The present emphasis on fiber and its role in various diseases dates back to the 1970s and the observations of Burkitt and others. They noted that in cultures with diets rich in fiber there was a relative rarity of diverticulosis or diverticulitis, gall-bladder disease, coronary heart disease, appendicitis, colorectal tumors or polyps, varicose veins, or deep vein thrombosis. In contrast, in the developed or Western cultures where the intake of dietary fiber is lower, these diseases are quite common. Burkitt also noted the emergence of these diseases in the United States and England after 1890. This seems to correlate with a new milling technique that yielded a low-fiber flour - white flour. He also showed that stool volume and transit speed correlated with the fiber content of the diet. The faster the transit time and the larger the volume, the lower is the incidence of these diseases.
Increasing dietary fiber usually also results in a reduction of intake of fats and sugar. Whether it is the increased fiber in the diet or a reduction in the intake of fat that are responsible for the reduction in the above mentioned diseases is still not quite clear. However, several studies have added proof that the fiber content of our diet is important to health.

What is fiber and what does it do?
An expert panel of scientists has defined dietary fiber as "the parts of plant materials in the diet which are resistant to digestion by human enzymes." The most frequent source of fiber are the nonstarch polysaccharides which are found in many fruits and vegetables. They are classified as soluble (oat bran, apples, citrus, pears, peas/beans, psyllium, etc.) and insoluble (wheat bran, cabbage, peas/beans, root vegetables, etc.). They both form bulk but the soluble ones are digested in the large intestine through bacterial action. It has also been shown that a diet generous in soluble fiber has actions other than just supplying the bulk.

Controlling Diabetes
Soluble fibers act mainly in the small intestine. They slow down the digestion of carbohydrates (sugars), which results in better glucose metabolism. Some patients with the adult-onset diabetes may actually be successfully treated with a high-fiber diet alone, and those on insulin, can often reduce their insulin requirements by adhering to a high-fiber diet.

Blood Cholesterol
Soluble fiber substances are also effective in reducing the blood cholesterol. This is especially true with psyllium, oat bran, fruits, and legumes. High soluble fiber diets may lower cholesterol and low- density lipoproteins (the 'bad' lipoproteins) by 8% to 15%.

Bowel Disorders
High fiber diets are helpful in delaying the progression of diverticulosis and, at least, reducing the bouts of diverticulitis. In many instances it helps reduce the symptoms of the Irritable Bowel Syndrome (IBS). It is generally accepted that a diet high in fiber is protective, or at least reduces the incidence, of colon polyps and colon cancer.

Preventing or Treating Constipation
Insoluble fiber retains water in the colon, resulting in a softer and larger stool. It is used effectively in treating constipation resulting from poor dietary habits. Bran is particularly rich in insoluble fiber.

Some Practical Aspects
While the best source of fiber are plant foods, fiber supplements may be helpful. A wide variety of foods supply a balanced intake of fiber, thus supplying both soluble and insoluble fiber. Some of the foods rich in fiber content include cereals and grains, brans, corn and whole grain rice. All fruits are rich in fiber with berries topping the list of both soluble and insoluble fiber. Vegetables have a varying amount of fiber but are important not only because of this varied content but also because they supply other important nutrients and vitamins. Some of the better sources include beans, cabbage, carrots, and lettuce.

In 1989 the Council on Scientific Affairs of the American Medical Association published a position paper on dietary fiber. The Council suggests that adequate fiber should be supplied by a diet including whole grain breads and cereals, vegetables, nuts, legumes and fruits. It is important, however, not to exaggerate the daily intake as excessive amounts (50-60 grams) of fiber may interfere with the absorption of vitamins and minerals. The present recommendation is for a daily intake of 25-30 grams of fiber or 15 grams per 1,000 calories. It is also important for individuals on low fiber diets to gradually increase the fiber intake. A sudden intake of a high-fiber diet may result in significant gas and abdominal discomfort. Always increase fluids (water, soup, broth, juices) while increasing your fiber intake

Sources of Soluble and Insoluble Fiber

Soluble Fiber; Beans, Fruits, Oatmeal/oat bran, psyllium, vegetables.

Insoluble Fiber; Cereal, Wheat/Wheat Bran, Whole grains.



Fruits Vegeatables
Apples, pears (with skin) Artichokes
Berries (Blackberries, Blueberries and rasberries) Beans (Baked, Black, Lima, Pinto)
Dates Broccoli
Figs Chick-peas
Prunes Lentils
  Winter Squash