Diverticulitis is a condition in which abnormal pouches (diverticula) that form in the colon become inflamed. While the causes of the condition are unproven, most doctors believe it is linked to a low-fiber diet. Researchers are also unsure what causes the infection that takes place during an attack. It is believed that the infections occur when stool or bacteria are caught in the diverticula.
Many people have small pouches in their colons that bulge outward through weak spots, like an inner tube that pokes through weak places in a tire. Each pouch is called a diverticulum. Pouches (plural) are called diverticula. The condition of having diverticula is called diverticulosis. About 10 percent of Americans over the age of 40 have diverticulosis. The condition becomes more common as people age. About half of all people over the age of 60 have diverticulosis.
When the pouches become infected or inflamed, the condition is called diverticulitis. This happens in 10 percent to 25 percent of people with diverticulosis. Diverticulosis and diverticulitis are also called diverticular disease.
Although not proven, the dominant theory is that a low-fiber diet is the main cause of diverticulitis. Diverticulitis was first noticed in the United States in the early 1900s. At about the same time, processed foods were introduced into the American diet. Many processed foods contain refined, low-fiber flour. Unlike whole-wheat flour, refined flour has no wheat bran.
Diverticulitis is common in developed or industrialized countries -- particularly the United States, England, and Australia -- where low-fiber diets are common. The disease is rare in countries of Asia and Africa, where people eat high-fiber vegetable diets.
Fiber is the part of fruits, vegetables, and grains that the body cannot digest. Some fiber dissolves easily in water (soluble fiber). It takes on a soft, jelly-like texture in the intestines. Some fiber passes almost unchanged through the intestines (insoluble fiber). Both kinds of fiber help make stools soft and easy to pass. Fiber also prevents constipation.
Constipation makes the muscles strain to move stool that is too hard. It is the main cause of increased pressure in the colon. This excess pressure might cause the weak spots in the colon to bulge out and become diverticula.
Diverticulitis occurs when diverticula become infected or inflamed. Doctors are not certain what causes the infection. It may begin when stool or bacteria are caught in the diverticula. An attack of diverticulitis can develop suddenly and without warning.