What You Need to Know About IBS

Don't shrug off your symptoms. Learn the different types of IBS and get the skinny on how a "low-FODMAP" diet can help.

A woman sits in bed clutching her stomach, suffering from one of the many different types of IBS (irritable bowel syndrome).

Medically reviewed in December 2020

Updated on March 1, 2021

Irritable bowel syndrome (IBS) is a chronic condition that affects the digestive tract. It is characterized by a group of symptoms that occur at the same time, including abdominal cramping and changes in bowel movements. Though IBS shares some symptoms with inflammatory bowel disease (IBD), the two are distinct conditions. 

The exact cause of IBS is not known, but experts believe that gastrointestinal (GI) conditions like IBS are problems with the way the brain and gut, or GI tract, work together. Brain-gut interaction issues may lead to IBS symptoms. 

IBS can affect anyone, but it’s twice as likely to occur in women as in men, and it most often occurs in people younger than 45 years of age. Here’s what you need to know about the condition. 

There are different types of IBS 
Irritable bowel syndrome can be classified into one of four categories, based on stool consistency. This classification helps healthcare providers (HCPs) accurately treat symptoms. 

  • IBS with constipation (IBS-C) is characterized by stool that's hard or lumpy at least 25 percent of the time and loose or watery less than 25 percent of the time. 
  • IBS with diarrhea (IBS-D) is characterized by stool that's loose or watery at least 25 percent of the time and hard or lumpy less than 25 percent of the time. 
  • IBS with mixed bowel habits (IBS-M) is characterized by bowel movements that consist of at least 25 percent hard or lumpy stool and at least 25 percent loose or watery stool. 
  • Undefined/unsubtyped IBS (IBS-U) is characterized by stool that's hard or lumpy less than 25 percent of the time and loose or watery less than 25 percent of the time. It’s also common for people in this category to switch between types. 

Symptoms can vary 
IBS doesn’t cause other health problems or damage the gastrointestinal tract, but it does have some uncomfortable symptoms. People with IBS often experience gas, bloating, abdominal pain or discomfort, constipation or diarrhea (or both). 

It’s important to know that weight loss, bleeding, fever and severe pain that does not go away are not symptoms of IBS. If you have these symptoms, talk to your HCP right away, as these signs may suggest other problems.  

Causes are unclear 
The causes of IBS are uncertain, and triggers vary among people. People with IBS often have other health problems, including: 

  • Digestive diseases, such as dyspepsia (indigestion) and gastroesophageal reflux disease (GERD) 
  • Conditions involving chronic pain, such as chronic fatigue syndrome, chronic pelvic pain and fibromyalgia 
  • Certain mental health disorders, such as anxiety or depression 

Diagnosis can be difficult 
There is no single test for diagnosing IBS. Your HCP will likely assess your symptoms, review your medical history and perform a physical exam. You may receive a diagnosis of IBS if you have pain in your abdomen, plus two or more of these symptoms: 

  • Pain that improves or worsens after you have bowel movements 
  • Changes in how often you have bowel movements 
  • Changes in the way your stools look 

Your HCP will also consider the duration of your symptoms in making a diagnosis. You may have IBS if you’ve had symptoms at least once a week over the previous 3 months and your symptoms began at least 6 months ago. 

It may be necessary for your HCP to order tests to rule out other conditions. You may need a blood test to check for celiac disease or a stool culture test to look for a potential infection. You might also be advised to get a colonoscopy to check for cancer. This is particularly the case if you are over 45 years of age, if you experience sudden and unexplained weight loss or if you have bloody stool or an abnormal blood test.  

Dietary changes may help 
The goal in treating IBS is eliminating the symptoms. But treatments aren’t one-size-fits-all. Individuals may need to manage symptoms with a combination of methods. 

Fiber-rich diets can help alleviate diarrhea and constipation but may increase bloating. There are two main types of fiber: 

  • Soluble fiber dissolves in water and is found in oats and many fruits and vegetables. 
  • Insoluble fiber does not dissolve in water and is found in seeds, whole grains and root vegetables. 

Beans contain both soluble and insoluble fiber. Depending on the type of bean and the way the beans are prepared, they may be tolerated by people with IBS. 

Research suggests that choosing soluble fiber for IBS may be best, since it's more helpful than insoluble fiber in relieving symptoms. Consult with your HCP before adding foods with fiber to your diet. When you do, it’s advisable to add them slowly, in increments of 2 to 3 grams of fiber per day, to prevent bloating and gas. 

Think about FODMAPs 
Some people may benefit from adopting what’s known as a low-FODMAP diet for their IBS. FODMAPs (also known as fermentable oligo-, di-, monosaccharides and polyols) are gas-producing carbohydrates that are often hard to digest. High-FODMAP foods include: 

  • Vegetables and legumes such as asparagus, beans, cabbage, cauliflower, garlic, mushrooms and onions 
  • Fruits such as apples, apricots, cherries, pears, plums and watermelon (or juices made from these fruits) 
  • Dairy products such as milk, soft cheeses, yogurt, custard and ice cream 
  • Foods that contain wheat or rye 
  • Honey and foods with high-fructose corn syrup 
  • Products containing sweeteners with names that end in “-ol” (such as sorbitol, mannitol and xylitol) 
  • Canned fruit that comes in natural fruit juice, as well as large amounts of dried fruit 

A low-FODMAP diet is not a list of foods to avoid completely. Instead, your HCP may advise that you eliminate foods that are high in FODMAPs, then re-introduce them one at a time to determine what is best for your diet. Note that getting enough dietary fiber can be challenging on a low-FODMAP diet, so it’s important to consult with your HCP before trying this strategy. 

Some people with IBS may also have more symptoms after eating gluten, a protein found in wheat, barley and rye. Your HCP may recommend that you avoid foods that contain gluten. 

Caffeine is also a potential trigger for IBS, so you may be advised to you limit your intake of foods such as coffee, tea, soda and energy drinks. 

Reducing stress may help as well 
Strong emotions, such as those arising from stress, anxiety, depression and fear, may trigger or worsen a bout of IBS. Your HCP may suggest you try mental health therapies to help relieve IBS symptoms. These may include cognitive behavioral therapy (CBT), relaxation training or even hypnotherapy (hypnosis). Lifestyle changes that reduce stress—like getting more exercise, seeking social support and establishing better sleep habits—can also help manage symptoms. 

There is some evidence that probiotics may help improve IBS symptoms in some patients. Your HCP can advise whether taking probiotics is right for you, and if so, what dosage makes sense. 

If lifestyle approaches don’t improve your condition, your HCP may suggest you take over-the-counter or prescription medications to manage IBS.

Article sources open article sources

National Institute of Diabetes and Digestive and Kidney Diseases. “Irritable Bowel Syndrome (IBS).” Published November 2017.
National Institute of Diabetes and Digestive and Kidney Diseases. “Eating, Diet, & Nutrition for Irritable Bowel Syndrome.” Published November 2017.
American Gastroenterological Association. “Irritable Bowel Syndrome (IBS).” Published July 2017.
Ford AC, Moayyedi P, Chey WD, et al. “American college of gastroenterology monograph on management of irritable bowel syndrome.” Am J Gastroenterol. 2018;113(Suppl 2):1-18.
International Foundation for Gastrointestinal Disorders, Inc (IFFGD). “The Low FODMAP Diet Approach: Measuring FODMAPs in Foods.” Published November 20, 2017. 

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