Expert Health Articles

Why Fiber?

Martha Gonzalez, RD, LD, CLC

Blanchard Valley Health System

Most of us know that we need to eat more fiber. We are told day in and day out that as Americans we aren’t consuming adequate amounts of it, but many of us aren’t aware of the reasons behind this message or the benefits that fiber brings. When we look at the basics, fiber is the indigestible portion of foods. An important point is that fiber is only present in plants and is not present in animal products naturally. Fruits, vegetables, whole grains and legumes all contain significant amounts of fiber.

There are two types of fiber; soluble and insoluble. Most fibrous foods contain both types. Soluble fiber dissolves in water and is readily fermented in the colon forming gases. This type is also known as prebiotic fiber, due to it being the “food” for which our intestinal bacteria consume. Insoluble fiber does not dissolve in water and helps with the passage of food through our digestive system. Insoluble fiber is the kind that most of us think of with helping digestive functions.

According to the Academy of Nutrition and Dietetics, it is recommended that women consume 25 grams of fiber daily and men 38 grams. When looking at adults 50 and older, intake is reduced to 21 and 30 grams daily, respectively. It is also suggested to slowly increase your fiber intake if you’re not used to having an adequate intake to avoid gastrointestinal pain. One thing to note is that fiber is like a sponge in terms of water, high fiber intake can lead to nausea or constipation if adequate water is not consumed.

Besides aiding in digestion and helping maintain our intestinal bacteria, what are other benefits? Fiber is great for satiety by adding volume to food without adding calories, which can reduce appetite. Fiber also controls blood glucose levels by attracting water and forming a gel during the digestion of food. This slows the dumping of the stomach which prevents carbohydrates from interacting with enzymes and slowing down the absorption of glucose. This effect can help maintain blood glucose and insulin levels in people with diabetes and help lower the risk of developing diabetes.

Another advantage of fiber intake has shown to reduce risks of heart disease. LDL cholesterol (the “bad” cholesterol) is a significant contributor to heart disease. Our liver makes its own cholesterol, but we also eat additional via animal products. Soluble fiber has been shown to lower LDL cholesterol. The liver is responsible for cholesterol production and use, as well as the production of bile. Bile is used to break apart fat molecules from food to be absorbed and is made from LDL cholesterol. When fiber is consumed, fiber binds to cholesterol and bile, forcing them to be excreted. This, in turn, makes your body use more LDL cholesterol to form into bile, causing a lower amount to be in the blood, leading to a lower risk of heart disease.