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Irritable Bowel Syndrome (IBS): Symptoms, Causes, Treatment, and More

By Joanna Foley, RD

Medically Reviewed by Yasmine S. Ali, MD, MSCI, FACC, FACP

Published on July 13, 2022

IBS can be a frustrating and difficult condition to deal with for most people. Knowing more about what it is, what causes it, and how to treat it can help you manage it more effectively.

Written by
Joanna Foley, RD
Registered Dietitian
Joanna received a Bachelor of Science in Nutrition and Dietetics from California State University and has been practicing as a Registered Dietitian for 8 years. Working in a variety of settings, her career began in a hospital setting where she worked as a clinical inpatient dietitian, supporting the care and healing of acutely ill patients.
Medically Reviewed by
Yasmine S. Ali, MD, MSCI, FACC, FACP
Board-certified Cardiologist, Medical Board Member
Yasmine S. Ali, MD, MSCI, is a board-certified cardiologist, clinical lipidologist, and internist with nearly 30 years of experience in direct patient care and 25 years of experience in medical writing, editing, and reviewing.
Irritable Bowel Syndrome (IBS): Symptoms, Causes, Treatment, and More
Photo credit: iStock.com/Moyo Studio

IBS is one of the most common digestive disorders. However, it may also be one of the most complex and misunderstood. (1)

In this article, we answer what IBS is, its symptoms and causes, and ways to treat it.

What Is IBS?

IBS is an acronym that stands for irritable bowel syndrome.

IBS is a common digestive disorder in which your digestive tract doesn’t function properly, causing uncomfortable symptoms.

IBS is estimated to affect about 10%–15% of the population. It is more common in women than men, and most people with IBS are under age 50. (2)

Unlike other gastrointestinal disorders, there is typically nothing wrong with the anatomy of the gut in people with IBS.

Instead, it is the gut function that is abnormal. This means that your digestive tract might appear normal, but it isn’t working properly.

What Are IBS Symptoms?

There are many symptoms of IBS, which may vary from person to person. They may also be unpredictable and sporadic.

Examples of common symptoms of IBS include: (3)

  • Diarrhea
  • Constipation
  • Stomach cramping
  • Bloating
  • Abdominal pain
  • Changes in frequency or consistency of bowel movements

The severity of IBS symptoms can vary from person to person and day by day. Some days you may have no symptoms, while other days might be much worse. The worse days are sometimes called IBS flare-ups.

What Causes IBS?

The exact cause of IBS is not known. It may be caused by a variety of things. However, there is increasing evidence that the following may contribute to IBS: (4, 5, 6)

  • Abnormal gut motility — or how well food moves through your digestive system.
  • Having an overactive or underactive immune system.
  • Abnormal amounts of bacteria and other microorganisms, like viruses and fungi, in the gut — known as dysbiosis.
  • Having intestinal permeability — which is when small gaps form along the gut lining.

In addition, certain problems are more common in people with IBS. (7) These may also play a role in causing or exacerbating IBS:

  • Some mental disorders — like depression and anxiety.
  • Bacterial infections in the gut.
  • Small intestine bacterial overgrowth (SIBO) — which is an increase in the number of bacteria in the small intestine to abnormal levels.
  • Stressful life events — such as physical or sexual abuse.
  • Food intolerances or sensitivities.
  • Abnormalities in the gut-brain axis (GBA) — which is the way the brain communicates with the digestive system.

Research also suggests that specific genes may make some people more likely to develop IBS. (8)

Summary

There can be many causes of IBS. Things like abnormal gut motility, an overgrowth of bacteria, and an abnormal gut-brain axis may all contribute.

How Is IBS Diagnosed?

Unfortunately, there is no one specific test or procedure to diagnose IBS. Instead, the diagnosis is most often made after excluding other possible conditions.

However, symptoms must include abdominal pain or discomfort in order to meet the criteria for IBS.

Your doctor may order various tests and procedures and ask a series of questions to help with diagnosis.

They may diagnose IBS if you experience symptoms that include abdominal pain or discomfort at least once per week for the last three months, and if your symptoms first started at least six months ago. (9)

There are different types of IBS. They are classified based on stool consistency. IBS may involve predominantly diarrhea, constipation, or be a mix of both. (5)

The diagnosis may specify which type you experience, which may also impact how it is treated.

Summary

There is not one exact test for IBS. Your doctor can diagnose it by taking a history of your symptoms and ruling out other conditions.

How to Treat IBS

While there is no cure for IBS, symptoms can be managed in a variety of ways. These often involve diet and lifestyle changes, but in more serious cases, medication can also be used.

Keeping a food and symptom diary can help you identify and keep track of what works and what may be making symptoms worse for you.

Here is an overview of some of the ways to help treat IBS:

Make Dietary Changes

This can involve many things, such as:

  • Reducing gas-producing foods and beverages — like beans, cruciferous vegetables, and carbonated beverages.
  • Limiting the amount of fat you eat, specifically from fried foods or those cooked in a lot of oil or butter. This is because fat is a common trigger for some IBS symptoms. (10)
  • Avoiding or minimizing dairy products, since lactose in milk is commonly not tolerated in people with IBS. (11)
  • Reducing alcohol usage.
  • Temporarily following a low FODMAP diet, which is described in this article.
  • Avoiding or severely restricting the use of artificial sweeteners and sugar alcohols. These can alter the gut microbiome and may trigger symptoms of IBS. (12, 13)
  • Going slow with fiber. Fiber can help improve the health of your gut and manage both diarrhea and constipation. It is best to aim for 20–35 grams of fiber per day and to increase your intake slowly if you’re not currently meeting this goal. (14)

Make Lifestyle Changes

Examples include:

  • Eating smaller, more frequent meals. This can help prevent getting overly full, which may trigger bloating.
  • Being more physically active with a variety of exercises — like walking and yoga. (15)
  • Manage stress, which can be a big trigger for IBS symptoms. (16) Setting boundaries, asking for help, getting adequate rest, and prioritizing doing things you enjoy are just some ways to help keep stress levels under control.

Consider Supplements

These have all been studied and found to be potentially beneficial for people with IBS. (17, 18, 19)

Summary

A variety of diet and lifestyle changes — like limiting gas-producing foods and eating smaller meals — can help treat IBS. Being physically active and taking certain supplements can also help.

When Should You See a Doctor?

The symptoms of IBS can be similar to other, potentially more serious conditions. This is why it is important to work with your doctor to get an accurate diagnosis and not self-diagnose to rule out other conditions.

Symptoms like bloody stools and unexplained weight loss are red flags that warrant medical attention right away.

Seeing your doctor even for less severe symptoms can help uncover a possible root cause and get a proper diagnosis.

The Bottom Line

IBS can be a complicated condition. People who have IBS all experience it differently. It may have many different causes, and the way to treat it varies as well.

Some possible causes of IBS include having abnormal gut motility or having an imbalance of bacteria in your digestive tract.

Treatment options may include diet changes (like reducing gas-producing foods), lifestyle changes (like eating smaller meals), and taking certain supplements (like probiotics).

Working with a qualified and trained healthcare practitioner can help determine what action steps you should focus on and provide guidance along the way.

Symptoms of IBS can sometimes overlap with more serious conditions. This is why it’s important to see your doctor and never self-diagnose.

While IBS cannot be cured, it is possible to manage its symptoms to experience relief and a higher quality of life.

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  1. Common GI Symptoms - American College of Gastroenterology:
    https://gi.org/topics/common-gi-symptoms/
  2. IBS Facts and Statistics - About IBS:
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  3. Recognizing Symptoms - About IBS:
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  4. What Causes IBS? - About IBS:
    https://aboutibs.org/what-is-ibs/what-causes-ibs/
  5. The gut microbiome and irritable bowel syndrome - PMC:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6039952/
  6. Intestinal barrier dysfunction in irritable bowel syndrome: a systematic review - PMC:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7925957/
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  8. Genetics of irritable bowel syndrome - PMC:
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  9. Diagnosis of Irritable Bowel Syndrome | NIDDK:
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  11. Is There a Correlation Between Irritable Bowel Syndrome and Lactose Intolerance? - PMC:
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  12. Effects of Sweeteners on the Gut Microbiota: A Review of Experimental Studies and Clinical Trials - PMC:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6363527/
  13. Gastrointestinal Disturbances Associated with the Consumption of Sugar Alcohols with Special Consideration of Xylitol: Scientific Review and Instructions for Dentists and Other Health-Care Professionals - PMC:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5093271/
  14. Dietary Fiber - About IBS:
    https://aboutibs.org/treatment/ibs-diet/dietary-fiber/
  15. Yoga as a Therapy for Irritable Bowel Syndrome - PubMed:
    https://pubmed.ncbi.nlm.nih.gov/31832970/
  16. Impact of psychological stress on irritable bowel syndrome - PMC:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4202343/
  17. Probiotics — even inactive ones — may relieve IBS symptoms - Harvard Health:
    https://www.health.harvard.edu/blog/probiotics-even-inactive-ones-may-relieve-ibs-symptoms-2020062220303
  18. Dietary fiber in irritable bowel syndrome (Review) - PMC:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5548066/
  19. Peppermint Information | Mount Sinai - New York:
    https://www.mountsinai.org/health-library/herb/peppermint#:~:text=Menthol%20and%20methyl%20salicylate%2C%20the,indigestion%20and%20irritable%20bowel%20syndrome.