Dietary fiber plays several important roles in the human body, including regulating bowel movements, maintaining bowel health, lowering cholesterol levels and controlling blood sugar levels. The Mayo Clinic lists preventing colon diseases, promoting heart health and maintaining a healthy weight as additional benefits of adequate dietary fiber.
Dietary fiber consists of all the parts of plants that are unable to break down during digestion. WebMD states that dietary fiber is split into two categories: insoluble and soluble. Insoluble fiber does not dissolve in water, while soluble fiber does. Both types of fiber are considered important to a healthy diet.
Soluble fiber forms a gel-like material when it come into contact with water in the digestive tract. WebMD says that this slows down digestion and makes a person feel full, an important part of maintaining a healthy weight. Soluble fiber controls the rate at which the stomach empties, keeping blood sugar levels in check. It also inhibits the absorption of dietary cholesterol and helps keep LDL cholesterol levels down.
The laxative effect of insoluble fiber is also important. Since insoluble fiber does not dissolve into water, it remains mostly intact in the digestive tract. According to WebMD, soluble fiber works in the digestive tract by adding bulk to waste and helping it slide through the digestive tract more quickly, preventing constipation.