Although not proven, the main cause of diverticular disease is believed to be a low-fiber diet. Fiber is the part of fruits, vegetables, and grains that the body cannot digest.
- Soluble fiber dissolves easily in water and takes on a soft, jelly-like texture in the intestines.
- Insoluble fiber passes almost unchanged through the intestines.
Both kinds of fiber help make stools soft and easy to pass, which helps to prevent constipation.
Constipation is the main cause of increased pressure in the colon, making the muscles strain to move stool that is too hard. The excess pressure caused by the straining makes the weak spots in the colon bulge out, forming diverticula.
Physicians do not know what causes the infection that causes diverticulitis, but believe it may begin when stool or bacteria are caught in the diverticula.