Causes

The causes of Crohn's disease are unknown, but researchers have several ideas as to what the culprit may be. Inflammation, the signature of Crohn's disease, appears to be an immune response from the body against a real or perceived threat.

This may be caused by the intrusion of an unknown bacteria or virus or the body’s misconception that there’s an infection or intruder when there isn't. The immune system may even be interpreting healthy bacteria or food as a danger and attempting to remove the problem.

Genetics

Charles T. Richardson, M.D., a gastroenterologist with Baylor University Medical Center in Dallas, Texas explains, “Crohn's disease is thought to occur because of an altered inflammatory response to bacteria. It is thought that the disease occurs in genetically susceptible patients. Genetic studies have shown the importance of interactions between patients and bacteria in the causation of Crohn’s Disease.”

Hereditary and environmental factors may also contribute to the disease, though researchers don’t believe Crohn's disease can be transmitted from one person to another. Recently, genes that may have something to do with Crohn's disease have been identified. People with a close relative—a parent or a sibling—who has the disease are more likely to have it themselves.

Though it can be present in any population, certain ethnic groups are more likely to have the disease. It’s more prevalent in Caucasians, particularly those who have eastern European Jewish ancestry. 

Crohn's is also likely to appear in urban populations of developed nations, prompting experts to suspect that environmental factors like pollution and diet play  a role. 

Diet

Diet isn’t believed to cause Crohn's, but it is thought to aggravate symptoms in some cases. A person with the disease may have to limit their intake of dairy products, which can worsen diarrhea, flatulence, and pain. Food containing fiber or fats can also worsen diarrhea, according to Mayo Clinic. Fiber, though an important part of a healthy diet, can act as a laxative and cause gas.

If Crohn’s is affecting the intestine's function, it might not be able to process fats, according to Mayo Clinic. Instead, fats pass through the digestive tract. If Crohn's disease requires a change in diet, it may also mean finding alternative ways to get necessary nutrition. As with any medical condition, consult your doctor before making dietary changes. It may be necessary to increase your fluid intake to counter dehydration. You should also avoid or minimize caffeinated and alcoholic beverages, as they can make dehydration worse.

Stress and Smoking

Like food, stress doesn’t cause Crohn's disease, but it can make symptoms worse and should be managed. Fortunately, there are many methods of minimizing stress. Some are as simple as trying to get enough sleep and exercise, meditating, and practicing breathing exercises. 

There may also be a link between Crohn’s and smoking. People with a history of smoking tend to be more likely to have the disease and smoking also may aggravate symptoms in someone with an active bout of Crohn's.