The Health Benefits of Fiber Supplements

Help with Constipation, Diarrhea, IBS, IBD, and Diverticulosis

Psyllium Pills

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Fiber supplements are nutritional products that are available over the counter at drugstores, health food stores, and big box stores, as well as online. They come in a variety of formulations, including capsules, powders, and baked goods and contain one of three types of fiber: psyllium, methylcellulose, or polycarbophil. Fiber supplements typically are taken to help maintain healthy functioning of the digestive system, aid in weight loss, and help treat or prevent certain diseases and conditions. They generally are regarded as safe but some fiber supplements can cause side effects, such as bloating or gas, if not taken according to direction.

Health Benefits

Fiber is a type of carbohydrate that occurs naturally in fruits, vegetables, legumes, and whole grains. Despite being so plentiful, most Americans do not eat enough of the foods that naturally contain fiber and so supplements can help people to enjoy the many health benefits of fiber, which include helping to maintain optimal blood sugar and cholesterol levels. Adequate fiber intake also is associated with preventing certain cancers, heart disease, diabetes, and food allergies.

For optimal health, the Academy of Nutrition and Dietetics recommends adult men get at least 38 grams (g) of fiber per day and women get 25 g of fiber per day.

Most often, however, people take fiber supplements to help manage certain digestive problems. Soluble fiber absorbs water as it passes through the digestive track, transforming into a gel-like substance that helps slow digestion, making it especially useful for treating diarrhea. Insoluble fiber softens and adds bulk to stool so that it's easier to pass, and therefore can help relieve constipation, as well as prevent hemorrhoids and anal fissures that can result from passing hard stools. Adequate fiber also is important for maintaining regular bowel movements.

Fiber is filling and so can be helpful for weight loss and weight maintenance. Fiber supplements are sometimes included as part of an overall treatment plan for conditions such as irritable bowel syndrome (IBS), inflammatory bowel diseases (IBD) including Crohn's disease and ulcerative colitis, and diverticulosis. They should be used only with a doctor's direction in these circumstances.

Possible Side Effects

The potential side effects of fiber supplements include:

  • Gas and pain from gas
  • Abdominal bloating
  • Lowered blood glucose
  • Diarrhea or constipation (if taken in excess)
  • Unwanted weight loss

Because of the way fiber supplements bulk up in the intestinal tract and absorb surrounding materials, they can interfere with the body's ability to assimilate medications, vitamins, and nutrients.

Dosage and Preparation

Fiber supplements come in a variety of formulations: as powders to be mixed with water or another liquid; in capsules to be swallowed whole; and added to foods like crackers, cookies, cereals, and bars.

There are four types of fiber:

  • Psyllium: Made from the seeds of a plant in the Plantago genus, psyllium contains 70% soluble fiber and 30% insoluble fiber. It breaks down in the gut (fermentation) as a food source for the "good bacteria." For this reason, it can cause gas. Psyllium is used to treat constipation, irritable bowel syndrome (IBS), and diverticulosis. It has roughly 20 calories per tablespoon. Brand names include Metamucil, Fiberall, Hydrocil, Konsyl, and Serutan.
  • Methylcellulose: This non-allergenic, non-fermentable fiber is created from the cell walls of plants. It's a soluble fiber that pulls in water to create a softer stool and often is used to treat constipation and some causes of diarrhea, and maintain regular bowel movements. It can be used long term but may interfere with absorption of food and nutrients and so should not be taken at the same time as some prescription medications. Methylcellulose is sold under the brand name Citrucel.
  • Polycarbophil: Similar to methylcellulose, this soluble fiber also absorbs water in the intestinal tract and creates a bulkier, softer stool. It does not ferment and is not absorbed by the body. Polycarbophil may be used to treat constipation and bowel movement irregularities, but is not appropriate for people who have difficulty swallowing. It should not be taken at the same time as medication. Polycarbophil is sold under the brand names FiberCon, Fiber Lax, Equalactin, and Mitrolan.

Dosage will vary based on the product and the desired effects. It's generally advisable to start with a low dose of fiber and build up until you've reached the recommended total daily fiber intake which should include your dietary sources of fiber, as mentioned below.

What to Look For

When shopping for fiber supplements, you'll want to make sure it contains the type of fiber you want. And some supplements have added sugar, salt, flavorings, or dyes you may want to avoid. For these reasons, make sure to check the ingredients listed on the packaging before making your purchase.

Other Questions

What are the best dietary sources of fiber?

Whether or not you choose to supplement with fiber, it's important to include a variety of fiber-rich foods in your diet, such as:

  • Fresh fruit (e.g., pears, apples, strawberries, bananas)
  • Fresh vegetables (e.g., broccoli, Brussels sprouts, beets, and carrots)
  • Legumes (e.g.,lentils, split peas, kidney beans, chickpeas, black beans, pinto beans)
  • Whole grains (e.g., quinoa, oats, brown rice, millet, barley, farro)
  • Other sources (e.g., popcorn, cereal, chia seeds, flax seeds)

Is it a good idea to take a fiber supplement every day?

There is no evidence to suggest that taking daily fiber supplements is harmful and many people do make it part of their everyday health regimen.

What time of day is best?

Recommendations for when and how frequently to take fiber supplements vary. You may want to divide your daily dose into two or three portions to reduce bloating and gas that could occur when taking a large dose all at once. To avoid malabsorption, it's important to take medications or vitamins either one hour before, or two hours after taking fiber supplements. If using a powdered form of fiber, dissolve it well. Always drink plenty of water when taking fiber supplements.

A Word from VeryWell

Fiber supplements are available over the counter and are considered safe for most people. If you have a medical condition you think might improve by taking a fiber supplement, though, talk to your doctor first. If you are experiencing diarrhea or constipation regularly, you may need to be evaluated for a digestive condition before starting to treat it with fiber.

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