Irritable Bowel Syndrome vs. Inflammatory Bowel Disease

Good gut health is often at the top of everyone’s priority list. Simply put, when your gut feels good, you feel good. On the flip side, gastrointestinal issues can leave you feeling uncomfortable — not to mention unmotivated. 

Irritable Bowel Syndrome and Inflammatory Bowel Disease are two common gastrointestinal issues that can disrupt digestive health. Let’s take a closer look at these gut conditions, how they overlap, and their key differences. 

What Is the Digestive System?

In simple terms, the digestive system is a complex network of organs and tissues that work together to break down and absorb vital nutrients your body needs. As we all know, a happy digestive system is essential for maintaining a high quality of life and health. 

The gastrointestinal tract, or GI tract, is at the heart of the digestive system. It literally goes from your top to your bottom. This digestive tract includes a series of hollow organs. 

Starting at the mouth and going down, these hollow organs include the esophagus, stomach, small intestine, large intestine and anus. The solid organs of the digestive tract include the liver, pancreas and gallbladder.

Along with these organs, bacteria (gut flora) are also an important part of digestion. In addition to helping break down food for nutrients, the gut microbiome is also crucial for the immune system.

A Look at Digestive Health

The digestive system’s primary role is to help convert the food you eat into nutrients or energy for the body. These nutrients include proteins, fats, carbohydrates, vitamins and minerals. 

It starts with the food and ends — well, at the end. Bowel movements (stool) are simply a waste product of the digestive process. 

Good health and wellbeing include caring for your gut. The digestive system and gut health can be disrupted in many ways. For example, stress and poor nutrition can wreak havoc on your digestive system over time. 

According to the National Institutes of Health, digestive diseases affect between 60 to 70 million people in the United States. These can range from serious conditions like Crohn’s disease and ulcerative colitis to short-term conditions like constipation and gallstones. 

The most common functional gastrointestinal conditions are Irritable Bowel Syndrome and Inflammatory Bowel Disease. Now it’s time to explore these two digestive conditions in more depth. 

What Is Irritable Bowel Syndrome?

Irritable Bowel Syndrome (IBS) is a chronic disorder of the body’s digestive tract. This functional gastrointestinal (GI) disorder is marked by abdominal discomfort and altered bowel habits. Functional GI disorders are disorders of gut-brain interaction. 

The term “functional” simply refers to an impairment in the body’s normal activities, such as digestion. The three primary features of functional GI disorders are motility, sensation and brain-gut dysfunction.

IBS is primarily a motility issue. This refers to the speed of the muscle contractions within the intestinal tract. IBS also goes by other names, including ‘irritable colon’ or ‘spastic colon.’

Causes and Symptoms of IBS

The exact cause of IBS is still up for debate within the healthcare community. Numerous risk factors could contribute to the prevalence of IBS, including things like family history and medical history. 

However, researchers agree that it is an issue of the brain-gut connection. For example, for some people with IBS, food may move too slowly (or too quickly) through the GI tract, causing issues with bowel movements. Potential causes of IBS may also include stress and food intolerances (e.g. gluten sensitivity). 

According to researchers, other causes of IBS may also include visceral hypersensitivity with the GI tract and dysmotility, which involve issues with muscle contraction movement within the GI tract.

The most common symptoms of IBS include abdominal pain and discomfort. These are typically related to bowel movements, particularly changes in bowel movements like constipation or diarrhea. 

Other symptoms include:

  • Bloating and cramping feeling 
  • Changes in bowel movements (harder or looser)
  • Excess flatulence (gas)
  • Whitish mucus in the stool

Diagnosing IBS

IBS can be diagnosed by a healthcare provider. A physical examination and a medical history are typically the first steps in diagnosing IBS. You can also expect many questions about your IBS flare-ups. 

In some cases, further tests may be necessary to confirm. Furthermore, gastroenterology professionals may run additional tests, such as a colonoscopy or endoscopy, to confirm or rule out other conditions. Gastroenterologists specialize in diagnosing and treating digestive issues. 

The three main IBS diagnoses include:

  • IBS with constipation (IBS-C)
  • IBS with diarrhea (IBS-D)
  • IBS-mixed (IBS-M)

What Is Inflammatory Bowel Disease?

Inflammatory Bowel Disease (IBD) is a group of conditions that contribute to chronic inflammation within the GI tract, particularly the intestines. The two main types of IBD include Crohn’s disease and ulcerative colitis. 

  • Crohn’s disease is a long-term digestive condition that causes intense inflammation within the GI tract. It can occur in any part of the GI tract, from the mouth to the anus. 
  • Ulcerative colitis is another chronic, life-long condition that involves recurring bouts of inflammation in the mucosal layers of the colon. It typically occurs in the rectum.

Causes and Symptoms of IBD

The exact cause of IBD is not conclusive. However, many healthcare researchers believe it could be a combination of genetics, immune system response and environmental factors.

IBD can cause common digestive symptoms such as diarrhea, constipation, bloating, cramping, and more. However, additional symptoms can arise depending on the form of IBD. These symptoms may include unexplained weight loss, blood in the stool and more. 

IBD can also contribute to numerous digestive complications, including:

  • Anemia, or low levels of red blood cells
  • Higher risk of developing colon cancer 
  • Anal fistulas
  • Rectal bleeding

Diagnosing IBD

Like IBS, a physical exam and medical history is required to diagnose IBD. However, for an accurate diagnosis of IBD may require additional diagnostic testing, such as colonoscopy, endoscopic ultrasound (EUS), and more.

What Are the Main Differences Between IBS and IBD?

There is a lot of overlap between IBS and IBD, especially in symptoms. For example, they share common symptoms, including abdominal pain, bloating, diarrhea, and bowel movement changes. 

However, IBD can have more serious symptoms, including black, bloody stools, weight loss, fever and more. Even with their overlapping symptoms, these two digestive conditions still differ in many ways. 

Differences in Pain Location

While pain is a symptom of both conditions, the location of the pain often varies between each condition. For example, IBS patients often describe pain and discomfort as being widespread throughout the abdomen. 

In the case of IBD, pain is more localized. Pain in the lower right side of the abdomen is common in Crohn’s disease, while pain concentrated on the left side is more indicative of ulcerative colitis. 

The Prevalence of IBS and IBD

Another difference comes in the prevalence of each condition. IBS is extremely common, affecting 25 to 45 million people in the United States. It also tends to be more prevalent among younger people. IBD affects around 3 million adults in the United States, only 1.3% of the population. 

Differences in Diagnosis

As mentioned above, diagnosis generally starts with a physical examination and medical history. This applies to both conditions. 

However, diagnosing IBD can go beyond that in many cases. Often, an IBD diagnosis will also require additional testing, including blood and stool tests, x-ray imaging, MRIs, and even biopsy. 

Differences in Treatments

Since there is no cure for these conditions, treatment typically focuses on managing and reducing the severity of symptoms. Lifestyle changes are often required for both IBS and IBD. This includes dietary changes. 

For example, limiting symptom-triggering foods is at the top of the list. This varies from person to person, depending on food intolerances and sensitivities. However, a FODMAP diet is very common among those dealing with digestive issues. 

IBS treatments and supplements typically aim at IBS symptom relief. This includes relief from abdominal discomfort, digestive spasms, and excess flatulence. In addition to diet and supplements, probiotics can also be helpful to help boost healthy gut bacteria. 

The goal of IBD treatments is to reduce symptoms of inflammation. This includes the use of anti-inflammatory drugs, such as corticosteroids or aminosalicylates. Antibiotics are also commonly prescribed to help when infections are present. 

For IBD, other treatments can include the use of biologics and surgery. In fact, many people with IBD conditions like Crohn’s disease end up having surgery to repair GI tract damage. 

The Bottom Line

IBS and IBD are two digestive conditions with similar symptoms. While IBS can certainly disrupt your life, it is typically manageable with the right plan. 

The right management plan can help reduce any long-term effects. However, IBD is a lifelong condition with symptoms that come and go. Management of IBD tends to be much more intensive. 


Digestive Diseases Statistics for the United States | NIDDK

Irritable bowel syndrome and inflammatory bowel disease overlap syndrome: pieces of the puzzle are falling into place | PMC

IBS Facts and Statistics | About IBS

Prevalence of IBD | CDC