IBS Basics: What Is IBS (Irritable Bowel Syndrome)?

The best foods for IBS health are those that are gentle on the digestive system. By finding out what foods are your personal triggers, you can learn how to eat meals that are safe for your stomach.

Irritable bowel syndrome (IBS) is common, affecting aas many as 20 percent of Americans, and yet it remains a mystery. No one knows exactly what causes it, and there is no way for a doctor to make a definitive diagnosis. There is no single trigger and no single set of identifying symptoms: The symptoms can come and go in a day, or plague sufferers for months or years. So much uncertainty attached to very real physical discomfort makes coping with IBS frustrating in the extreme. IBS is called a functional bowel disorder, and not a disease, because it doesn’t cause permanent damage, it doesn’t progress to serious illness, and it can usually be controlled with diet and lifestyle changes. There’s another reason to be hopeful even if your case is a persistent one — people with chronic symptoms like yours have been successfully treated with new medications, making the condition less disabling than ever before.

Many people confuse IBS with IBD, which stands for Inflammatory Bowel Disease (talk about acronym confusion!). Although IBD and IBS both affect the intestines and can cause similar symptoms, they are very different conditions. IBD actually refers to a cluster of disorders, but the two major types are Crohn’s disease and ulcerative colitis; both are chronic conditions characterized by inflammation of the intestines, which results from the body’s impaired immune response. Treatment for IBD may require powerful medications to suppress inflammation, and sometimes even surgery. Unlike inflammatory bowel disease, IBS does not involve a dysfunctional inflammatory response, cause permanent damage to the intestines, or increase your risk of colon cancer and other intestinal disorders. Though IBS can certainly be painful and debilitating, it fortunately does not carry the same health risks as inflammatory bowel disease.


The agony of IBS comes from the pain, discomfort, and embarrassing inconvenience of symptoms, which include diarrhea or constipation, cramping, bloating, excess gas, and mucus in the stool. To understand what happens in IBS, imagine a football stadium full of spectators doing “the wave.” If everyone cooperates, you can see the forward progression of the wave as each section stands and then sits again — it’s amazing to see so many bodies working in concert. Now imagine that you have some very nervous spectators — they see the wave coming at them, and they stand up too early, starting a secondary wave. So now the first wave stops midstream. The rhythm is disrupted. Or, imagine that one group stands up for the wave but doesn’t sit back down again. The wave is “stuck,” unable to move forward until the disrupting group decides to sit back down again.

Our intestines are lined with muscles that contract and relax in waves (ah-ha!) called peristalsis, which push the food you eat through the system. Along the way, nutrients are absorbed, and the residual is eventually eliminated in feces. In people with IBS, normal rhythmic waves are disrupted because your nervous system is not communicating effectively with the muscles that control your gut. Sometimes, the bowel contracts too much or too forcefully, so food moves through the intestines too quickly, resulting in diarrhea.

Other times, the intestinal muscles contract but don’t relax again, or they contract very slowly, resulting in constipation. These crazy, out-of-sync muscle movements are behind the pain of IBS, much like muscle spasms in your leg cause the pain of a charley horse. We all have intestinal gas, but for people with IBS, it can become trapped inside, resulting in bloating and distention. Some of my clients with IBS have admitted to buying two wardrobes — an everyday wardrobe and another specifically for their bloated, symptomatic days. Makes perfect sense — who wants to wear a snug pair of jeans or a fitted dress when feeling like the Pillsbury Doughboy? In addition, the intestinal nerves of people with IBS are highly sensitive, so that even minor bloating can have them doubled over in pain.

An individual with IBS might experience just a few of these symptoms — or all of them. Although most sufferers have either diarrhea-predominant IBS or constipation-predominant IBS, some people alternate between diarrhea and constipation. No matter what type of IBS you have, the underlying problem is that the rhythm of intestinal muscle contractions periodically gets messed up. There is no test for messed-up intestinal waves, however, and the symptoms of IBS are common to many other diseases, so arriving at a diagnosis of IBS is often lengthy and full of guesswork. Your doctor will want to rule out all other possible disorders, including Crohn’s disease, ulcerative colitis, and celiac disease, through a physical examination, blood tests, ultrasound, X-ray of your bowels, and sigmoidoscopy or colonoscopy, in which a lighted flexible tube is inserted into your lower intestines to get an up-close (and personal!) look at your intestinal lining. If there are no other problems, it’s IBS by default. Once you have a diagnosis, you and your doctor can get to work to find a treatment that works for you — IBS can be managed with appropriate diet and lifestyle changes and sometimes medications or behavioral therapy. It’s important to remember that although IBS can be uncomfortable, and strictly speaking there is no “cure,” it also won’t progress into anything more serious.

We don’t know exactly what disrupts the workings of the intestines in the first place, but we do know what can trigger flares of the disorder. Food is a biggie, and I’ll address that in the next section. Aside from food and eating issues, another significant IBS trigger is stress.

Stress can trigger a flare of IBS, and it can make food-triggered IBS symptoms worse. (That’s why many health experts recommend that people suffering from IBS actively explore a variety of ways to de-stress — there might be a terrific way to relax that you just haven’t tried yet.) Some doctors even talk about an IBS personality, one that is noticeably tense and anxious. I’ve seen this is my own practice. The client who comes to mind is Amy, a kindergarten teacher. The first time I saw Amy, I was struck by her rigid body language — every move she made told me that she was a very controlled person. Whether sitting or standing her posture was perfect, and she held her arms close to her body using minimal gestures. She spoke in a clipped, drill-sergeant sort of way. Everything Amy did, she did quickly. She was always on the run doing things for the kids in her class, running errands for her family, getting stuff for her classroom, and gobbling down her food. Amy didn’t sit down to eat. If she couldn’t wolf down a meal in five minutes it wasn’t worth eating. The challenge with Amy was getting her to recognize her food triggers, and also — perhaps more importantly — helping her to understand that her stressful, on-the-go lifestyle was only making her IBS worse.

On a very basic level, eating quickly is risky because you are more likely to swallow air, which can directly lead to bloating and distention. But stress can also stimulate spasms in the gastrointestinal tract — like feeling butterflies in your stomach when rumors about impending layoffs start floating around the watercooler. In people with IBS, those butterflies are on a rampage. Amy’s IBS was certainly made worse by her tense, never-stop, full-of-stress lifestyle. Fortunately, we were able to get her symptoms under control in pretty short order. We identified her food triggers (starchy beans, raw vegetables, gum, and coffee), which eliminated most of her problems, but stress education was the biggest eye-opener for her. Amy had no idea how much her driven personality affected her bowels. Although she still has a way to go, it’s easier for her to relax now that she doesn’t have to worry about whether her diarrhea will strike unexpectedly, and she’s made a determined effort to ease up. Ironically, she’s as driven about finding time to de-stress as she is about everything else, but she’s on her way to achieving the type of balanced life that can keep her IBS symptoms to a minimum.

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