IBS vs. IBD: Understanding the Differences in Digestive Health

What Is Irritable Bowel Syndrome (IBS)?

Irritable bowel syndrome (IBS) can go by many different names, including nervous stomach, spastic colon, or irritable colon, and can be categorized into different types depending on your symptoms. Some people experience IBS with diarrhea (IBS-D), IBS with constipation (IBS-C), or IBS with a mix of both diarrhea and constipation (IBS-M).

Both IBS and inflammatory bowel disease (IBD) share many similarities, including abdominal cramping, pain, and diarrhea. However, one significant difference is that IBS does not increase the risk of colon cancer, while IBD does.

What Is Inflammatory Bowel Disease (IBD)?

Inflammatory bowel disease (IBD) refers to chronic inflammatory conditions affecting the gastrointestinal (GI) tract. The two main types are Crohn’s disease and ulcerative colitis (UC). Unlike IBS, IBD can cause long-term damage to the digestive system and increase colon cancer risk.

Crohn’s Disease

Crohn’s disease is a lifelong condition that can affect both the small and large intestines. It often causes abdominal cramps and diarrhea, and is most commonly diagnosed between the ages of 15 and 30. More than 500,000 Americans are currently living with Crohn’s.

Risk factors include family history of IBD, smoking, and being between the ages of 20 and 29. Complications may include bowel obstruction, abscesses, and an increased risk of colon cancer.

Ulcerative Colitis (UC)

Ulcerative colitis affects the mucosa of the colon, leading to symptoms such as abdominal cramps, diarrhea, and bloody stools. It is also most often diagnosed between the ages of 15 and 30. About 1 in 250 people in North America and Europe are living with UC.

UC increases the risk of arthritis, liver disease (cirrhosis), and colon cancer. Risk factors include family history of IBD, frequent NSAID use, a high-fat diet, Jewish heritage, and being aged 15–30 or over 60.

Nutritional Challenges with IBD

People with IBD often struggle with undernutrition due to malabsorption, nausea, abdominal pain, and diarrhea. Nutrient losses and decreased intake must be monitored closely to prevent deficiencies.

Dietary Approaches for IBS and IBD

Dietary recommendations should be individualized, as food triggers vary from person to person. A registered dietitian can help create a tailored plan that manages symptoms and prevents nutritional deficiencies.

1. _{Crohn’s disease: What it is, symptoms, causes & treatment. Cleveland Clinic. (2025, August 14). https://my.clevelandclinic.org/health/diseases/9357-crohns-disease} 

2. _{Colorectal cancer risk factors: Hereditary colorectal risk factors. Hereditary Colorectal Risk Factors | American Cancer Society. (2025, April 29). https://www.cancer.org/cancer/colon-rectal-cancer/causes-risks-prevention/risk-factors.html} 

3. _{U.S. Department of Health and Human Services. (2024, July). Definition & facts for crohn’s disease - niddk. National Institute of Diabetes and Digestive and Kidney Diseases. https://www.niddk.nih.gov/health-information/digestive-diseases/crohns-disease/definition-facts} 

4. _{What is ulcerative colitis?. Cleveland Clinic. (2025b, June 2). https://my.clevelandclinic.org/health/diseases/10351-ulcerative-colitis}