Findings Confirm Close Link between Brain and the Miseries of IBS

As many as one out of five adult Americans experience Irritable Bowel Syndrome (IBS), but the disorder - and its causes - are often misunderstood.

The syndrome can include abdominal cramps, diarrhea at some times and constipation at others, and a frequent sensation that a bowel movement has not produced a complete evacuation.

The discomfort, urgency, and uncertainty of IBS (also referred to as spastic colon) can create a restricted lifestyle in which patients feel the need to be always aware of the location of the nearest toilet. For some people, IBS can be disabling. They may be unable to work, attend social events, or even travel short distances.

"Panic and anxiety are present among some patients," says Reza Shaker, MD, Medical College of Wisconsin Professor of Medicine and Chief of the Division of Gastroenterology and Hepatology. "Social and family life can become disturbed and disrupted." Depression is also frequently associated with IBS.

It is theorized that sex hormones could play a role in IBS, since the disorder tends to be more prevalent among women, especially those of child-bearing age. At the same time, the incidence of IBS is increasing among men, most likely brought about by the stresses of daily life.

There is some good news: "IBS might make life quite uncomfortable, but fortunately its symptoms do not cause permanent damage to the body," says Dr. Shaker. "Quality of life can be diminished significantly, but the disorder does not affect the patient's lifespan."

Colon, Brain Closely Connected
Recent research in which Dr. Shaker has been involved documents the close connection between psychological state and IBS. "We have for the first time, using fMRI (Functional Magnetic Resonance Imaging), shown that the neural circuits and brain cells of IBS sufferers are overly sensitive to some stimuli," he says.

"Just as the psychological state of a patient affects breathing and the beating of the heart, it also affects the gut," Dr. Shaker explains. For example, stress makes the brain more responsive to impulses from the colon.

The major function of the colon is to absorb water, nutrients, and salts from the partially digested food that enters from the small intestine. When the gastrointestinal system is working optimally, an appropriate amount of fluid is absorbed, while enough is left in the colon to ensure an easy elimination.

But in people with IBS, certain stressors or foods can cause the food residue to move too rapidly through the colon. As a result, less fluid is absorbed and more is left to mix with the colon contents, resulting in cramping and diarrhea.

In other cases, stress or food can slow down colon function so too much fluid is absorbed. In this situation there is less fluid available to mix with colon matter and stools become dry, hard, and difficult to eliminate. In other words, the patient is constipated.

Diagnosis is Based on Expertise
The working definition of IBS includes changes in bowel habits, along with pain and discomfort that affect the patient for at least three months. These problems might occur continuously or only at intervals and they are relieved by a bowel movement. "This definition is based on the consensus of specialists who have seen numerous IBS patients and have carefully studied the illness," says Dr. Shaker.

"There are currently no standard clinical tests with which we are able to diagnose IBS," he continues. "Therefore doctors must rely on clinical presentation of symptoms. IBS is a diagnosis of exclusion, that is, we first rule out other problems - such as an obstruction or an overgrowth of bacteria in the gut - before we make a diagnosis of IBS. We base the diagnosis not only on symptoms but on factors such as the patient's age, history, and the duration of the illness."

Self-Diagnosis Is Risky
While the typical symptoms of IBS might be familiar to many people, Dr. Shaker cautions strongly against self-diagnosis. "With the flood of information available today, especially on the Internet, it is tempting for people to start self-diagnosing and self-managing their problems," he notes. "But it's always important to have IBS diagnosed by a doctor to avoid missing treatable or malignant diseases."

Celiac disease, for example, produces IBS-type symptoms but requires a different course of treatment. Celiac disease involves sensitivity to common gluten-containing foods such as bread and other wheat- or barley-based products. A specialist will be able to diagnose this problem and provide the appropriate treatment.

Rarely, IBS-like symptoms might mask more serious conditions such as intestinal lymphoma or Inflammatory Bowel Disease (IBD), a serious disease causing long-term damage to the body.

With a professional diagnosis and medical consultation, patients are encouraged to take responsibility for managing their illness, using reputable websites and other professional materials. (See bottom of page for additional resources.)

Dietary Changes Can Be Helpful
For some IBS patients, a crucial element of treatment is diet modification. Depending on their history and self-reported symptoms after eating particular foods or drinking certain beverages, some fairly simple steps can help alleviate their symptoms. For instance, Dr. Shaker explains, "some patients have lactose intolerance. Others have trouble with gas-forming foods like beans or broccoli, and the gut over-reacts."

Some patients might need to minimize or eliminate their intake of carbonated beverages, chocolate, wheat, rye, barley, alcohol, milk products, or caffeine. Some might also respond favorably to the addition of fiber-rich foods or bulk-forming materials such as psyllium (found in certain foods and also in over-the-counter products such as Metamucil).

Role of Serotonin
Along with changing the diet, "We may add medications that reduce the hyper-responsiveness of the brain-gut connection," says Dr. Shaker. One class of medication that has shown great promise is the neurotransmitter group called SSRIs, or Selective Serotonin Reuptake Inhibitors. Although these medications are known primarily for their use in depression, they also have an effect on intestinal function.

The gastrointestinal tract secretes about 95% of the body's serotonin, while the brain contains the remaining 5%. Recent findings have shown that serotonin and the nerves responsive to it might influence the development of IBS in some people, especially those in whom constipation is dominant. In addition, serotonin plays a significant role in processing symptoms arising from the intestine or colon.

Recent findings have revealed that IBS patients show a lower-than-normal level of serotonin receptor activity, raising the level of serotonin remaining in the GI tract. The significance of serotonin levels in IBS patients is an important focus of current research.

IBS Studies Yield Hope for the Future
"The causes and treatments of Irritable Bowel Syndrome are areas of intense interest among gastroenterologists," Dr. Shaker says. "Recent research has already helped us to understand this disorder and to improve its treatment. We look forward to even greater improvements in the future."

Dr. Shaker practices at the Froedtert & The Medical College of Wisconsin Gastroenterology and Hepatology Clinic.

The following websites provide more information about Irritable Bowel Syndrome:

International Foundation for Functional Gastrointestinal Disorders

National Digestive Diseases Information Clearinghouse

US Department of Health & Human Services/WomensHealth.gov

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.