Tip:  Because some of the benefits of a high-fiber diet may come from other components present in these foods, fiber is best obtained from foods rather than supplements.

A well-balanced diet is important for healthy living, and fiber has a key role to play. While it's often associated with proper bowel function, fiber can also be beneficial in preventing certain cancers as well as reducing the risk of heart disease and stroke. But what exactly is fiber, and in what foods can it be found?

There are two types of fiber: soluble and insoluble. Insoluble fiber is the indigestible part of food — the bran in grain, the pulp of fruit, and the skin of vegetables. Soluble fiber can be only partially digested by the body and can be found in foods such as apples, oats, dried beans, and green vegetables.

The Many Benefits of Fiber

Eating a variety of fiber-containing foods is important for proper bowel function, can reduce the risk of chronic constipation, diverticular disease, and hemorrhoids, and may lower the risk for heart disease and some cancers.

Insoluble fiber helps move food through the large intestine and out of the body. It can increase the bulk of the stool and facilitate excretion from the body, keeping the lower digestive tract running smoothly. The faster that food and digestive by-products travel through the digestive tract, the less time there is for cancer-causing substances to work. Fiber also attracts water to the stool, which can dilute carcinogens and reduce their cancer-causing potential.

Some forms of soluble fiber — such as that found in oatmeal, oat bran, barley, and dried beans can even help lower blood cholesterol levels, reducing the risk of heart disease and stroke. How fiber acts on cholesterol is not fully understood.

Eating a diet low in fat and high in fiber can reduce your risk of colon cancer. In addition, eating lots of fruits and vegetables and other fiber-rich foods such as whole grains to replace fat in your diet can help reduce your risk of breast cancer.

The Many Sources of Fiber

Many doctors recommend that people who are at a high risk for colon cancer increase their intake of fiber to at least 35 grams a day. For example, a half-cup serving of ready-to-eat, wheat-bran cereal has 3.9 grams of fiber; a one-cup serving of cooked pinto beans has 7.4 grams of fiber; one medium artichoke has 6.5 grams of fiber; and one medium apple with skin has 3.7 grams of fiber.

Other good sources of fiber are navy beans, kidney beans, chickpeas, green peas, brussel sprouts, sweet potatoes, raisins, prunes, oranges, and whole-wheat bread.