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You've heard about the benefits of healthy fiber before. But you might not think they apply to you. You might associate "healthy fiber" with prunes and constipation.

This misconception grates on researchers. "When I tell people that I study the effects of fiber, they always assume I'm talking constipation," says Kelly A. Tappenden, PhD, RD, a spokeswoman for the American Gastroenterological Association. "I'm not. The subject is much more complex than that."

In fact, there are many benefits of healthy fiber for digestive health. Studies show that fiber is important for people of any age, and it helps treat and prevent a number of conditions -- ranging from severe acid reflux (known as gastroesophageal reflux disease, or GERD) to inflammatory bowel syndrome (IBS) to obesity and diverticulitis. Here’s how healthy fiber helps digestive health -- and why you need to get more of it.

Benefits of Healthy Fiber for Digestive Health

Here is the evidence on some of the benefits of healthy fiber for digestive health:

  • Regularity. Let's start with the one you knew already. Fiber, particularly insoluble fiber, can help people prevent constipation. It bulks up stools and keeps food moving through the digestive tract.
  • Healthy bacteria. You might have heard of probiotoics -- healthy bacteria that live in your intestines. Some types of soluble fiber are considered a prebiotic -- a fuel that feeds these healthy bacteria and increases their numbers, Tappenden says. What do these bacteria do? They boost digestive health. And some studies suggest that they might have far-reaching effects, perhaps improving the immune response and preventing allergy development, Tappenden says. 
  • Diverticulitis. This painful condition is caused when pockets in the intestines rupture and become infected. One study found that a diet high in healthy fiber -- insoluble fiber in particular -- could reduce the risk of diverticular disease by 40%. Other studies suggest that a high-fiber diet can ease symptoms in people who have the condition and prevent future exacerbations.
  • Gastroesophageal reflux disorder (GERD) and ulcers. The evidence is not clear yet. But some studies have suggested that a high-fiber diet is associated with a lower risk of GERD and duodenal ulcers. Some soluble fibers have been linked with lower levels of gastric acid.
  • Irritable bowel syndrome (IBS.) There is some evidence that certain types of fiber supplements – such as those containing psyllium, guar gum, and methylcellulose -- could help with IBS. However, high-fiber wheat bran seems to worsen symptoms.

Other health benefits. Fiber's benefits aren't confined to digestive health. Studies have found that healthy fiber can also lower cholesterol, promote healthy blood sugar levels, reduce the risk of cardiovascular disease, and help people lose weight or maintain a healthy weight.

Healthy Fiber Basics

Fiber is the general name for material in vegetables, fruits, and grains that our bodies can't digest fully. There are two terms used to describe fiber:

  • Soluble fiber breaks down into a gel in the intestines. As it passes through your GI tract, soluble fiber absorbs water and slows down digestion. Soluble fiber is found in oatmeal, nuts, beans, apples, and blueberries.
  • Insoluble fiber doesn’t really break down in the intestines. It passes through the body mostly intact. Insoluble fiber speeds up digestion -- it causes what experts call "intestinal hurry." Insoluble fiber is in foods like seeds, grains, and the stringy parts or skins of fruits and vegetables.

For general digestive health, it’s important to get plenty of both kinds of fiber.

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