Introduction
Inflammatory bowel disease (IBD) is a chronic immune-mediated disease of the gastrointestinal tract. It is progressive in nature and worsens when something that irritates the bowel is consumed. The cause is still unclear, though genetic, environmental, and host-related factors are thought to have an association. This article deals with the role of fiber in flaring up an irritable bowel.
What Is Dietary Fiber?
The plant-derived portion of food that is not easily digested by the human body is called fiber. It is mainly found in fruits, vegetables, whole grains, and legumes. It is known for its ability to prevent constipation. The other health benefits include managing body weight and lowering the risk of diabetes, heart disease, and some types of cancer. It is mainly a type of carbohydrate and helps in digestion.
What Are the Types of Dietary Fiber?
Dietary fibers are of two types, soluble and insoluble. Soluble fibers are soluble in water and are found in fruits and vegetables. Being soluble, they form viscous solutions and are highly fermented. Whole grains (like oats, barley, and wheat), legumes like lentils, split peas, guar seeds, pinto beans, black beans, red beans, chickpeas, and lima beans), some fruits and vegetables (apples, oranges, and carrots) and seeds (linseed and psyllium seeds) are rich sources of soluble fiber. They help to reduce blood lipid levels, blood pressure, inflammation, risk of cardiovascular disease (CVD), and intestinal transit time. They are also found to improve blood sugar levels, weight control, and immune function.
Insoluble fibers, on the other hand, do not dissolve in water and decrease the time to pass through the gut. They are less fermentable by the gut microbiome. This is usually found in plant cells and is the building block of the cell wall. It is found in wholemeal flour, wheat bran, brown rice, nuts, beans, vegetables (like cabbage, celery, cauliflower, and Brussels sprouts), and fruits. They cause a feeling of fullness and act as a laxative (a substance that increases bowel movements and treats constipation).
Which Foods Are High in Dietary Fiber?
Many grains, fruits, and vegetables contain fiber. Beans and whole wheat products are the most commonly used fiber-rich foods. Other foods that are high in fiber include avocados, peas, broccoli, apples, oranges, and almonds. About 25 to 34 grams per day is the daily dietary fiber requirement in an adult. Increased fiber intake reduces the risk of cardiovascular disease, stroke, diabetes, and colon cancer, according to experts.
What Is Inflammatory Bowel Disease?
Inflammatory bowel disease is a chronic condition of the gastrointestinal tract that can be painful. It can alter the quality of life of the affected individuals. Because of the severe inflammation it is associated with, the condition has a high risk of morbidity, disability, and the risk of complications like abdominal abscesses, fistulae, strictures, and subsequent bowel obstruction, and an increased risk of gastrointestinal (GI) cancer.
What Are the Symptoms of Inflammatory Bowel Disease?
According to the Centers for Disease Control and Prevention (CDC), IBD is an umbrella term for two conditions of the digestive tract, Crohn’s disease and ulcerative colitis. Both these conditions show an inflammation of the digestive tract, and destroy the gastrointestinal system. The common symptoms of IBD include:
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Abdominal pain.
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Frequent diarrhea.
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Blood in stools.
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Bleeding at the rectum.
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Weight loss.
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Tiredness.
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Loss of appetite.
How Is Inflammatory Bowel Disease and Dietary Fiber Linked?
Fibers in diet are not digested by the body. They remain in the gut and are fermented by the bacteria and fungi in the gut, commonly called the gut microbiome. One research by the Department of Internal Medicine at the University of Manitoba considers that the gut microbiome gets altered due to this fermentation. It is also unclear as to what happens after this fermentation. It is also pointed out that more fiber that remains undigested is common among those who have IBD. However, the matter is still controversial and requires further research.
In the previous literature on the topic, people with IBD were advised to minimize the use of dietary fibers or stay away from them. However, recent ones advocate the use of fiber, especially soluble fibers in the diet. However, the amount required by each individual may differ.
A study by the Department of Pediatrics at the University of Alberta found that the individuals who did not ferment the fiber had inflammatory reactions later. Hence, it is important what type of fiber is consumed. While consuming fiber can be beneficial for gut health, some types of fiber can worsen IBD, as these people may lack the microbiome to digest it.
A diet that includes fiber, when coupled with vitamin D and adequate amounts of citrus fruits has a protective role in irritable bowel syndrome. Studies show that increased consumption of fiber and fruits in the diet showed an improvement in a majority of the people suffering from Cohn’s disease. On the other hand, those with ulcerative colitis were relieved by a diet rich in vegetables. However, people with IBD should closely monitor their diet for any change in symptoms.
FODMAPs, or fermentable carbohydrates, have an important role in the IBD diet. They are oligosaccharides, disaccharides, monosaccharides, and fermentable polyols. They have an osmotic and fermentative effect on the digestive tract. They absorb water in the intestinal lumen and remain partially or completely undigested. Hence, it is recommended that people with IBD (especially those who have symptoms like frequent abdominal pain, meteorism or the accumulation of gas in the digestive system, bloating, diarrhea, or constipation) should follow a low-FODMAP diet.
What Are the Complications of IBD?
If IBD is left untreated, it increases the risk of colon cancer. It can also be associated with intestinal blockages or ruptures. Severe cases might even show symptoms that are not related to the gastrointestinal system, like rashes, arthritis, and eye inflammation. Those who have less absorption may be malnourished and show fatigue and weight loss. It can lead to anemia as the food does not get absorbed into the body properly. Kidney stones, liver diseases like cirrhosis, and primary sclerosing cholangitis (inflammation of the bile ducts) can also be seen.
Conclusion
Diet plays an important role in managing IBD. However, there is no component in the diet that has shown a clear correlation with the condition. Some types of dietary fiber have been shown to worsen the condition, while others have improved it. Hence, cautious use is advisable. Patients should monitor their diet for the symptoms observed and decide accordingly whether to include or exclude it from their diet.
