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Dietary and Fiber Supplements – What the Community Pharmacist Needs to Know Fiber benefits for digestive health, lowering & healthy control

The health benefits of have been well-studied and are widely recognized by authoritative health organizations in the United States.1,2,3 The utility of fiber as a bulk- forming for treating occasional or for maintaining regularity has been appreciated for many years. Other key health benefits of dietary have been increasingly recognized, including:

• Maintaining healthy glycemic control, and • Reducing the risk of coronary heart disease by lowering cholesterol

What is the recommended daily fiber intake? The Institute of Medicine of the National Academy of Science and the U.S. Department of Agriculture recognize fiber as an important part of a healthy and has issued guidelines for daily fiber intake that are based on age, gender and energy intake.1,2 Yet despite the availability of good dietary sources of fiber, many Americans consume less than half of the recommended daily fiber amount.4,5

• Daily recommended goal: 14 g of fiber per 1,000 kilocalories of consumed1,2 - Adult women ages 19 to 50 years: 25 g/day - Adult men ages 19 to 50 years: 38 g/day

Did you know? Fewer than 5% of people get enough fiber from the food they eat.4

Do your patients need a fiber supplement? • Have your patients keep a food diary for a week to document their fiber intake. • Review the food diary and make suggestions on increasing fiber through diet or supplements, if needed. • Encourage your patients to have a conversation with their doctor before beginning a fiber supplement regimen to ensure it is right for them.

1 United States Department of Agriculture. May 2010. Available at: http://www.cnpp.usda.gov/DGAs2010- DGACReport.htm. Accessed on May 19, 2014. 2 Institute of Medicine of the National Academies. The National Academies Press. Available at: http://www.iom. edu/Reports/2002/Dietary-Reference-Intakes-for-Energy--Fiber-Fat-Fatty-Acids-Cholesterol-Protein- and-Amino-Acids.aspx. Accessed on May 19, 2014. 3 Slavin JL. J Am Diet Assoc. 2008;108:1716-1731. 4USDA WWEIA Report Dietary Fiber. Available at http://www.ars.usda.gov/Services/docs.htm?docid=13793. Accessed May 19, 2014. Sponsored by P&G 5 Park Y, et al. JAMA. 2005;294:2849-2857. Personal Health Care Not All Fibers Are Created Equal Common Dietary Sources of Fiber3

Dietary fiber is defined as “the nondigestible Serving = one (3.7 g fiber) and (a complex ) present in and isolated • For women, this is 15% of daily nondigestible carbohydrates that have physiologic effects.”6,7 intake of fiber. However, not all fibers meeting this definition deliver clinically • For men, this is almost 10% of proven health benefits. the daily intake of fiber.

Dietary fibers can differ considerably in their chemical and Serving = 1/2 cup of raw physical properties, including their , and (1.3 g fiber) fermentability. These factors influence the physiologic effects • For women, this is 5% of daily intake 8,9,10,11,12 and health benefits of fiber. Most dietary fiber sources, of fiber. such as , and whole grains, are a mixture of both • For men, this is less than 4% of the soluble and insoluble fibers. daily intake of fiber.

Physical Properties Drive the Serving = 1 cup of cooked brown Health Benefits of Fiber8, 9, 10, 11, 12 (3.5 g fiber) • For women, this is 14% of daily intake of fiber. • For men, this is 9% of the daily intake of fiber. Ability to dissolve in Solubility fluids in the GI tract Serving = 1 oz. nuts (2.6 g fiber) • For women, this is 10% of daily Viscosity/ Ability to thicken or intake of fiber. gel-formation form gels when mixed • For men, this is almost 7% of with fluids the daily intake of fiber.

Degree to which the fiber Fermentability is degraded/digested by in the colon Help Your Patients Get More Daily Fiber (forming gases and short

chain fatty acids) Encourage your patients to get more fiber in their diet:

• Substitute high-fiber for lower-fiber foods where appropriate (e.g., whole rather than );

• Incorporate fiber supplements into muffin mixes, 6 Anderson JW. J Med. 2009;2:87-91 , etc. 7 Panel on Macronutrients, Panel on the Definition of Dietary Fiber, Subcommittee on Upper Reference Levels of , Subcommittee on Interpretation and Uses of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. Washington, DC: The National Academies Press; 2002/2005. Remember to counsel patients that when increasing the amount 8 McRorie JW, et al. Clinical Nursing Studies, 2013, 1(4): 82-92. of fiber, they should go slow, increase in small increments — 9 Dikeman CL, et al. Crit Rev Food Sci Nutr. 2006;46:649-663. 11 10 Guillon F, et al. Food Res Int. 2003;33:233-245. every one to two weeks — until reaching the target goal. 11 Chutkan R, et al. J Am Acad Nurse Pract. 2012;24:476-487. 12 Anderson JW, et al. Nutr Rev. 2009;67:188-205. Health Benefits of Fibers/Fiber Supplements In contrast to some soluble viscous fibers, soluble non-viscous fibers Although dietary sources of fiber contribute important (e.g., wheat and ) and insoluble fibers have not been and nutrients, fiber supplements can be shown to have cholesterol-lowering properties.6, 8,11,13,14,15,16 Some important to help meet the recommended daily soluble viscous fibers also have been shown to normalize glycemic fiber intake. Fiber supplements are a convenient control and to treat occasional constipation.8,11 Insoluble fibers have way to increase fiber intake, but not all fibers are the not demonstrated glycemic effects, but do have a laxative benefit if same.6,8,11,12 they are sufficiently “gritty,” whereas soluble nonviscous fibers (e.g., wheat dextrin and inulin) have not been clinically shown to confer Understanding and communicating these differences these health benefits.8,11 is essential to pharmacists to help tailor their recommendations of dietary fiber and fiber supplements and / fibers are the only fibers that to better meet individual health goals of their patients. have been recognized by the FDA for their cardiovascular Health benefits vary among different fibers. Some benefits. The FDA concluded that: “Diets rich in soluble fiber, soluble viscous fibers, such as psyllium and such as that found in whole oats or barley and psyllium (β-), form a gel that binds some bile acids and husk, reduce the risk of coronary heart disease.” 17 cholesterol to help lower blood cholesterol.6, 8,11,13,14,15,16

+ positive efect – no effect or no data +/- minimal effect *if particles are sufficiently large/coarse

No Water-Holding Capacity, Water-Holding Capacity, No Gel Formation Gel Formation Health Benefits6,8,11,12 (based on data from published Insoluble Soluble Soluble Viscous information/literature) Non-Viscous Wheat Methyl- Inulin Psyllium Wheat dextrin (Fiber polycarbophil β-glucan (Benefiber®) Choice®) (FiberCon®) (Citrucel®) (Oats) (Metamucil®)

Helps maintain healthy blood glucose levels – – – – – + +

Reduces the risk of by lowering elevated serum – – – – +/– + + cholesterol levels

Treats occasional constipation +* – – + + – +

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13 Kirby RW, et al. Am J Clin Nutr. 1981;34:824-829. 14 Everson GT, et al. J Lipid Res 1992;33:1183–1192. 15 Anderson JW. Arch Intern Med. 1988;148:292-296. 16 Wolever TM, et al. Am J Clin Nutr. 1994;59:1055–1059. 17Food and Drug Administration, US Department of Health and Human Services. Code of Federal Regulations, Title 21, Volume 2, Section 101.81. Health claims: Soluble fiber from certain foods and risk of coronary heart disease (CHD). Available at: http://www.accessdata.fda.gov/scripts cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=101.81. Accessed May 19, 2014. Health Benefits of Psyllium Fiber Effect of Soluble Viscous Fibers Regular consumption of psyllium fiber may provide a number (such as Psyllium) on Cholesterol13,14,15,16 of health benefits due to its ability to form a viscous gel. Although many pharmacists may recognize the benefits of Reduced serum Fiber forms a gel psyllium in treating constipation, psyllium offers a number of cholesterol other health benefits. (mostly LDL)

Viscosity of psyllium is associated with additional benefits due to the ability to form a gel-like substance that traps Binds bile some , carbohydrates, bile acids and cholesterol acids in to help maintain healthy blood levels and lower the small cholesterol.6,8,9,11 intestine

Sugar Slow release of sugars reabsorption is inhibited Bile acid and Cholesterol Carbohydrates uses serum cholesterol Increased to synthesize bile acid more bile elimination in In the , Metamucil When the gel moves down the gels and traps some sugars, intestine, trapped sugars are carbohydrates, bile acids and slowly released and absorbed cholesterol. Carbohydrates are into the body, helping maintain Healthy Glucose Control Benefits slowly metabolized to sugars. healthy blood-sugar levels. Bile-acid reabsorption is Viscous soluble fibers have been shown to attenuate glucose inhibited. The gel also gently and responses in healthy subjects.20 Evidence suggests removes waste and some bile acids to reduce cholesterol. that psyllium fiber can help maintain a healthy blood-glucose

level by modulating postprandial glycemia when used in conjunction with dietary control.21,22,23,24

Given the data associating psyllium with reduced postprandial Heart Disease and Cholesterol Benefits and fasting blood glucose levels, dosages of medications to control blood glucose may need to be adjusted in patients using • A meta-analysis of eight randomized, controlled trials found psyllium for fiber supplementation. that psyllium fiber significantly lowered total cholesterol, low-density lipoprotein-cholesterol and serum ratios of apolipoprotein (apo) B to apo A-I beyond reductions seen with a Pharmacists Play an Important Role low-fat diet only.18 Pharmacists can help patients improve their diet and their • Longer-term studies suggest that fiber can play an important health. Talk with your patients about the current dietary fiber role in sustaining cholesterol-lowering benefits, with the use of intake recommendations and ways to increase their daily intake psyllium shown to maintain LDL-cholesterol reduction for up to of dietary fiber through food sources and/or fiber supplements. six months.19 Be sure to recommend a fiber that complements your patient’s health goals. Encourage your patients to talk with their doctor about whether taking a fiber supplement as 18 Anderson JW, et al. Am J Clin Nutr. 2000;71:472-479. 19 Anderson JW, et al. Am J Clin Nutr. 2000;71:1433–1438. part of a is right for them. 20 Sierra M, et al. Eur J Clin Nutr. 2001;55:235-243. 21 Anderson JW, et al. Am J Clin Nutr. 1999;70:466-473. 22 Rodriguez-Moran M, et al. J Complications. 1998;12:273-278. 23 Sierra M, et al. Eur J Clin Nutr. 2002;56:830-842. 24 Ziai SA, et al. J Ethnopharmacol. 2005;102:202-207.