The Best Fiber Supplement for Diverticulitis

Close-up of psyllium husk seeds sit on a counter.
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Diverticulitis is a condition characterized by inflammation or infection in abnormal pouches or sacs in the lining of the large intestine. People with this disorder commonly have an insufficient intake of dietary fiber. To prevent diverticulitis, your doctor may recommend fiber supplements that contain either psyllium or methylcellulose as their active ingredients. Fiber supplements are not recommended if you have an active case of diverticulitis.

Diverticulitis Basics

Diverticulitis develops in people who have a disorder called diverticulosis. Diverticulosis triggers the formation of unusual sacs and pouches in your intestine, while diverticulitis is an infection or inflammation that can subsequently develop in these abnormal bulges. Doctors can't definitively say that a low-fiber diet causes diverticulosis. But there are very strong links between the disorder and poor fiber consumption. Roughly 10 percent of Americans past the age of 40 have diverticulosis, according to the National Digestive Diseases Information Clearinghouse. And roughly 10 to 25 percent of those with diverticulosis will eventually develop diverticulitis. Doctors commonly group diverticulosis and diverticulitis under the term diverticular disease.


Bulk-Forming Laxatives

Psyllium and methylcellulose belong to a class of substances called bulk-forming laxatives. They absorb the liquid in your intestines and soften your stool as it passes through your body. Psyllium comes from the seed husks of a plant called Plantago ovata, while methylcellulose is a modified form of cellulose, which forms the cell walls in certain plant species. Fiber supplements that contain psyllium as their active ingredient include Metamucil, Serutan, Fiberall and Genfiber. Supplements that contain methylcellulose include Citrucel, Citrucel SF and Citrucel Lax.


Understanding Fiber's Role

Fiber supplements are not typically used to treat active cases of diverticulitis. But they can lower your risk of developing diverticulitis by reducing the pressure on the walls of your intestine. If you already have diverticulitis, possible treatments include bed rest, pain medications and antibiotics. Your doctor may also ask you to avoid foods and drinks that can worsen your condition, including peas, beans, cucumber, pickles, strawberries, popcorn, corn, coarse grains, tomatoes, dried fruits, seeds, nuts, alcohol, coffee and tea.


Typically, you will take psyllium or methylcellulose one to three times a day in doses that contain anywhere from 2 to 3.5 g of fiber. Always take these supplements with at least 8 oz. of water. You can also help to prevent diverticulitis by increasing your intake of foods that contain significant dietary fiber, including fruits, vegetables, whole grains and whole-grain products. If you have a severe case of diverticulitis, treatment commonly includes hospitalization and use of intravenous antibiotics. In certain circumstances, you may need surgery. Consult your doctor before you use psyllium or methylcellulose products.