Why are Crohn's disease and colitis such mysteries?

Kathleen Blanchard's picture
What is the mystery behind what causes IBD?

Crohn's disease and ulcerative colitis are somewhat of a medical mystery. How the diseases develop just isn't known. There are treatments that can treat symptoms, but without knowing the cause, neither could be cured. For those dealing with IBD, everyday is an opportunity for new hope.

Crohn's and colitis are the same, but different

Both forms of IBD are similar, but Crohn's disease affects the entire gastrointestinal tract to form ulcers. Ulcerative colitis affects only the intestines. Both of the diseases were discovered in 1932, but despite all the years of research, there are still many unanswered questions.

What causes IBD?

Like other autoimmune and mysterious diseases (multiple sclerosis, rheumatoid arthritis, Parkinson's disease), scientist just aren't sure. The most likely answer is that Crohn's and colitis is caused by a combination of factors that include genes, environmental triggers and the way a person's immune system behaves.

Scientists know IBD develops when "good" bacteria in the gut is destroyed by a person's own immune system, which leads to inflammation and damage to the intestine that in turn causes cramping, bloating, abdominal pain, diarrhea and other bowel habit changes. The result can be scarring or fibrosis of the intestines that causes narrowing - one of the biggest reasons Crohn's disease often leads to surgery.

Researchers have found genes that overlap between Crohn's disease and ulcerative colitis that cause the immune system to attack good bacteria in the gut. But the question remains, what triggers such a response?


IBD on the rise, but why?

Even though IBD was discovered in 1932, it is suddenly on the rise. Some research has linked the Western diet to increased risk of developing inflammatory bowel disease. A 2011 study showed an association between consuming too many omega-6 fatty acids in the form of red meat and polyunsaturated fatty acids (PUFAs) and higher risk of Crohn's and colitis.

The finding, published in the American Journal of Gastroenterology, found high fat intake in the form of PUFAs, omega-6 fatty acids, and meat raised the risk, while consuming more fiber and fruits was linked to a lower chance of the disease. The finding was a study review that again, failed to show cause, but since then the link has grown stronger.

Newer evidence shows Crohn's and colitis are becoming more common in Japan. The suspected culprit is inflammation from a Western diet - again.

See: Is there an anti-inflammatory diet that works for Crohn's disease?

The take home message is we have to wait to know how to prevent IBD. But understanding what might contribute to Crohn's and ulcerative colitis should provide valuable clues about how to better manage the disease that will take time and patience. There are many mysteries that remain about IBD. The strongest environmental link to how Crohn's and colitis develop, or at least are triggered, is that it is from a dance that occurs between eating a Western diet and genetic predisposition.

"Dietary intake and risk of developing inflammatory bowel disease: a systematic review of the literature."
Hou JK, Abraham B, El-Serag H.

"Crohn's Disease-Associated Adherent-Invasive Escherichia coli Adhesion Is Enhanced by Exposure to the Ubiquitous Dietary Polysaccharide Maltodextrin"
Kourtney P. Nickerson, Christine McDonald
December 12, 2012

Canadian Digestive Health Foundation
Understanding FODMAPs