Irritable bowel syndrome (IBS)

Irritable bowel syndrome (IBS) is a long-term condition in which the bowel works and feels differently than it should. The gut looks normal on tests, but it is more sensitive and its muscles move food along too fast, too slow, or unevenly. Studies suggest about 12 percent of people in the United States have IBS. If you live with it, you are far from alone, and your symptoms are not "all in your head." Dr. Pimienta treats IBS for adults in Los Angeles, and works with each person on a plan that fits their daily life.

What is irritable bowel syndrome?

Doctors diagnose IBS by a pattern of symptoms. In plain words, you likely have IBS if:

• You have belly pain on at least one day a week, on average, over the last three months
• The pain is linked to your bowel movements: it gets better or worse when you go, or it comes with a change in how often you go or in how your stool looks
• The symptoms started at least six months ago

Other common symptoms include bloating, gas, mucus in the stool, and a feeling that you have not fully emptied your bowels. Symptoms often come and go, with good weeks and bad weeks.

What are the types of IBS?

IBS is grouped by your most common stool pattern, because treatment differs for each:

Your type can change over time, which is one reason follow-up visits matter.

What causes IBS?

There is no single cause. IBS is now understood as a disorder of gut-brain interaction. The gut and the brain constantly send signals to each other through a large network of nerves. In IBS, that conversation is out of tune: normal amounts of gas or stretching can feel painful, and the bowel's muscles may squeeze too hard or too little.

Things that can set off or worsen IBS include:

• A past bout of food poisoning or a gut infection (some people develop IBS after one)
• Certain foods, especially some carbohydrates that are poorly absorbed (FODMAPs, explained below)
• Stress, anxiety, poor sleep and big life changes
• Hormone changes, such as during the menstrual cycle
• Changes in the gut's bacteria

Stress does not cause IBS on its own, but it turns up the volume on symptoms, much like it can worsen a headache.

Which symptoms need more testing?

Some symptoms are not typical of IBS and point to other conditions that need to be checked. Tell Dr. Pimienta if you have:

• Blood in your stool, or black stools
• Weight loss you cannot explain
• Anemia (a low blood count) or low iron
• Symptoms that wake you from sleep
• Fever, or diarrhea that does not stop
• A family history of colon cancer, inflammatory bowel disease or celiac disease
• Symptoms that started later in adult life, for example after age 50

How does Dr. Pimienta diagnose IBS?

IBS is diagnosed from your symptoms, a physical exam and a few well-chosen tests, not by doing every test available. This approach is recommended by GI guidelines, and it spares you tests that do not help. Depending on your symptoms, Dr. Pimienta may order:

• Blood tests, such as a blood count and a test for celiac disease, especially when diarrhea is part of the picture.
• Stool tests to check for inflammation in the bowel, which can point toward inflammatory bowel disease instead of IBS, or for certain infections.
• Other tests that may be arranged when your history suggests them, such as breath tests for certain food sugars.
• Colonoscopy if you have warning signs, or if you are due for colorectal cancer screening anyway.

How is IBS treated?

Most people do best with a combination of approaches. You and Dr. Pimienta decide together where to start, then adjust at follow-up visits.

The low-FODMAP diet, with a dietitian

FODMAPs are certain carbohydrates found in foods such as onions, garlic, beans, wheat, some fruits, milk and sugar-free sweeteners. They draw water into the bowel and are fermented by gut bacteria, which can cause pain, gas and changes in stool. The diet has three phases and works best with a registered dietitian:

1. Cut back

   For about two to six weeks, you limit high-FODMAP foods to see whether symptoms improve.

2. Bring foods back

   One group at a time, you add foods back to learn which ones bother you, and how much.

3. Personalize

   You eat as wide a diet as possible, avoiding only your own triggers. The diet is not meant to be strict forever.

Fiber

Soluble fiber, such as psyllium, often helps IBS symptoms, especially constipation. Start with a small amount and increase slowly. Insoluble fiber, like wheat bran, can make bloating and pain worse for some people.

Medicines matched to your type

• For constipation (IBS-C): osmotic laxatives, which draw water into the bowel, and prescription medicines that increase fluid in the gut.
• For diarrhea (IBS-D): anti-diarrheal medicines, certain prescription medicines including a gut-focused antibiotic, and medicines that bind bile acids for some people.
• For pain and cramping: antispasmodics, which relax the bowel muscles, and peppermint oil capsules.
• Gut-brain neuromodulators: low doses of certain medicines first developed as antidepressants. At these low doses they calm the nerves of the gut and ease pain. Being offered one does not mean anyone thinks your pain is imagined.

Gut-directed psychotherapy and stress care

Therapies that work on the gut-brain connection, such as cognitive behavioral therapy (CBT) and gut-directed hypnotherapy, have good evidence for IBS. They teach skills that lower the gut's sensitivity. Regular exercise, steady sleep and stress relief help many people too.

Living with IBS

• Eat regular meals, and do not skip breakfast, which helps the bowel keep a rhythm.
• Keep a food and symptom diary for a few weeks to spot patterns.
• Move every day; even a walk after meals can help.
• Limit caffeine, alcohol and very fatty meals if they trigger symptoms.
• Plan ahead on bad days: know where restrooms are, and carry what you need.
• Give each change a few weeks before deciding whether it works.

Questions patients ask

References

1. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Irritable Bowel Syndrome (IBS).
2. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Treatment for Irritable Bowel Syndrome.
3. American College of Gastroenterology. ACG Clinical Guideline: Management of Irritable Bowel Syndrome. American Journal of Gastroenterology, 2021.