Getting enough fiber is an important first step in ensuring good digestive health.
Getting enough fiber is an important first step in ensuring good digestive health.
Many people in the United States find it difficult to meet the recommended daily intake of dietary fiber. In fact, the average American consumes only 10 to 15 g of fiber each day.1
According to the Academy of Nutrition and Dietetics, formerly the American Dietetic Association, the recommended daily fiber intake is 25 g for women and 38 g for men. After age 50 years, daily fiber needs decrease to 21 g for women and 30 g for men.2
The National Academy of Sciences’ Institute of Medicine and the American Heart Association, on the other hand, recommend that children and adults consume 14 g of dietary fiber per 1000 calories, which appears to be the amount required to promote heart health.3-5 Adequate consumption of dietary fiber is critical to maintaining normal bowel function and is recommended for prevention and treatment of constipation.3 In addition, studies have demonstrated that adequate daily fiber intake confers multiple health benefits and has the potential to prevent or decrease the risk of certain health problems.2-6
Why Fiber Matters
High dietary fiber intake may decrease one’s risk of coronary heart disease (CHD), stroke, hypertension, diabetes, obesity, and colon cancer.2-6 Multiple epidemiologic studies have found a correlation between high dietary fiber intake and decreased risk of CHD and cardiovascular disease (CVD).4 Increasing fiber intake via whole grains, legumes, guar gum, pectin, and psyllium also appears to lower serum cholesterol levels and decrease CHD risks.4 High fiber intake may be beneficial to those with gastroesophageal reflux disease, duodenal ulcer, diverticulitis, and hemorrhoids.2-6
Studies have also showed that adequate intake of soluble fiber can help improve glycemic management for diabetics.3-5 Other health benefits associated with adequate fiber intake include improved management of irritable bowel syndrome, increased weight loss, and restored bowel regularity for those on low-carbohydrate diets.3-5 Results from a study published in the June 2012 issue of the Journal of Clinical Endocrinology & Metabolism suggest that teenagers who do not consume enough fiber are at increased risk of CVD and diabetes.7
Consuming fiber-rich foods such as fruits, vegetables, whole grains, legumes, and beans is considered ideal, but many people may find it difficult to obtain their daily required fiber intake through dietary means alone.
Types of Fiber
Dietary fiber can be divided into 2 basic categories: soluble and insoluble (Table).6,8 Many people use fiber supplement products, also known as bulk forming laxatives, to meet their recommended daily fiber intake requirement and to maintain normal bowel function. Because some pharmacologic agents (eg, anticonvulsants, antidepressants, and analgesics) may be associated with an increased risk of constipation, pharmacists are in a pivotal position to identify patients who face this risk and inform them about this possible adverse effect.
Patients should be encouraged to discuss increasing their fiber intake with their primary health care provider. It is recommended that people first try to increase their fiber intake via dietary means since few extensive studies on fiber supplements have been conducted.3 If dietary modifications are not effective, patients may incorporate supplements into their diet.3 However, those with pre-existing health conditions should always discuss the use of these supplements with their primary health care provider. Selection of fiber supplements may be based upon patient preference, dosage form, cost, tolerability, and effectiveness.3
Pharmacists can assist patients in the proper selection of fiber supplements and offer counseling on the products’ proper use. There are a variety of fiber supplements available, containing ingredients such as wheat dextrin, methylcellulose, psyllium husks, inulin, and calcium polycarbophil. Fiber supplements are available in several dosage formulations, including sugar-free versions, caplets, tablets, capsules, wafers, and dissolvable powders in flavorless versions or various fruit flavors. Some fiber supplements contain calcium and other vitamins or minerals as well.3,9-12
During counseling, pharmacists should remind patients that fiber supplements can decrease the absorption of many pharmacologic agents, so they should not take supplements within 2 hours of taking other medications and should report any concerns to their primary health care provider.3
Patients should also be advised to gradually increase their fiber intake over a few weeks and simultaneously increase their water intake to reduce the risk of adverse effects such as intestinal flatulence, bloating, diarrhea, and cramping.3
Many fiber supplement product labels recommend taking the supplements with 8 oz of water to reduce the risk of choking.3,9-12 Patients who are currently taking any medications and specifically those with medical conditions that require restricted fluid intake (ie, significant renal dysfunction or chronic heart failure), should discuss whether fiber supplements are appropriate for them with their primary health care provider. 3,9-12 Patients with intestinal ulcerations, stenosis, or disabling adhesions should avoid fiber supplements because of the risk of fecal impaction or intestinal obstruction.3
Finally, patients should also be reminded to obtain most of their daily fiber from dietary means and that fiber supplements should never be a substitute for a balanced, fiber-rich diet that contains other essential vitamins and minerals necessary for optimal health.
Table. Examples of OTC Fiber Supplements
Brand Name (Active Ingredient)
Benefiber Products (wheat dextrin)
Benefiber Plus Heart Health Caplets
Benefiber Assorted Fruit Chewables
Benefiber Plus Calcium Chewables (300 mg calcium)
Benefiber Stick Packs
Novartis Consumer Health, Inc
Citrucel Products With SmartFiber (methylcellulose)
Citrucel Powder (also available sugar free)
Fiber Choice (inulin)
Fiber Choice Chewable Tablets
Fiber Choice Sugar-Free Tablets
Fiber Choice Weight Management Tablets (contains chromium)
Fiber Choice Plus Calcium (contains calcium 500 mg and vitamin D 200 IU)
Fiber Choice Plus Antioxidants
FiberCon Caplets (calcium polycarbophil)
Pfizer Consumer Healthcare
Hydrocil Instant Natural Fiber Laxative (psyllium)
Konsyl Products (psyllium)
Konsyl Original Formula Powder
Konsyl Easy Mix Powder
Konsyl Fiber Caplets
Metamucil Clear and Natural (inulin)
Metamucil Fiber Powder
Metamucil Fiber MultiGrain Wafers
Metamucil Fiber Capsules
Metamucil Fiber Singles
Procter & Gamble
iFiber (powdered cellulose)
Ms. Terrie is a clinical pharmacy writer based in Haymarket, Virginia.
1. Fiber. National Institutes of Health Medline Plus website. http://www.nlm.nih.gov/medlineplus/ency/article/002470.htm Accessed June 6, 2012
2. Fiber. American Academy of Nutrition and Dietetics website. http://www.eatright.org/Public/content.aspx?id=6796
3. Weitzel Kristen et al. In Krinsky D. Berardi R, Ferreri S. et al, eds. Handbook of Nonprescription Drugs 17th ed. Washington, DC: American Pharmacists Association; 2012
4. Rollins, Carol. 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
5. Fiber and Children’s Diets. American Heart Association website. http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/Fiber-and-Childrens-Diets_UCM_305981_Article.jsp
6. Anderson JW, Baird P, Davis RH Jr, Ferreri S, Knudtson M, Koraym A, Waters V, Williams CL. Health benefits of dietary fiber. Nutr Rev. 2009 Apr; 67(4):188-205.
7. Low Fiber Diet May Raise Teens’ Risk for Heart Disease, Diabetes. Medline Plus website. http://www.nlm.nih.gov/medlineplus/news/fullstory_125925.html
8. Soluble versus insoluble fiber. Medline Plus website http://www.nlm.nih.gov/medlineplus/ency/article/002136.htm
9. Metamucil product information. Proctor and Gamble website www.metamucil.com. Accessed October 29, 2009
10. Fibercon product information. Wyeth Consumer Health www.fibercon.com. Accessed October 29, 2009
11. Citrucel product information. GlaxoSmithKline Consumer Healthcare www.citrucel.com/Ch5_FAQ.aspx#crush. Accessed October 29,2009
12. Inulin fiber benefits. Proctor and Gamble website. www.metamucil.com/clear-and-natural.php?ref=f. Accessed June 6, 2012.