Diverticulosis is a common condition. More than half of all elderly people in the United States have it. Diverticula seem to occur when the pressure inside the colon is too high. There are several ways this pressure may become high. The main cause of high pressure appears to be too little fiber in the diet.
Fiber helps keep digested food bulky and soft as it passes through the colon.
This makes it easier for the food to move through the intestine without too much pressure. Sometimes the muscles of the large intestine simply do not work correctly. As digested food moves through the colon, muscle spasms may occur in the colon, causing increased pressure. People who have irritable bowel syndrome may have a higher risk of developing diverticulosis because of such problems with muscle spasms. Many people who have diverticulosis do not have any symptoms.