The well informed will be quick to tell you that fiber is a not a nutritive substance, and they would be quite correct in saying so. Yet fiber can have a significant impact on preventive health.
      If you have ever considered the reason the family dog occasionally eats grass, you may now have a clue as to why. It is believed by some that the fibrous content of the plant aids in the digestion of his food or, perhaps more to the point, the transit time of indigestible foods through the gastrointestinal tract to excretion. The good beast is not as discriminate as perhaps he should be about what he eats (unfortunately, we have at least that much in common with Fido...), and the routine consumption of fibrous materials takes a tremendous load off the digestive system, both his and our own. Ensuring there is sufficient fiber in your diet is also beneficial in many other ways, including keeping you off the grass on all fours.
      There has been a great deal of attention in the recent past about the potentially beneficial effects of a high fiber diet, as well as the fact that most people do not consume nearly enough of it. However, can there be too much of a good thing? As with all things, from vitamin A to zinc, you can overdo it. There are certain hazards associated with over consumption of fiber.

      All plant matter contains fiber. The insoluble form generally refers to the indigestible, structural components, such as the cell walls of the plant. The soluble form is derived from the intercellular parts, particularly in many plant foods, such as fruits, vegetables, and beans. Most plant foods consumed in normal diets contain both, though the amounts lean significantly toward the insoluble fraction.

      Although some will likely disagree with our canine analogy, the principle at least is sound. High-fiber diets impact the digestive process by adding bulk to the stool, and improving its transit time through the GI tract. In addition to contributing to the reduction of constipation and, in some cases, the relief of mild cases of diverticulosis, this process also reduces the absorption of less desirable dietary components by passing them through the system more rapidly.

      For a time there were many products on the market containing cellulose and guar gum, among others, that were believed to add sufficient bulk to the diet that individuals would “feel full” and therefore eat less. All this, of course, as a very convenient path to weight loss. Unfortunately, repetitive studies have not been able to substantiate anything of the sort. Weight management is a much more complex issue, and one that individuals cannot hope to solve by a high-fiber diet alone.

      It is probably safe to say that you cannot get too much fiber from ordinary diets, even those high in fiber content. Fiber supplementation is another matter, and individuals should be careful that they are not overdoing it. For the same reasons that fiber can be advantageous, very high concentrations of fiber in the GI tract can also bind essential nutrients, such as vitamins and minerals, causing these substances to pass through the system as well, rather than being absorbed. Such loss of nutrients is obviously counter-productive and should be avoided.
      Another important issue, plainly indicated on the labeling of supplements containing large amounts of fiber, is that inadequate fluid consumption can cause intestinal blockage which can lead to gastrointestinal problems. Be certain to consume adequate amounts of fluid when taking supplemental fiber!

      The best dietary sources of fiber are whole grains and cereals, pasta, brown rice, beans, nuts and seeds, and of course, fruits and vegetables, among others. The U.S. Food and Drug Administration (FDA) recommends in their Dietary Guidelines for Americans that adults consume at least six servings of whole grain products, including cereals, and five servings of fruits and vegetables per day. It is recommended that 25 grams of total dietary fiber be consumed on a daily basis.

      Supplemental fiber, soluble fiber in particular, should be seriously considered by most people. The reason is quite simple: on average, most individuals do not consume nearly enough fiber from dietary sources alone, and high-fiber diets have repeatedly been shown to be beneficial in overall preventive health. When selecting a fiber supplement, be certain that you are getting a significant amount of soluble fiber in the total mix.
      Additional information on dietary fiber supplements...

      A number of drugs are known to interact with dietary fiber, some in a negative way. A few of the more important interactions are listed here.
          - individuals taking blood sugar lowering drugs, such as glyburide (Diabeta, Euglucon, Glynase, Micronase, PresTab) need to be aware that the glucose-lowering effect of supplemental fiber may cause their blood sugar to fall to dangerously low levels
          - anyone taking the cholesterol-lowering drug lovastatin (Mevacor), who is also using a high soluble fiber supplement, should be aware that this combination can lead to reduced effectiveness of the drug

      There are a number of preventive health measures that have been attributed to diets high in dietary fiber. Those that are well documented include fiber’s ability to ease the effects of chronic constipation, reduce the effects of mild forms of diverticulosis, and aide in the reduction of blood cholesterol and blood sugar levels.
      Additional effects have been suggested, but are not well documented. Among the most important to watch is in the potential risk reduction of colon cancer.
      Dietary fiber has been the focus of considerable attention in the biomedical community of late. Read the latest on dietary fiber.