Crohn's disease is an inflammatory condition that affects the gastrointestinal tract. It is a chronic, or long-term, condition and it is a form of inflammatory bowel disease.
Crohn's disease most commonly affects the colon and the end of the small intestine, known as the ileum, but it can affect any part of the gastrointestinal tract.
A person with Crohn's disease may experience flare-ups and remissions. They may have no symptoms for a long time and then, one day, they return.
The exact cause of Crohn's disease is unclear, but there is a link between a person's diet and the incidence of flare-ups.
The intestinal system of a person with Crohn's disease reacts to food and beneficial substances as if they were unwanted pathogens. This leads to an accumulation of white blood cells in the digestive system, resulting in chronic inflammation.
One complication of Crohn's disease is the risk of poor nutrient absorption.
Normally, the small intestine absorbs most of the nutrients from food. If the small intestine treats food as a threat, little food is absorbed. A person with Crohn's disease may become deficient in nutrients and this can be dangerous if left unchecked.
A person with Crohn's disease can have regular blood tests to ensure that they are properly nourished. If not, they can take supplements to ensure they are taking in what they need in terms of nutrients.
Impact of diet
The food a person eats and incidences of Crohn's disease are closely linked. It is not that particular foods cause Crohn's disease, but some foods may make existing symptoms worse or cause the disease to flare up.
The triggers vary between individuals, but foods that may cause symptoms include:
- Overly spicy foods
- Caffeinated drinks like coffee, tea, and soda
- Dairy products if lactose intolerant
- Wheat, barley, rye, and oats if gluten intolerant
- Fried foods
- High-fat foods
- High-sugar foods
A person with Crohn's disease should keep track of their entire dietary intake by keeping a food journal. Knowing exactly what has been eaten during an episode of Crohn's can help identify the food or drinks responsible.
In a review posted to Nutrition in Clinical Practice, researchers outline the growing evidence surrounding diet and inflammatory bowel diseases such as Crohn's. The review suggests that making changes to the diet can be very beneficial.
Dietary fatty acids are an important part of a balanced diet, but the benefit depends on the type of fat. Omega-3 fats, for example, can reduce inflammation in the body, while omega-6 fats tend to increase it.
One observational study suggests that a high intake of omega-6 fats, such as linoleic acid, is associated with a higher risk of inflammatory bowel disease (IBD).
Foods high in omega-6 fats such as linoleic acid include:
- Red meat
An increased intake of omega-3 fats, such as docosahexaenoic acid (DHA), showed a reduced risk of IBD. Foods high in omega-3s include:
- Cold water fish
Some people say that a simple dietary supplement of omega-3 fish oils can reduce outbreaks. Unfortunately, there is not enough scientific evidence to support this claim, but a person who takes omega-3 supplements is unlikely to make their symptoms worse. Anyone taking supplements should remember to note them in their food journal.
Fiber also has an impact on Crohn's disease. Humans are unable to digest fiber; instead, the bacteria living in the intestines eat it.
One theory suggests that a person who has a fiber-rich diet could increase the diversity of bacteria in their intestines and that these extra bacteria may reduce the inflammation linked to Crohn's disease.
Many people with Crohn's find that a high-fiber diet brings relief from symptoms, but unfortunately there is little clinical evidence to back this up.
The low-residue diet
The low-residue diet is based on the idea that reducing the amount of "residue" the food leaves behind after digestion will reduce symptoms of IBD.
"Residue" refers to substances such as fiber, which are not digested and increase the amount of stool in each bowel movement. The low-residue diet also restricts certain dairy foods and meat products.
As the low-residue diet reduces the amount of stool that passes through the inflamed areas of the digestive system, advocates believe this may reduce the symptoms. However, there is little recent clinical evidence that reducing dietary fiber will help with Crohn's symptoms unless it is via a short-term liquid diet.
A person with celiac disease has a severe autoimmune reaction to gluten. Researchers note that people who have Crohn's but who do not have celiac disease are more likely to experience adverse reactions to gluten. This suggests that a gluten-free diet may be useful for people who have Crohn's disease.
Microflora modulation for Crohn's disease
Scientists are currently investigating the possibility that unhealthy gut bacteria might play a key role in inflammatory diseases such as Crohn's.
Although scientific confirmation is lacking, a recent review published by the World Journal of Gastroenterology suggests that adjusting intestinal flora can relieve symptoms of many intestinal diseases.
Modifying the flora in the intestines can be achieved in different ways, such as introducing probiotics, prebiotics, antibiotics, and more fiber into the diet. The report suggested that probiotics were the least effective, but they still showed signs of improving symptoms such as diarrhea. People that have reactions to any of these substances should log them in their dietary journal
Another treatment option is a fecal microbe transplant, which involves replacing the bad bacteria with healthy fecal bacteria from a donor.
Other dietary considerations for Crohn's disease
After keeping a food diary during a flare-up, many people change their dietary patterns.
For example, people with Crohn's disease who notice their symptoms get worse after eating meat products may switch to a vegetarian diet to find relief. If dairy products show a pattern of symptoms, eliminating dairy might be advisable.
While people with Crohn's disease will have some symptoms in common, the condition is very individual, and treatment should be on one-to-one basis.
The fact that Crohn's disease appears differently from person to person may explain why so many studies have inconclusive results.
If a person keeps an accurate food journal and works closely with their doctor, it may be possible to establish what causes their specific symptoms.
People with Crohn's disease may find that by understanding what triggers and relieves a flare up, they can better control their symptoms and improve their quality of life.
Because Crohn's disease affects many parts of the gastrointestinal tract, symptoms will vary from person to person. The most common symptoms of Crohn's disease are:
- Persistent constipation, which can lead to bowel blockage
- Persistent diarrhea
- Stomach cramps and pains
- Urgent need for bowel movement
- A sensation of "unfinished" bowel movements
- Rectal bleeding
Possible symptoms of IBD, including Crohn's disease, are:
In younger children, Crohn's disease may delay growth and development. In severe cases, it may cause tears or fissures in the lining of the anus, causing pain and bleeding when emptying the bowels.