipation (aka. . . IBS-C)
  • IBS with diarrhea (aka. . . IBS-D)
  • Mixed IBS (aka. . . IBS-M)

Pain can be made worse or alleviated with defecation. Pain is often intensified by emotional stress and certain foods that can be unique to the individual. Often, abdominal bloating with increased gas production is also seen and can result in increased flatulence or belching.

Who’s Affected?
The number of peeps in North America affected by IBS is estimated to be between 10-15%. . . so, between 57.9 and 86.8 million people. One out of every five Americans is affected by IBS. The number of peeps affected when researchers pooled data from eight international studies was estimated to be 11%

IBS is the most common diagnosis seen by Gastroenterologists. But despite the large number of people affected, less than 10% of those with it have been officially diagnosed. Typically, symptoms begin when a person is in their twenties. Of note, the incidence of IBS in those over fifty years of age was 25% lower, and women were more affected than men.

So What Causes It?
At this point the actual cause is unknown. It does appear that the cramping with diarrhea or constipation is related to the amount of fluid absorbed in the colon. If too much fluid absorbed (or leaves the colon), the consequence is constipation. The faster the movement of the colon is pushing things through, the less fluid is absorbed and the consequence is diarrhea. What is known is that it is is an abnormality of the colon contacting, or squeezing in order to move metabolic waste through the system.

There are many working theories as to what causes the changes. These include. . .

  • Altered colon motility (or, the movement of the colon)
  • Visceral hypersensitivity (the lining of the colon is hypersensitive)
  • Post-infectious reaction
  • Brain-Gut interaction
  • Change in bowel bacteria
  • Food sensitivity
  • Carbohydrate malabsorption (abnormal absorption of carbs)
  • Inflammation of the intestines (an autoimmune issue)

Serotonin and serotonin regulation is now thought to be a major player in IBS.

(Remember Serotonin? Our “happy” neurotransmitter. Neurotransmitters are chemicals that are released at the end of a nerve. Their release is caused by a nerve impulse, a trigger if you will. Once the neurotransmitter is released, it causes other actions in our bodies to occur.

Serotonin is considered by most to be a neurotransmitter, but some consider it a hormone. It is found in the brain and spinal cord, the platelets (which are a type of blood cell), and the intestines. Most of the serotonin is found in the gut, the digestive system. Serotonin is believed to help regulate mood and social behavior, appetite and digestion, sleep, memory, and sexual desire and function.)

Okay, but what’s the link between Serotonin and IBS?
Well, Serotonin is a major regulator for gut movement and for sensing changes in our gut. Moreover, the release of serotonin in the blood appears to be decreased in people with IBS-C (constipation) and increased in people with IBS-D (diarrhea) Further studies are needed, but certainly, with the recent work on serotonin and IBS, it would appear that the most logical cause is the Brain-Gut connection.

This might also explain the associated conditions that are often seen with IBS, which include:

  • FMS
  • Chronic Fatigue Syndrome
  • Reflux / Heartburn
  • Non-cardiac chest pain
  • Depression
  • Anxiety

Be sure to check out Part 2 of my IBS series, where I will be talking about current treatment options, both traditional and alternative.




0 0 votes
Article Rating