Glossary of Fiber Terms Used in Writing about Irritable Bowel Syndrome (IBS)
Terminology Problems
The discussion about appropriate types of fiber in the therapy of Irritable Bowel Syndrome is hampered by a number of misconceptions about fiber. What has been holding me up in writing a simple Fiber 101b post, the second part of the primer on fiber, has been the need to explain several distinctions among types of fiber, that is so much of what I mean when I say fiber.
These are some the terms used on this and other sites:
- Dietary Fiber
- Insoluble Fiber (IF)
- Soluble Fiber (SF)
- Soluble Fiber Supplement (SFS)
- TV ads for “Fiber”
Putting the explanation of terms into an article, I think, will make your eyes glaze over. That will happen if what I say is in conflict with what you know. So, this is the fiber glossary, the words and terms for talking about fiber. Some of what is on this page will be new to your understanding of fiber.
Glossary
Fiber
- Not a specific term. It doesn’t describe the food, or the supplements, that supply fiber. It may be used to describe a daily amount of fiber.
Dietary Fiber
- This is more specific. It is part of the break down of the carbohydrates count in a nutrition label. The other part of the carbohydrate count is sugars. Dietary fiber contributes only a small amount of energy/calories, because it is the residue from plant foods.1 Recommended daily allowances are talking about measurable totals of different kinds of dietary fiber.
Soluble Fiber (SF)
- Soluble Fiber comes from plants that are sources of gums used in the preparation of foods, as thickeners, for example. In Heather’s system of Eating for IBS, soluble fiber is also starches that are found in rice, potatoes, and sweet potatoes, and are useful to put the gastrocolic reflex to sleep before eating a (more-or-less) regular meal.
Soluble Fiber Supplements (SFS)
- Soluble Fiber Supplements are commercially available varieties of the first kind of SF above, the plants that produce gums that dissolve completely in water. Some examples are guar gum used in the old Benefiber ™, acacia gum used in Heather’s Organic Acacia Tummy Fiber ™, and inulin from chicory root, sometimes used as a sweetener, and the only ingredient in FiberSure ™.
Insoluble Fiber (IF)
- This is plant materials–fibers–that do not dissolve in water. Insoluble fiber is what used to be called “roughage.” It is usually what we understand doctors to be saying when they say “Increase fiber.” My bad example is Metamucil ™, which is made from psyllium (a kind of seed) husks. They add bulk to the stool, hastening its movement through the intestines. Bran and various crunchy, rough cereals are sources of insoluble fiber (IF); also raw vegetables such as carrots. The skins and seeds of fruit and vegetables are other sources, as are nuts. This is what doctors still give as the kind of stuff to eat as part of a “high fiber diet.”
None of these things is easily tolerated by a person with IBS.
TV Ads for “Fiber”
- In the United States there is an ad for FiberCon caplets, ™ which are “Calcium polycarbophil 625 mg equivalent to 500 mg polycarbophil.” Their labeling suggests that the caplets should not be used more than 7 days without a doctor’s approval. The ingredient is the same as that in Equalactin ™. The interesting point is the way the ads play on the popular conception of a “high fiber diet,” and suggest that such a diet is impossible to follow because we’d be eating fiber all day. So, why not take their caplets? Well, because polycarbophil is a “bulk-forming” laxative–roughage, or IF–and may give some problems to people with IBS.
NOTE
In the past, in the archived posts on this blog, I have used SF and SFS interchangeably, meaning supplements. Heather’s site also has used the terms interchangeably in the past, in the meaning of both supplements and the soluble element of starches such as rice and potatoes, and bananas.
Neither of us is technically wrong, just different. SF, including both starches and SFS, is PREbiotic, a growing medium for the good bacteria that we call PRObiotics.
- 1 Shirley S. Lorenzani, “Dietary Fiber: Its Surprising Range of Therapeutic and Protective Health Benefits,” Good Health Guides (New Canaan, Connecticut: Keats Publishing) 1988. [↩]
