Most nutrients are absorbed and used by your body, but fiber passes through your digestive system without being absorbed. Still, it remains an important nutrient because it provides the bulk that helps your digestive system function properly and can protect against certain serious diseases.
There are two types of fiber: soluble and insoluble. Both types help prevent constipation, and soluble fiber has been shown to reduce the risk of colon cancer, diabetes, digestive disorders, and heart disease. Foods rich in soluble fiber include oat bran, oatmeal, beans, peas, rice bran, barley, and citrus fruits. Foods high in insoluble fiber are whole-wheat breads and cereals, wheat bran, rye, whole-grain rice, cabbage, carrots, and brussels sprouts. A diet rich in whole grains, vegetables, and fruits can easily provide the recommended 25 grams of fiber each day.