WHAT IS DIETARY FIBER?

Dietary fiber is a term for chemical substances in the cells of plants that cannot be digested by the human body. Each of the different types of dietary fiber has different effects on functions of the digestive tract, such as water absorption, and fat metabolism. Metabolism is a chemical process in the body by which food is broken down and changed to energy.

WHY CAN'T THE HUMAN BODY DIGEST DIETARY FIBER?

Dietary fiber cannot be digested by humans because they lack the necessary enzymes (proteins that help produce chemical reactions). More specifically, dietary fiber is resistant to hydrolysis. Hydrolysis is a process in which a substance is broken down by splitting its bond and adding water to it. Since dietary fiber cannot be digested, it passes through the body virtually unchanged and cannot be used as an energy source. Although humans cannot digest dietary fiber, some of it is broken down by bacteria to produce gas and acids.

WHAT ARE THE BENEFITS OF EATING FOODS WITH DIETARY FIBER?

Dietary fiber adds bulk (mass) to the diet and helps prevent disease of the intestine and the colon. The intestine is a tube shaped structure that is part of the digestive tract. It is divided into the small and large intestine. Fiber also decreases the amount of pressure in the colon. The colon is the major part of the large intestine. Dietary fiber also helps prevent constipation (difficulty pooping) because it helps move the intestine, which, in turn, helps move poop out of the body. Dietary fiber also helps prevent constipation by adding bulk to the feces by removing water from it. By making the poop larger, dietary fiber helps it move through the intestines more easily. To keep the bowel healthy, a person should eat several servings of dietary fiber each day.

WHAT FOODS ARE GOOD SOURCES OF DIETARY FIBER?

Dietary fiber can be found in leafy green vegetables, such as cabbage, lettuce, spinach, celery, salads, carrots, turnips, and potatoes. It can also be found in raw and cooked fruits, cereals, peas, beans, and whole-grain foods. Over the counter products are available that provide an extra source of fiber to the diet. Metamucil, Citrucel, and FiberCon are examples of such products.

WHAT IS DIETARY FIBER MADE OF?

The main substances that make up dietary fiber are gums and pectin (thick, jelly-like substances found in fruits and vegetables), as well as lignin, cellulose, and hemicellulose. The last three substances form the main structure of plant cell walls. These five substances provide a plant with a structure that is partially rigid, yet stable.

WHAT ELSE IS DIETARY FIBER KNOWN AS?

Dietary fiber is also known as fiber, bulk, and roughage.