What Is Dietary Fiber?
Dietary fiber (fibre) is the indigestible part of plant foods that makes stool soft and thus enables smooth bowel movements, prevents constipation and reduces severity of hemorrhoids and diverticulosis. Other effects of fiber depend on the type – soluble or insoluble fiber (see below).
Dietary Fiber and Total Fiber
“Dietary fiber”, as noted on the ”Nutrition Facts Label” of commercial foods, is the original fiber present in the food. “Total fiber” consists of dietary fiber and added fiber – substances that are added to the original state of food to increase the fiber content or to change its physical properties. Pectin, for example, is added to jam to give it a gel form. In fiber content charts “total fiber” means a sum of soluble and insoluble fiber, though.
Soluble fiber (viscous fiber) partially dissolves in water and forms a gel with it. Foods rich in soluble fiber include beans and other legumes (peas, soy, lentils), oats, barley, citrus fruits (oranges, grapefruit), psyllium husk and flax seed. Substances found in soluble fiber are gum, pectin and mucilage.