Insoluble fibers, such as cellulose, hemicellulose, and lignin, do not dissolve in water. Insoluble fibers are found in foods such as wheat bran, whole grains, and vegetables. Insoluble fibers absorb water and increase the intestinal bulk, which helps the intestine function properly. Soluble fibers, such as gum and pectin, dissolve in water and are found in beans, oats, barley, and some fruits and vegetables. Soluble fibers may play a role in lowering blood cholesterol and in regulating the body's use of sugar.
Plant foods are the only source of dietary fiber.
The best sources of fiber are whole grain breads and cereals, fruits and vegetables, and dried beans and peas. These foods provide both soluble and insoluble fibers. Dietary fiber has important benefits in nutrition and health. Dietary fiber has preventive health benefits for many conditions, including diverticular disease, colon cancer, heart disease, and diabetes. Digestive System Dietary fiber has health benefits through its effect on the digestive system.