What causes Diverticular Disease ?
Scientists are not certain what causes diverticulosis and diverticular disease. For more than 50 years, the most widely accepted theory was that a low-fiber diet led to diverticulosis and diverticular disease. Diverticulosis and diverticular disease were first noticed in the United States in the early 1900s, around the time processed foods were introduced into the American diet. Consumption of processed foods greatly reduced Americans fiber intake. Diverticulosis and diverticular disease are common in Western and industrialized countriesparticularly the United States, England, and Australiawhere low-fiber diets are common. The condition is rare in Asia and Africa, where most people eat high-fiber diets.1 Two large studies also indicate that a low-fiber diet may increase the chance of developing diverticular disease.2
                
However, a recent study found that a low-fiber diet was not associated with diverticulosis and that a high-fiber diet and more frequent bowel movements may be linked to an increased rather than decreased chance of diverticula.3
                
Other studies have focused on the role of decreased levels of the neurotransmitter serotonin in causing decreased relaxation and increased spasms of the colon muscle. A neurotransmitter is a chemical that helps brain cells communicate with nerve cells. However, more studies are needed in this area.
                
Studies have also found links between diverticular disease and obesity, lack of exercise, smoking, and certain medications including nonsteroidal anti-inflammatory drugs, such as aspirin, and steroids.3
                
Scientists agree that with diverticulitis, inflammation may begin when bacteria or stool get caught in a diverticulum. In the colon, inflammation also may be caused by a decrease in healthy bacteria and an increase in disease-causing bacteria. This change in the bacteria may permit chronic inflammation to develop in the colon.
                

                
What is fiber?   Fiber is a substance in foods that comes from plants. Fiber helps soften stool so it moves smoothly through the colon and is easier to pass. Soluble fiber dissolves in water and is found in beans, fruit, and oat products. Insoluble fiber does not dissolve in water and is found in whole-grain products and vegetables. Both kinds of fiber help prevent constipation.   Constipation is a condition in which an adult has fewer than three bowel movements a week or has bowel movements with stools that are hard, dry, and small, making them painful or difficult to pass.   High-fiber foods also have many benefits in preventing and controlling chronic diseases, such as cardiovascular disease, obesity, diabetes, and cancer.2