Fiber gained worldwide attention in 1970 when Dr. Denis Burkitt, a renowned British physician, published a report pertaining to fiber. He observed that in countries where diets include large amounts of fiber, there were fewer cases of colon and rectal cancer, diverticulosis, hemorrhoids, hiatus hernia, appendicitis, varicose veins, gallstones and heart disease. Since these diseases were prevalent among Americans and other Westerners, the subject of fiber became a very popular topic in this country.

What is Fiber?  |  Increasing Fiber Intake  |  Table of Fiber-Rich Foods

What is Fiber?

• Dietary fiber can be defined as the part of plants resistant to digestion. Fiber is frequently referred to as roughage or bulk. Only foods from plants have fiber.

• The chemical components of dietary fiber include celluloses, lignins, gums, pectins, hemicelluloses and mucilages.

• Dietary fiber can be divided into two categories — those that are soluble in water and those that are insoluble in water. Soluble fiber forms a gel in water and includes gums, mucilages and pectins. Insoluble fiber does not dissolve in water. This fiber gives plants their structure. Its major components are celluloses, hemicelluloses and lignin.

• Fruits, vegetables and grains are not composed exclusively of either soluble or insoluble fibers. Rather, they contain various amounts of both types. Vegetables, wheat and most grain fibers contain more insoluble fiber; fruits, oats, barley and legumes contain more soluble fiber.

• Soluble fiber and insoluble fiber each have different effects on the human body:

Heart Disease: Soluble fiber, as found in fruits, dried beans and oat bran, has been shown to decrease blood cholesterol levels, thus may reduce the risk of heart disease. Blood pressure may be reduced by eating a high fiber diet, however other dietary factors are most likely involved.

Cancer: The American Cancer Society recommends a high fiber, low-fat diet to reduce the continued
risk of colon and rectal cancer. However, other genetic and environmental factors are probably involved, experts say.

Diabetes: Water-soluble fiber like pectin (in apples and oatmeal) can stabilize or decrease blood sugar levels and decrease insulin requirements.

Weight Control: Bulky, high fiber foods are usually low in calories, take longer to chew and make you feel full longer.

Constipation and Diverticulosis: Insoluble fiber is helpful in preventing and treating constipation and diverticulosis.
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Increasing Fiber Intake

Experts are still debating the question of how much fiber to consume. There is not an established Recommended Dietary Allowance (RDA) for fiber, however an intake between 20 to 35 grams of dietary fiber per day may be beneficial for most Americans.

Fruits and vegetables (especially those with edible skins and seeds), whole grain breads, cereals and pasta; bran and bran cereals, legumes, nuts and seeds are all high in fiber.

To increase fiber intake, gradually begin replacing foods lower in fiber with those higher in fiber. Keep in mind the following points, though:

• Some individuals may experience abdominal cramping and gas as their body adapts to a higher fiber intake, thus increase fiber intake gradually.

• Because fiber attracts water into the intestines, fluid intake should be increased. Aim for eight glasses of water per day.

• Do not overdo fiber intake. Too much fiber can inhibit the absorption of some important nutrients and cause gas, bloating and diarrhea.

• Do not rely on just one high fiber food (such as bran) to increase your fiber intake. Remember there are different types of fiber and they act differently, so choose from a variety of high fiber foods.
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Table of Fiber-Rich Foods

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