Inflammatory bowel disease
Chronic inflammatory conditions of the colon and small intestine.
Inflammatory bowel disease (IBD) refers to a set of chronic inflammatory conditions affecting the colon and small intestine. The two main types are Crohn’s disease and ulcerative colitis. Crohn’s can involve the small intestine, large intestine, mouth, esophagus, stomach, and anus, while ulcerative colitis is limited to the colon and rectum. IBD results from a mix of environmental and genetic factors that trigger immune responses and inflammation in the gut.
Symptoms for both Crohn’s and ulcerative colitis can include abdominal pain, diarrhea, rectal bleeding, severe pelvic cramps or muscle spasms, and weight loss. The most common complication outside the digestive tract is anemia. Other associated issues are arthritis, pyoderma gangrenosum, and primary sclerosing cholangitis. Links to deep vein thrombosis have also been noted. Diagnosis typically involves checking stool for inflammatory markers, followed by a colonoscopy with biopsy of abnormal tissue.
Diet is a major concern for people with IBD, though its exact impact is not well understood. Recent reviews stress the value of nutritional counseling, encouraging patients to follow evidence-based diets and monitor for objective signs of inflammation resolution. A 2022 study found that diets rich in fruits and vegetables, low in processed meats and refined carbs, and with water as the main drink were linked to fewer active symptoms, though increased fruit and vegetable intake alone didn’t reduce Crohn’s symptoms. Another 2022 review noted positive outcomes with the Mediterranean diet. Healthy dietary patterns are associated with a 79% lower risk of ulcerative colitis. High protein intake, especially from animal sources, and high sugar consumption may raise the risk of IBD and relapses.
Emerging evidence points to bile acids as key players in IBD. Patients tend to have more primary bile acids like cholic and chenodeoxycholic acid (and their conjugates), and fewer secondary bile acids such as lithocholic and deoxycholic acid.
The gut microbiota—comprising 10–100 trillion microorganisms—differs in IBD patients compared to healthy people, with more pronounced changes in Crohn’s than ulcerative colitis.
- Field
- Gastroenterology, Immunology
- Known for
- Chronic inflammatory conditions of the digestive tract, including Crohn's disease and ulcerative colitis
- Symptoms
- Abdominal pain, diarrhea, rectal bleeding, severe internal cramps/muscle spasms in the pelvis, weight loss
- Diagnosis
- Assessment of inflammatory markers in stool followed by colonoscopy with biopsy
- Genetic factor
- First gene linked to IBD was NOD2 in 2001; over 200 single nucleotide polymorphisms associated with susceptibility
Lore & Background
Inflammatory bowel disease encompasses Crohn's disease and ulcerative colitis, both of which may present with abdominal pain, diarrhea, rectal bleeding, severe internal cramps, and weight loss. Anemia is the most prevalent extraintestinal complication. Associated conditions include arthritis, pyoderma gangrenosum, and primary sclerosing cholangitis. Diagnosis is generally by assessment of inflammatory markers in stool followed by colonoscopy with biopsy of pathological lesions.
Reader's Guide
IBD arises from the interaction of environmental and genetic factors. Diet plays a role: a 2022 study found that increased intake of fruits and vegetables, reduction of processed meats and refined carbohydrates, and preference for water were associated with lower risk of active symptoms. Gluten sensitivity is common, reported in 23.6% of Crohn's and 27.3% of ulcerative colitis patients. Emerging evidence indicates bile acids are important etiological agents, with IBD patients showing increased primary bile acids and decreased secondary bile acids. The gut microbiota differs in IBD patients, with decreased beneficial bacteria like Bifidobacterium longum and Faecalibacterium prausnitzii, and increased harmful species like Bacteroides fragilis. Oxidative stress and DNA damage likely have a role, with increased 8-OHdG levels found in IBD patients. Genetic studies have identified over 200 single nucleotide polymorphisms associated with susceptibility, and the ETS2 gene directs the macrophage inflammation that drives the disease.
Did You Know?
- Anemia is the most prevalent extraintestinal complication of inflammatory bowel disease.
- Gluten sensitivity was reported in 23.6% of Crohn's disease patients and 27.3% of ulcerative colitis patients.
- The first gene linked to IBD was NOD2 in 2001.
- A 2022 study found that a diet high in fruits and vegetables and low in processed meats was associated with lower risk of active symptoms.
More in Steroid-responsive inflammatory conditions 1-24
Spotted an error? Know more?
Reader corrections go straight into our review queue. Suggest an edit · How this site is sourced