The Benefits of Fiber and How It Works

— Written By Lethia Lee and last updated by Patricia Burch
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Most fiber is like other carbohydrates, made up of many glucose molecules. However, fiber does not break down into glucose before it gets to the colon, and often not even there. Even so, fiber does have effects on our digestion all along the way and has other benefits to our bodies. Here’s what fiber does in our bodies.

In the stomach, fiber is bulky, so it tends to make us feel full. However, insoluble fiber moves out of the stomach fast unless there is fat, protein, or soluble fiber to slow it down. Soluble fiber, especially the viscous types that hold onto water, will slow down the stomach emptying, especially when eaten with lots of fluid and some fat. This is at least partly why soluble fiber tends to decrease the glycemic effect of a meal – the contents of the stomach more gradually enter the small intestine, and from there, the blood.

In the small intestine is a similar process of insoluble fiber. It tends to speed transit time up and the gel-like soluble fiber slows things down.

In the colon, there is a whole other digestive world happening with the friendly bacteria.

Types of fiber that feed the colon: The fiber types that are most amenable to fermentation are soluble ones – gums, pectin’s, etc., found in such foods as berries, beans, flaxseeds, plums, apples, and oats, and some other fiber supplements, such as those using phylum and Guar gum. Insoluble fiber is found in such foods as vegetables, and the bran of grains etc. Wheat bran nuts and seeds aren’t available for much formation, but are still important in the colon. Not only does it provide bulk in the stool, its tendency to speed things along means that the formation will take place all along the length of the colon, including and near the end, where the majority of colon cancer occurs. Without insoluble fiber, most of the fermentation would take place in the top part of the colon, so the colon cells would get most of the benefit.

There are other benefits besides reducing the glycemic effect of meals and contributing to colon health. There is evidence that fiber may benefit us in other ways. As you can see there are so many benefits for having fiber in our bodies. Most of us don’t take it serious enough; it helps our food travel to the different parts of our bodies with more ease. So let’s consider what fiber does and how many benefits we have from eating foods that support good fiber health. There is evidence that it seems to help lower cholesterol and triglycerides, and it may also prevent ulcers, particularly at the beginning of the small intestine, diabetes, heart disease, and cancer.

I hope that we will have a better understanding of the importance of fiber in our bodies.

For more information on the importance of fiber contact Lethia Lee at The Sampson County Extension Office. 910-592-7161. Or

**Editor’s Note:  Lethia Lee is the EFNEP Program Assistant for the Expanded Food Nutrition Education Program with the N.C. Cooperative Extension, Sampson County Center.