Fiber Supplements: Health Benefits & Side Effects

Many individuals may find it difficult to obtain an adequate amount of fiber from food sources alone.

Eating fiber-rich foods such as fruits, vegetables, whole grains, and legumes is considered the optimal approach for individuals to obtain their recommended daily fiber intake.

However, many individuals may find it difficult to obtain an adequate amount of fiber from food sources alone. In the United States, the average dietary fiber intake for children and adults is less than half of the recommended daily amounts.¹ As a result, some individuals elect to use the various fiber supplements on the market to maintain normal bowel function and prevent or decrease constipation.^1-3

The American Heart Association recommends that at least half of an individual’s daily grain intake come from whole grain sources. The number of servings per day depends on the age, gender, and caloric needs of the individual.² Dietary fiber can be divided into 2 categories: soluble and insoluble (Table 1^3,4).

Health Benefits of Fiber

Studies have investigated the possible health benefits of fiber, which include laxative effects, normalization of blood lipid levels, and attenuation of the blood glucose response (Online Table 2^1,3-6).

Table 2: Fiber Facts

^· The average American eats only 10 to 15 g of fiber per day.

^· According to the Academy of Nutrition and Dietetics, formerly the American Dietetic Association, the recommended daily amount of fiber is 25 g for women and 38 g for men. After 50 years of age, daily fiber needs decrease to 21 g for women and 30 g for men.

· The National Academy of Sciences Institute of Medicine and the American Heart Association recommendation for daily intake of fiber for children and adults is 14 g of dietary fiber per 1000 calories.

· According to a study published in 2009, viscous soluble fibers were associated with acute and long-term metabolic improvements in patients with type 2 diabetes mellitus via reductions in glycated hemoglobin, fasting and postprandial glycemia, insulinemia, and cardiovascular risk factors.

· Studies have reported that individuals with high intakes of dietary fiber appear to be at significantly lower risk for developing congestive heart disease, stroke, hypertension, diabetes, obesity, and certain gastrointestinal disorders.

· Increasing fiber intake may decrease blood pressure and serum cholesterol levels.

· Increased intake of soluble fiber may improve glycemia and insulin sensitivity in nondiabetic and diabetic individuals.

· Fiber supplementation in obese individuals significantly enhances weight loss.

· Increased fiber intake improves several gastrointestinal disorders, such as gastroesophageal reflux disease, duodenal ulcer, diverticulitis, constipation, and hemorrhoids.

Adapted from references 1, 3-6.

Pharmacists are in an ideal position to guide patients in the proper selection and appropriate use of fiber supplements. Some pharmacologic agents (eg, anticonvulsants, antidepressants, analgesics) are associated with an increased risk for constipation. Pharmacists can identify patients at risk for constipation and inform them about pharmacologic agents that may exacerbate constipation. Pharmacists can also make clinical recommendations on how to manage constipation.

Fiber supplements are available in formulations that may contain wheat dextrin, methylcellulose, psyllium husk, inulin, or calcium polycarbophil (Online Table 3).³ Dosage forms include sugar-free products, caplets, chewable tablets, capsules, wafers, and dissolvable powders in flavorless versions or various fruit flavors. The fruit-flavored gummy formulation is new and very popular. Some fiber supplements contain vitamins and/or minerals, such as calcium. Selection of fiber supplements may be based on patient preference, dosage form, cost, tolerability, and effectiveness.³

Table 3: Examples of Available Fiber Supplements

Brand Name (Active Ingredient)

Benefiber products (wheat dextrin)

Benefiber Fiber Caplets

Benefiber Plus Heart Health Powder

Benefiber Chewable Tablets

Benefiber Powder

Benefiber for Children

Benefiber Powder Plus Calcium (300 mg calcium)

Benefiber Stick Packets

Citrucel products (methylcellulose)

Fiber Choice (inulin)

Fiber Choice Chewable Tablets

Fiber Choice Sugar-Free Tablets

Fiber Choice Weight Management Tablets (contains chromium and picolinic acid)

Fiber Choice Plus Calcium (contains 500 mg and 200 IU of vitamin D)

Fiber Choice Plus Antioxidants

Fiber Choice Fruity Bites

FiberCon Caplets (calcium polycarbophil)

Hydrocil (psyllium)

Metamucil Clear and Natural (inulin)

Konsyl products (psyllium hydrophilic mucilloid)

Konsyl Fiber Caplets

Konsyl Original

Konsyl Easy Mix

Konsyl Fiber Easy to Swallow Capsules

L’il Critters Fiber Gummy Bears

Little Remedies Fiber Gummies

Metamucil (psyllium husk)

Metamucil Original

Metamucil Fiber Powder Drink Mixes

Metamucil Fiber MultiGrain Wafers

Metamucil Fiber MultiHealth Capsules

Metamucil Fiber Singles

Phillips Fiber Good Gummies

UniFiber (powdered cellulose)

Vitafusion Fiber Well Gummies

Vitafusion Fiber Well Weight Management Gummies

Patients, especially those with preexisting medical conditions, should be encouraged to discuss the need to increase fiber intake with their primary health care provider. It is recommended that individuals primarily increase their fiber intake by dietary means first because few extensive studies on fiber supplements have been conducted.³ If dietary modifications are not effective, supplements may be incorporated into the diet when appropriate.³

Patient Counseling

Patients electing to use fiber supplements should be informed that they may decrease the absorption of many pharmacologic agents. Therefore, patients should always be advised not to take supplements within 2 hours of taking other medications, and patients should express any concerns to their primary health care provider.³

When patients begin using fiber supplements or increase dietary fiber intake, they should al-ways gradually increase their intake over a few weeks to avoid or reduce adverse effects such as intestinal flatulence, bloating, diarrhea, and cramping.³ Adequate intake of water is advisable because inadequate fluid intake can reduce the effectiveness of a product and may cause intestinal or esophageal obstruction.³ To avoid choking in patients, many fiber supplement labels recommend taking the supplements with 8 oz of water.

Patients with preexisting medical conditions, such as those who must restrict fluid intake (eg, patients with significant renal dysfunction or with congestive heart failure), and patients currently taking any medications should discuss the use of fiber supplements with their primary health care provider prior to use in order to ensure appropriateness.³ Patients with intestinal ulcerations, stenosis, or disabling adhesions should avoid fiber supplements because of the possibility of fecal impaction or intestinal obstruction.³

Patients should be reminded to eat a healthy and balanced diet to obtain most of their daily fiber and to use fiber supplements as adjunctive therapy as warranted.

Ms. Terrie is a clinical pharmacy writer based in Haymarket, Virginia.

References:

• Anderson JW, Baird P, Davis RH Jr, et al. Health benefits of fiber. Nutr Rev. 2009;67(4):188-205.
• Whole grains and fiber. American Heart Association website. www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/HealthyDietGoals/Whole-Grains-and-Fiber_UCM_303249_Article.jsp. Accessed May 25, 2014.
• Rollins C. Functional and meal replacement foods. In: Krinsky D, Berardi R, Ferreri S, et al, eds. Handbook of Nonprescription Drugs. 17th ed. Washington, DC: American Pharmacists Association; 2012.
• Fiber. National Institutes of Health Medline Plus website. www.nlm.nih.gov/medlineplus/ency/article/002470.htm. Accessed May 25, 2014.
• Soluble versus insoluble fiber. Medline Plus website. www.nlm.nih.gov/medlineplus/ency/article/002136.htm. Accessed May 25, 2014.
• Fiber. Academy of Nutrition and Dietetics website. www.eatright.org/Public/content.aspx?id=6796. Accessed May 26, 2014.