Daily Intake Of Dietary Fiber

Dietary fiber is a term used to describe a heterogeneous group of plant food components that are resistant to human digestive enzymes. It is as a non-starch polysaccharide, a type of carbohydrate. Fiber is found exclusively in plant foods. There is no RDA but we should eat at least 25 grams per day.

There are two basic categories of dietary fiber:- water insoluble and water soluble. These include - cellulose, hemicellulose, gums, pectin, psyllium and lignin.

Insoluble fibers are found in the skin, peel, and husks of fruit, vegetables and whole grain products. The inclusion of this fiber in a low-fat diet may reduce the risk for colon cancer. Insoluble fibers also aid in the treatment of constipation and diverticulosis.

Psyllium, oat products, barley and beans are good sources of gum, a type of soluble fiber. Gums and pectin influence absorption in the stomach and small intestine. By binding with bile acids, they decrease fat absorption and lower cholesterol levels. They coat the stomach lining, and by doing so they slow sugar absorption, regulating blood sugar levels, which is useful to diabetics since it reduces the amount of insulin needed at any one time.

Lignin also binds with bile acids, assists in lowering cholesterol levels and helps speed up food through the digestive tract.

Dietary patterns emphasizing foods high in complex carbohydrates and fiber are associated with lower rates of diverticulosis, reduced risk of coronary heart disease and diabetes mellitus, lower blood glucose and blood lipid levels, and some types of cancer.

Epidemiologic evidence suggests that frequent consumption of vegetables and fruits, particularly dark green and cruciferous vegetables (such as cabbage and broccoli), may lower the risk for cancers of the lung, bladder and alimentary tract.

Whole-grain cereals, whole-grain bread, other grain bakery products and pasta, legumes - kidney beans, lima beans, navy beans, and split peas, fruits, especially the skin and edible seeds are the best source of fiber.

"If you think that the perilous conditions of our diet is worldwide in scope, just look at the 'underprivileged' areas of rural Africa. In the year 1975, the southern areas of rural Africa avoided the major scourges of the modern world. British doctors found in their research on rural African villages that cancer of the colon and the rectum is extremely rare, and that there is no appendicitis, hemorrhoids, obesity, heart attacks, varicose veins, phlebitis, or diverticulosis of the colon. As if this evidence were not enough proof that something is wrong with our diet, it has been shown that Africans develop the same diseases we have as soon as they adopt a Western diet-that is, as soon as they cut their intake of roughage." [David Reuben, 1975. The Save Your Life Diet.]

Psyllium is an especially attractive hybrid intervention in that it is well tolerated, lowers LDL-cholesterol by 10% to 20%, has no adverse effects on triglycerides, high-density-lipoprotein (HDL) cholesterol, or serum glucose, and is readily available and fairly inexpensive. It has a long history of use without any evidence of long-term adverse effects.

An article in JAMA estimated that oat bran supplementation (90 gm per day) was a much more cost-effective method of lowering serum cholesterol than either cholestyramine or colestipol. In addition, high-fibre diets may decrease risk of colon cancer, improve glucose tolerance, lower blood pressure, and assist in weight loss.

- Kinosian, B.P., and Eisenberg, J.M.: Cutting into cholesterol: Cost-effective alternatives for treating hypercholesterolemia. JAMA 259:2249, 1988

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