Q: I’m confused about all the different types of fiber. What is functional fiber?
A: You’re right – it is confusing. Growing research shows that fiber is not all the same. Functional fiber is isolated fiber added to a food or supplement. Dietary fiber refers to fiber that occurs naturally in foods, including vegetables, fruits, grain products, legumes, nuts and seeds.
Regardless of whether fiber is added to a food or occurs there naturally, different forms seem to differ in potential health benefits. Some types of fiber may help reduce problems with constipation. Other fiber tends to form a gel within the digestive tract, binding up cholesterol and helping to reduce its level in the blood. Still other fiber is a type that bacteria in the gut can ferment. This creates compounds that emerging research suggests may help keep colon cells healthy and reduce inflammation. More work is needed to better understand all these potential roles.
The fiber added to fortified foods (like certain breads, cereals, yogurts and more) tends to be inulin or gums. These fibers provide different health benefits than the dietary fibers from whole grains, vegetables, fruits, beans, nuts and seeds.
Laboratory studies can isolate individual types of fiber to study the ways they may reduce risk of cancer, heart disease and diabetes. But trying to interpret results from studies with people can be complicated. That’s because foods contain a mixture of different types of dietary fiber, and these foods also tend to be good sources of a variety of vitamins, minerals and natural plant compounds (phytochemicals). That makes it hard to tell how much of the link between high-fiber diets and better health comes from fiber, from these other healthful substances, from their combined effects, or even from a potential help with weight control from these foods.
Learn more: The Facts About Fiber