Irritable Bowel Syndrome

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is irritable bowel syndrome?

Irritable bowel syndrome (IBS) is a gastrointestinal disorder that produces abdominal pain, bloating, flatulence (gas), cramping, constipation, and diarrhea. Two forms of IBS are common: one that is accompanied by bloating, constipation, and abdominal fullness, and another in which diarrhea is present. Although IBS is not life-threatening, its symptoms can severely erode quality of life and may even be disabling.

IBS is one of the most common syndromes in the United States, affecting 10 to 15% of the population. It is more common in women than men, and it usually begins before the age of 35. No specific anatomic abnormalities have been linked to IBS or any specific cause, but there are symptom triggers. There is no cure for IBS. Its symptoms are managed by medication, diet, and lifestyle changes. Unfortunately, up to 70% of patients with IBS do not get the proper treatment they need.

People with IBS often report that stress management and activities, such as yoga and meditation, can have a calming and positive effect on their condition. Medications that may be prescribed for IBS include antidepressants, antidiarrheals, antispasmodics to control spasms in the colon, and fiber supplements. Dietary modifications, such as limiting dairy and gluten intake, can be helpful for some people.

Irritable bowel syndrome itself is not an emergency situation, but persistent diarrhea, a common symptom of the condition, can result in serious dehydration. Seek immediate medical care (call 911) for serious symptoms, such as severe abdominal pain, inability to pass gas or stool, vomiting blood, or blood in stool.

Seek prompt medical care if you are being treated for irritable bowel syndrome but mild symptoms recur or persist.

What are the different types of irritable bowel syndrome?

The three forms of irritable bowel syndrome are based on bowel movements. One form does not appear to be more common than the others. Types of IBS include:

  • IBS with constipation (IBS-C), including abdominal pain and bloating

  • IBS with diarrhea (IBS-D), including abdominal pain and urgency

  • IBS with mixed bowel habits (IBS-M)

What are the symptoms of irritable bowel syndrome?

Symptoms of irritable bowel syndrome (IBS) primarily affect the gastrointestinal system and include abdominal pain, discomfort, bloating, and fullness. IBS can occur with constipation and bloating as the main symptoms or with diarrhea, watery stools, and urgency.

Common symptoms of IBS with constipation (IBS-C)

The form of IBS that is characterized by constipation may include the following symptoms:

Common symptoms of IBS with diarrhea (IBS-D)

The form of IBS that is characterized by diarrhea may include the following symptoms:

  • Abdominal pain or cramping

  • Diarrhea

  • Loose, watery stools

  • Urgent need to pass stool

Serious symptoms that might indicate a life-threatening condition

In some cases, irritable bowel syndrome associated with persistent diarrhea can cause severe and sometimes life-threatening dehydration. Seek immediate medical care (call 911) for any of these life-threatening symptoms including:

  • Bloody stool (blood may be red, black, or tarry in texture)

  • Inability to pass stool or gas

  • Severe abdominal pain

  • Vomiting blood, which may resemble coffee grounds

What causes irritable bowel syndrome?

The exact cause of irritable bowel syndrome (IBS) has not been determined, although there are several theories. One theory is that IBS may be an immune disorder, or one in which the intestines of the affected person are highly sensitive in responding to stress and bacteria. Certain foods are thought to trigger IBS flare-ups, including dairy products and gluten, which is present in wheat, barley and rye.

The epithelial layer, or cell lining, of the large intestine controls the amount of fluid in the bowel. In IBS, there appears to be a disruption in the function of fluid absorption. This can result in excessive fluid in the colon, which causes diarrhea and watery stools. Or, if the lining of the colon absorbs too much fluid from the colon contents, the stool may become dry, leading to constipation.

Bacteria in the intestinal tract have been found to have a connection to IBS. Some people develop IBS following bacterial gastroenteritis, which is inflammation of the gastrointestinal (GI) tract caused by a bacterial infection.

Another theory of IBS points to a potential role of serotonin, a chemical that transmits nerve signals from one part of the body to another. Excessive levels of serotonin may result in diminished bowel movement and motility function, producing the symptoms of IBS.

IBS can be brought on by certain medications and hormonal influences. Increased estrogen seems to affect bowel activity, and symptoms can worsen during menstruation. However, estrogen itself does not seem to be the reason why more women than men develop IBS. One theory is that women may be more hypersensitive than men to the sensations from the intestines.

Symptoms can occur from a few times a week to once a month. IBS can also go away for months or years and suddenly return. Symptoms may get worse for a person under stress from traveling or during a change in daily routine. They also may get worse if you have an unhealthy diet or after you eat a big meal. Keeping a diary of what you eat and your symptoms for a few weeks can help you determine if a certain food or time of month causes problems.

Triggers of IBS

Certain foods can trigger IBS symptoms, such as:

  • Alcohol 

  • Beans

  • Cabbage

  • Caffeine

  • Chocolate

  • Fats (both “good” and “bad” fats)

  • Milk products

  • Raw fruit

What are the risk factors for irritable bowel syndrome?

A number of factors increase the risk of developing irritable bowel syndrome (IBS). Not all people with risk factors will get IBS. Risk factors for IBS include:

  • Depression

  • Family history of irritable bowel syndrome

  • Feelings of stress

  • Female sex, although IBS affects male and female children equally

  • History of adult sexual or domestic abuse

  • History of childhood sexual abuse

  • Ingestion of certain foods, such as dairy products or gluten

  • Previous gastrointestinal infections, such as gastroenteritis

What is known about irritable bowel syndrome in children?

Irritable bowel syndrome (IBS) in adults is most well studied, but IBS occurs in children as well. It is the most common gastrointestinal diagnosis made by pediatric gastroenterologists. The risk of IBS in children is greatest if both parents have the condition.

Symptoms of IBS in children are the same as in adults, including:

  • Abdominal pain felt around the belly button, which continues off and on for at least three months

  • Bloating and flatulence (gas)

  • Cramps

  • Feeling sick to stomach (nausea)

  • Loss of appetite

  • Urgency to produce a bowel movement, with fear of not making it to the toilet in time

  • Sensing there is stool that needs to come out but doesn’t

  • Stool changes, such as diarrhea or constipation or both

There is no test to diagnose IBS. Doctors diagnose it by the patient’s symptoms and by ruling out other possible causes. Seeing a digestive specialist (gastroenterologist) improves the likelihood of getting an accurate diagnosis.

Dietary changes are the first line of IBS treatment in children. To calm intestinal cramping, the doctor may prescribe antispasmodics. There are also remedies and medications for diarrhea and constipation.

The discomfort and potential embarrassment of IBS may prompt some kids to skip school and avoid social situations. With time, both of these practices can lead to poor self-esteem and depression.

These strategies may help your child live better and increase their control over the condition:

  • Learn about IBS.

  • Keep a food, liquid and activity diary to identify triggers.

  • Avoid triggers, which may include dairy, gluten, and fatty foods.

  • Avoid caffeine, including energy and “sports” drinks containing caffeine.

  • Eat small but frequent meals.

  • Consider therapy, which can teach your child healthy, positive ways to process unpleasant feelings and help prevent low self-esteem, anxiety and depression.

  • Consider alternative treatments, such as biofeedback and hypnosis.

What are the diet and nutrition tips for irritable bowel syndrome?

What you eat and the way you eat it may trigger irritable bowel syndrome (IBS) symptoms. Eating large meals can cause cramping and diarrhea, so eating smaller meals more often helps some people with IBS. Eating quickly can cause you to swallow air, which can cause belching or gas.

Fiber for constipation

If constipation is one of your main symptoms, adding fiber to your diet can help loosen stools and reduce abdominal pain. At first, fiber will increase the amount of gas in your system, so add fiber gradually. Over time, the body adjusts to the effects of fiber and the gassiness will decrease. Fruits, vegetables and whole grain breads and cereals are good food sources of fiber. Your doctor may recommend a fiber supplement. Some experts believe that the fiber methylcellulose creates the least amount of gas, and brands of this fiber are often recommended for people with IBS. Psyllium is also a good source of fiber.

IBS trigger foods to avoid

The foods that trigger IBS vary considerably between people. In general, liquids and foods to avoid with IBS include:

  • Alcohol

  • Beans

  • Cabbage

  • Caffeine

  • Chocolate

  • Dairy

  • Fat

  • Raw fruit

Low-FODMAP diet

There is evidence that a low-FODMAP diet can help prevent IBS symptoms. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. The body does not readily absorb these types of carbohydrates, so they cause excess fluid and gas, leading to abdominal pain and bloating.

Low-FODMAP diet elements include:

  • Cereals and breads low in oligosaccharides, including gluten-free and spelt breads and cereals (spelt contains gluten, but it may be easier to digest than wheat); avoid wheat products

  • Fruits low in fructose and/or polyols, including bananas, berries, melons (except watermelon), kiwis, grapes, and citrus fruits; avoid canned fruit in natural juice and peaches, pears, apples, apricots, avocados, plums

  • Gelato, sorbet and lactose-free ice cream 

  • Hard cheeses; avoid soft cheeses like brie and goat cheese

  • Lactose-free milk and rice milk; avoid cow milk

  • Maple syrup and golden syrup; avoid high-fructose corn syrup

  • Sweeteners, including sugar (sucrose), glucose, and artificial sweeteners not ending in “-ol”; avoid sorbitol, maltitol, and other sweeteners ending in “-ol” 

  • Vegetables low in oligosaccharides, including carrots, celery, corn, green beans, lettuce, and bok choy; avoid broccoli, cabbage, onions, peas, Brussels sprouts, asparagus, and garlic (garlic-infused oil is OK)  

Ask your healthcare provider for guidance before making significant changes to your diet. Working with a registered dietitian may be helpful in developing a healthy and nutritious diet plan for IBS.

What are some conditions related to irritable bowel syndrome?

Irritable bowel syndrome is considered a functional gastrointestinal (GI) disorder. These disorders stem from problems with the gut-brain axis, the line of communication between your brain and your enteric nervous system, which involves nerves and hormones in your GI tract. Miscommunication along the gut-brain axis can make the intestines very sensitive, leading to bowel contractions and cramps. This, in turn, can lead to changes in bowel habits and the overall symptoms of IBS. Other names for IBS include spastic colon and “nervous stomach.”

Although the causes are different from those of IBS, these conditions can produce IBS-like symptoms:

  • Celiac disease, a genetic autoimmune condition that causes the body to overreact to foods that contain gluten. The resulting inflammation can damage the gastrointestinal lining, leading to GI symptoms and nutritional deficiencies. 

  • Inflammatory bowel disease, including Crohn’s disease and ulcerative colitis. These conditions cause diarrhea, constipation, and abdominal pain. They are autoimmune conditions that damage the lining of the bowel.

  • Lactose intolerance, a deficiency in an enzyme (lactase) necessary to digest lactose, leading to GI symptoms when you consume milk and milk products

How do doctors diagnose irritable bowel syndrome?

There is no screening test for IBS. Instead, a doctor will ask questions about your symptoms; if they have a certain pattern, the doctor may diagnose IBS. It is the most common disease gastroenterologists diagnose.

The doctor may also perform tests to make sure symptoms are not from another condition. Your provider will ask about your medical history, dietary habits, and symptoms. Your doctor will examine you, testing your abdomen for tenderness and feeling to determine whether internal organs are larger than normal. The doctor will check for fever or weight loss. If you have any of these signs, you may have something other than IBS.

You may be asked to stop eating or drinking certain foods for up to three weeks to determine if your diet is contributing to your symptoms. (For example, your doctor may ask you to eliminate milk products if he or she suspects lactose intolerance.)

Tests the doctor may order include:

  • Blood tests

  • Stool sample, to check for blood or evidence of infection

  • Sigmoidoscopy, in which a flexible, lighted tube with a tiny camera on the end is inserted into the rectum and up the left side of the colon; or a colonoscopy, in which a longer tube examines the entire colon

  • Barium X-ray, when you drink a chalky solution or it is pumped into the rectum to coat the inside of the gastrointestinal tract and highlight abnormalities on X-ray imaging

How is irritable bowel syndrome treated?

Currently, there is no cure for irritable bowel syndrome (IBS). The goal of treatment is to ease the symptoms, remedy any nutritional deficiencies, and reduce the number of recurrences, or flare-ups. Treatment may involve dietary modifications, medication, self-care, and alternative therapies.

Dietary modifications for IBS

One of the most helpful ways to treat IBS is to modify your diet. This can minimize symptoms, or it can reduce the likelihood that an IBS attack will occur. In almost every case of IBS, different foods tend to trigger IBS symptoms. Doctors recommend monitoring what you eat so you can find out what you ate before an attack. After you discover your particular trigger foods, eliminate them from your diet.

Common IBS trigger foods include:

  • Alcohol

  • Cabbage, broccoli, Brussels sprouts, kale, legumes and other gas-producing foods

  • Caffeine

  • Dairy products

  • Fatty foods, including whole milk, cream, cheese, butter, oils, meats and avocados

  • Foods, gums and beverages that contain sorbitol, an artificial sweetener

  • Gluten-containing foods

  • Raw fruits

Dietary modifications and habits that may reduce symptoms of IBS include:

  • Adopting a low-FODMAP diet to reduce intestinal fluid and gas production. FODMAPs are fermentable sugars, including fructose, lactose, oligosaccharides, and polyols, which ultimately increase fluid and gas in the bowel.  

  • Drinking plenty of liquids, especially water

  • Eating a high-fiber diet

  • Eating smaller portions throughout the day instead of large meals

If dietary modifications do not relieve your symptoms, your doctor may prescribe medicine.

Medications for IBS

Depending on the form of IBS and other conditions you have, your healthcare provider may prescribe the following types of medications to treat its symptoms:

  • Antidepressants

  • Antidiarrheals for IBS with diarrhea, such as alosetron (Lotronex), loperamide (Imodium), diphenoxylate (Lomotil and other brand names), and eluxadoline (Viberzi). FDA guidelines advise that eluxadoline should only be taken by patients who still have their gallbladder. Alosetron (Lotronex) is prescribed for IBS with severe diarrhea. The doctor must register with the drug manufacturer and receive training to be a prescriber, and you must sign a form stating that you are aware that life-threatening complications of a blocked, ruptured or damaged bowel may be caused by this medicine.

  • Antispasmodics to reduce cramping

  • Fiber supplementation, such as psyllium (Fiberall, Metamucil) or methylcellulose (Citrucel), for IBS with constipation

  • Intestinal muscle relaxants

  • Osmotic laxatives, such as linaclotide (Linzess) and lubiprostone (Amitiza), for IBS with constipation

  • Pain reducers, such as low-dose amitriptyline (Elavil) and desipramine (Norpramin)

What you can do to improve your IBS

In addition to following your healthcare provider’s treatment plan, you can take self-care measures to improve your IBS including:

  • Exercising

  • Joining a support group to help cope with your symptoms

  • Modifying your diet

  • Practicing stress modification techniques, such as yoga or meditation

  • Sleeping 7 to 8 hours a day 

Alternative and complementary treatments for IBS

Some complementary treatments may help some people in their efforts to deal with IBS. These treatments, sometimes referred to as alternative therapies, are used in conjunction with traditional medical treatments. Complementary treatments are not meant to substitute for traditional medical care. Be sure to notify your doctor if you are consuming nutritional supplements or homeopathic (nonprescription) remedies, as they may interact with the prescribed medical therapy.

Complementary treatments may include:

How does irritable bowel syndrome affect quality of life?

Irritable bowel syndrome (IBS) is a chronic condition that can take a heavy toll on daily living and reduce quality of life. Even though there is no curative treatment for IBS, diet, behavior and medication can help control symptoms. Still, an estimated 70% of people with IBS are not receiving the treatment they need. What’s more, bowel habits are not something people tend to discuss openly, so people with IBS often suffer in silence. There is evidence that people with the diarrhea or mixed type of IBS have a lower disease-specific quality of life than those with the constipation type.

A survey of people diagnosed with IBS showed that a better understanding of the gastrointestinal system in general, the effect of diet on IBS, and IBS treatment options is needed. Many survey respondents mistakenly believed IBS increased the risk of colon cancer. That is not true, but the belief has a negative effect on one’s well-being.

More than 70% of respondents attributed their symptoms to anxiety and stress, which could place an undue burden on them to control stress. They also placed much emphasis on what foods to include and avoid with IBS, which is difficult to pinpoint. The survey also showed the desperation many people have to find something that will relieve IBS symptoms.

The International Foundation for Gastrointestinal Disorders has these coping tips for people living with IBS:

  • Get an accurate diagnosis of your symptoms.

  • Take an active role in your health and well-being. Learn about IBS causes, triggers and treatment options, and discuss them with a healthcare provider. 

  • Understand that IBS does not increase colon cancer risk or shorten life span.

  • Don’t overmedicate. Use medications only to relieve or prevent symptoms. 

  • Consider complementary and alternative therapies in addition to traditional medical treatments.

  • Talk with your doctor about your diet and what, if any, changes might help you.

  • Keep follow-up and regular appointments with your IBS doctor. 

  • Inform your IBS doctor about what you are doing to help your symptoms, including all medications, herbal (plant-based) supplements, alternative therapies, and stress reduction practices. 

What are the potential complications of irritable bowel syndrome?

Complications of untreated or poorly controlled irritable bowel syndrome (IBS) can be serious. You can help minimize your risk of serious complications by following the treatment plan that you and your healthcare professional design specifically for you. Complications of IBS include:

Does irritable bowel syndrome shorten life expectancy?

Many people with irritable bowel syndrome can manage symptoms by altering their diet, reducing stress, and, if necessary, taking medication. It is common for IBS to be a chronic problem, although it resolves in some individuals. Most people are able to live comfortably without developing complications. About 5% of people diagnosed with IBS will receive an additional gastrointestinal diagnosis in their lifetime.

The life expectancy of people with IBS is not shorter than typical life expectancy. It is not associated with an increased risk of death.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Aug 20
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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