Getting to the core of Fiber

Fiber is the part of fruits, vegetables, and grains that is neither digested nor absorbed. Fiber helps keep your intestines working comfortably and helps prevent many diseases. Fiber comes in two forms, soluble and insoluble. Each acts differently in the intestines and benefits the body in different ways. Soluble fiber acts like a sponge; insoluble fiber acts like a broom.

Soluble fiber. Found in dried beans and peas, oat bran, rice bran, barley, and fruit pectin (the substance used to thicken jams and jellies). Soluble fiber absorbs water in the intestines, mixes the food into a gel, and thereby slows the rate of glucose digestion and consequent absorption in the bloodstream.

Insoluble fiber. This is the stringy stuff that holds plants together. It's called "insoluble" because it doesn't dissolve in water. It can be found mainly in plant leaves, peels, skins, and the coverings of whole grains (e.g., wheat bran). Like a disposable diaper, insoluble fiber can absorb many times its own weight in water. This water adds bulk and softness to the stools and keeps them moving along more comfortably. Think of eating fiber like brushing your teeth - it cleans out your intestines daily.