Dietary Fiber: Soluble Vs. Non-soluble

The word "fiber" is often thrown around and attached to claims that it is an essential part of any diet. While you can take this claim at face value, you may be interested to know what fiber actually is and how it helps your body stay healthy. The general definition for fiber is the portion of a plant food that your body cannot digest. Dietary fiber belongs to the carbohydrate group of nutrients and is divided into two classes based on how your body handles it.

Soluble Fiber

Soluble fiber attracts and dissolves in water in your body. Because of this property, soluble fiber turns into a gel-like material during digestion. This gel-like material slows down the digestion process, which provides a number of health benefits. Soluble fiber is highly regarded for its role in lowering LDL cholesterol levels, which in turn can decrease your risk for heart disease and heart attack. Soluble fibers also slow the rate at which fats and carbohydrates are digested. The decreased digestion rate helps lower the amount of fat in your blood after a meal and can improve your sensitivity to insulin.

Insoluble Fiber

Insoluble fiber attracts water but cannot dissolve in it. Insoluble fiber moves through your digestive system in its full form, which allows it to provide its specific health benefits. When insoluble fiber is present in your digestive tract, it pulls water into the intestines from other areas of your body. This water mixes with waste products, adding bulk and softness to your stool and making it easier to pass. When stools are easier to pass, you do not have to strain as much during a bowel movement, which reduces the pressure in your colon and reduces your risk of developing hemorrhoids or pouches in the colon called "diverticula."

Other Benefits

Both types of fiber are considered low-density foods. This means they are high in volume, but low in calories. This winning combination helps to fill up your stomach quickly, without contributing excess amounts of calories that can cause weight gain. Because of this, high-fiber foods are linked to weight maintenance and weight loss. "Nutrition and You" by Joan Salge Blake, notes that obese men and women tend to have lower amounts of fiber-rich foods in their diet than people of normal or lower weight.

Food Sources

Most foods contain a combination of both types of fiber, although some foods are particularly high in one or the other type of fiber. Foods that are particularly high in soluble fiber include oat bran, oatmeal, rice bran, barley, citrus fruits, beans, peas, apples and strawberries. According to the American Heart Association, oats have the highest proportion of soluble fiber compared to any other grain. Foods that contain mostly insoluble fiber include whole wheat bread, wheat cereals, bran, rice, barley, beets, carrots, cabbage, cauliflower, apple skin and Brussels sprouts.