Written by Stephanie Reese, DO, MS | Reviewed by Karla Robinson, MD Published on August 23, 2022
Key takeaways:
- If you have irritable bowel syndrome (IBS), it usually falls into one of four subtypes. The symptoms you have most often will determine your subtype.
- It’s important to know your subtype because the treatment can differ from one subtype to another.
- Knowing your subtype of IBS helps to target ways that can help decrease the severity of your symptoms.
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Irritable bowel syndrome (IBS) affects up to 10% of people worldwide, and up to 15% of people in the U.S. While IBS is common, it’s not a one-size-fits-all disorder. The symptoms and treatments can vary widely from one person to the next. In fact, there are four different types of IBS that have very different features.
If you’re one of the many people with IBS, understanding your subtype can help. It may provide clues to everything from triggers to the best treatments for you. And it may make living with IBS easier.
What is IBS?
IBS is a gastrointestinal (GI) disorder that typically causes abdominal pain and changes in your stool. For a diagnosis of IBS, you must have had abdominal pain and symptoms for at least 6 months. Your symptoms should also occur at least 1 day a week over a 3-month period.
Typically, you’ll have two or more of the following symptoms:
- Abdominal pain related to a bowel movement
- A change in how often you have bowel movements
- A change in how your stools look
If you have IBS it’s important to find out what subtype you have. To figure out your subtype, you should look at your bowel habits when you’re not taking stool softeners or laxatives. That’s because these medications can change your natural pattern of bowel movements.
What are the 4 subtypes of IBS?
There are four major types of IBS, based on the symptoms you display most during a flare. The subtypes don’t categorize all of your stools, just when your stools are abnormal. We’ll go over the IBS subtypes here.
1. IBS-D (diarrhea)
If you have IBS and more than ¼ of your bowel movements are loose or watery, you have IBS-D. IBS-D is the most common subtype of IBS.
People with IBS-D tend to report a lower quality of life than those with other IBS subtypes. Diarrhea symptoms of IBS-D may be so severe that they have a negative impact on:
- Daily activities
- Body image
- Relationships
Conditions like lactose intolerance and inflammatory bowel disease (IBD) may mimic IBS-D. Your provider can do further testing to make the correct diagnosis.
2. IBS-C (constipation)
If you have this subtype, at least ¼ of your stools are hard or lumpy. Constipation is the main complaint. Many factors can contribute to constipation. So your provider will likely run tests to make sure there isn’t another cause for your symptoms.
People with IBS-C can also struggle with other symptoms as a result of severe stool changes. There may be higher rates of depression and anxiety in those with IBS-C than in other subtypes.
3. IBS-M (mixed diarrhea and constipation)
This subtype has symptoms that alternate between constipation and diarrhea. With IBS-M, your stools are both loose ¼ of the time and hard to pass ¼ of the time.
Another feature that seems unique to IBS-M is the duration of symptoms. Most people with this subtype have symptoms that last for just a few days. In other subtypes, symptoms can sometimes last a bit longer.
4. IBS-U (unclassified)
With IBS-U, your pattern of symptoms is unclassified. In this subtype, your bowel movements don’t meet the criteria for any other subtypes. To have IBS-U, you have diarrhea or constipation less than ¼ of the time with your IBS flares.
What are the treatments for IBS subtypes?
Treatment for IBS will vary from person to person. It can also be dependent on symptoms and subtypes. Many times, IBS treatment uses several approaches. Successful management of IBS symptoms often includes dietary changes, exercise, and medications.
Dietary changes
Dietary changes are one of the first-choice treatments for all subtypes of IBS. Healthcare providers often recommend a diet with foods low in FODMAPs (fermentable oligo-di-monosaccharides and polyols).
Low-FODMAP foods are easier to digest, and they’re less likely to cause bloating and IBS flares. On the other hand, high-FODMAP foods can cause excess gas, which can worsen IBS.
Researchers estimate that for 30% of people with IBS, a low-FODMAPs diet alone will not improve your symptoms. But most people find a low-FODMAPs diet helpful.
Some examples of low-FODMAP foods include:
- Gluten-free bread and crackers
- Lactose-free milk (like soy and almond milk)
- Eggs
- Nuts
- Some fruits (like pineapple, banana, and strawberries)
- Certain vegetables (like spinach, cucumber, and eggplant )
Some high-FODMAP foods you may want to avoid with IBS include:
- Rice
- Some fruits (like apples, pears, and mango)
- Certain vegetables (like onions, cauliflower, and asparagus)
- Milk products
- Legumes (like lentils and chickpeas)
Dietary recommendations may sometimes differ based on subtype. For example, foods and drinks with a lot of caffeine can have a laxative-like effect in some people. This means it may cause or worsen diarrhea. If you have IBS-D or IBS-M and your symptoms are worse after having caffeine, you may want to avoid it.
Exercise
Regular exercise may also decrease flares of IBS. One small study found that increasing moderate exercise for 12 weeks can improve IBS symptoms. This can include exercises like walking, cycling, and aerobics.
High-intensity exercise like running may cause GI upset. This could worsen symptoms of IBS-D. Modifying your diet or intensity of exercise may help.
Yoga may also decrease symptoms of IBS. And it may improve symptoms of constipation in IBS-C and IBS-M.
Medications
Medications for IBS usually focus on specific IBS symptoms that occur during flares. That’s one reason it’s useful to understand your subtype. It will help in targeting your treatment options.
For IBS subtypes with diarrhea, treatment often aims to reduce bowel irritability. Common medications may include:
- Loperamide
- Alosetron
- Rifaximin
For IBS-C, treatments to loosen and soften stool may help. Medications, like lubiprostone, are common to treat symptoms of constipation.
Probiotics are a common treatment for all IBS subtypes. They tend to improve bloating and gas associated with IBS, but not diarrhea or constipation.
Your provider can help you figure out the best treatment plan for your IBS subtype.
The bottom line
IBS is a common condition, but it’s not the same in everyone. The symptoms and subtypes can vary from person to person. And the treatments will also differ. Understanding your bowel patterns will help determine your IBS subtype. This will allow you and your provider to choose a treatment that’s right for you.
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