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Home , Dietary fiber, Mucilage

Dietary Fact Sheet No. 9.333 and Series|Health

by J. Clifford, K. Niebaum, L. Bellows (3/15) Can high-fiber diets really do all they Listed below in Table 1 are dietary sources Quick Facts claim to do? Studies have looked at the of soluble and insoluble fiber: relationship between high-fiber diets and • Fiber may be beneficial many diseases, including colon , Table 1: Sources of . in treating or preventing coronary heart disease and . Soluble Fiber Insoluble Fiber , and Proven benefits of a high-fiber include whole grains . prevention and treatment of constipation, • -soluble fiber helps hemorrhoids and diverticulosis. In addition, fruits certain types of fiber help decrease blood decrease blood vegetables beans cholesterol levels. levels. • containing dietary fiber What Is Dietary Fiber? Benefits of Fiber include fruits, vegetables, nuts Dietary fiber comes from the portion of Digestion and grains. Insoluble fiber binds water as it passes that is not digested in the intestinal through the digestive tract, making • Include a variety of high-fiber tract. Part of it, however, may be broken stools softer and bulkier. Therefore, fiber, foods in the diet. down by in the lower gut. especially that found in Different types of plants vary in products, is helpful in the treatment and their amount and kind of fiber. Fiber prevention of constipation, hemorrhoids includes , gum, , , and diverticulosis. Diverticula are pouches and . of the intestinal wall that can become Soluble Fiber inflamed and painful. This inflammatory Pectin and gum are water-soluble condition is called diverticulosis. In the found inside cells. They slow past, a low-fiber diet was prescribed for this the passage of food through the intestines condition. It is now known that a high- but do nothing to increase fecal bulk. fiber diet gives better results at preventing Soluble fibers have been shown to decrease once the inflammation has cholesterol and lower blood . Beans, subsided. oat bran, and vegetables contain Cholesterol water-soluble fiber. Low blood cholesterol levels (below Insoluble Fiber 200 mg/dl.) have been associated with a Fibers in cell walls are water insoluble. reduced risk of coronary heart disease. The These include cellulose, hemicellulose and body uses cholesterol in the production lignin. Such fibers increase fecal bulk and of bile acids some of which are excreted speed up the passage of food through daily. The consumption of water-soluble © Colorado State University the digestive tract. bran and whole fiber binds to bile acids, suggesting that a Extension. 12/98. Revised 7/15 grains contain the highest amounts of high-fiber diet may result in an increased extension.colostate.edu insoluble fiber, but vegetables and beans excretion of cholesterol. Some types of also are good sources. fiber, however, appear to have a greater effect than others. The fiber found in rolled is more effective in lowering blood cholesterol levels than the fiber found in wheat. Pectin has a similar effect in lowering the amount of cholesterol in the *July, 2015, reviewed and revised by Colorado State University Jessica Clifford, Research Associate and Extension blood. Pectin is found in some fruits such as Specialist and K. Maloney, graduate student in the Dept of , , and citrus fruits. Food Science . Original publication by Kate Tophman, CSU food science and human nutrition graduate Cancer student. 12/2010 Table 2:Dietary fiber content of foods High-fiber diets may also reduce The removal of , peels or Serving size Fiber(grams) the risk of developing some types of hulls also reduces fiber content. Whole , ,grains cancer, especially colon cancer. This idea tomatoes have more fiber than peeled White 1 slice 0.6 is based on information that insoluble tomatoes, which have more than Whole grain bread 1 slice 1.7 fiber increases the rate at which wastes juice. Likewise, whole wheat bread 100% All Bran 1/2 cup 8.8 are removed from the body. This means contains more fiber than . Corn Flakes 1 cup 0.7 the body may have less exposure to toxic Table 2 lists the dietary fiber content of Shredded Wheat 2 biscuits 5.5 substances produced during digestion. some common foods. , cooked 1 cup 4.0 , brown, cooked 1/2 cup 1.75 While many studies have shown an Functional Fiber Rice, white, cooked 1/2 cup 0.3 association between increased fiber Functional fiber is a newer term that Fruit (fresh unless 26 intake and reduced prevalence of colon includes foods that consist of isolated, otherwise noted) cancer, the mechanisms of how fiber nondigestible that , with skin 1 large 3.3 consumption may reduce cancer risk are have beneficial physiological effects 1 0.7 still unknown. in humans. Cellulose, , beta 1 3.1 Weight loss , gums, , oligofructose, Blackberries 1 cup 7.6 High-fiber diets may be useful for fructoligosaccharides, lignin, , Dates 5 3.3 10 n/a people who wish to lose weight. Fiber , and resistant are forms , pink and 1/2 2.0 itself has no calories, yet provides a “full” of functional fiber when added to foods. red feeling because of its water-absorbing Inulin or inulin is one functional Grapefruit, white 1/2 1.3 ability. For example, an apple that fiber that is receiving more attention, as it Melon, 1 cup 1.4 contains fiber is more filling than a half is being added into many food products. Nectarine 1 2.3 cup of apple juice that contains about the While 10 grams per day of chicory inulin 1 small 3.1 same calories but no fiber. Foods high in has been shown to be well-tolerated 1 1.5 fiber often require more chewing, thus in healthy adults, higher intakes have 1 medium 5.1 it takes more time to eat, so a person is been associated with gas and . 1 cup 2.2 unable to eat a large number of calories in Therefore, it is recommended to consume 1 small 0.9 a short amount of time. functional fiber in moderation as a part of , dried 5 3.0 a balanced diet. 1/4 cup 1.4 Diabetes and 1 cup 3.3 Additionally, recent research suggests that a high-fiber diet rich in whole grains Vegetables How Much Fiber? Beans, baked, canned, 1 cup 10.4 is associated with a reduced risk for plain developing and obesity. The average American consumes Beans, green, cooked 1 cup 4.0 Greater consumption of fiber found in 14 grams of dietary fiber a day, which is Beets, canned 1 cup 2.9 whole grains, compared to , considerably less than the recommended , raw 1 cup 2.3 has been shown to modestly reduce level. The 2010 Dietary Guidelines for , raw 1 cup 1.6 Americans recommends 14 grams of , raw 1 cup 3.1 and improve , raw 1 cup 2.5 sensitivity, resulting in an decreased fiber per 1000 calories consumed. So, if , raw 1 cup 1.9 risk for developing type 2 diabetes and you consume a 2,500 calorie diet, you Corn, yellow, cooked 1 cup 3.9 obesity. To increase your fiber intake, it should eat approximately 35 grams of , cooked 1 cup 15.6 is recommended by the 2010 Dietary fiber per day. Also, fiber intake may vary , romaine, raw 1 cup 1.2 Guidelines for Americans to make at least depending on age and gender. Lettuce, iceberg, raw 1 cup 0.7 half of grains consumed whole grains for While the 2010 Dietary Guidelines , boiled 1 cup 4.5 optimal health. for Americans serves as a general Peas, split 1 cup 16.3 guide to healthy eating, the Dietary , baked, fresh 1/2 potato 2.3 Reference Intakes (DRIs) provide standard , cooked 1/2 potato 3.9 without skin Sources of Fiber recommended amounts for . Tomato, red, ripe 1 tomato 1.5 Foods In 2002, the Food and Nutrition Board , cooked 1 cup 5.7 Dietary fiber is found only in plant of the National Academy of Sciences squash 1/2 cup n/a foods: fruits, vegetables, nuts and grains. Research Council issued DRIs for fiber Other foods Meat, milk and eggs do not contain fiber. (see Table 3). Previously, no national Meat, milk, eggs 0 The form of food may or may not affect standardized recommendation existed. (24 nuts) 1 oz. 3.3 its fiber content. Canned and frozen fruits The new DRIs represent desirable intake , dry roasted 1 oz. 2.3 and vegetables contain just as much fiber (approx. 28) levels established using the most recent , English (14 1 oz. 1.9 as raw ones. Other types of processing, scientific evidence available. halves) though, may reduce fiber content. Drying Although fiber is important, it is and crushing, for example, can destroy just one part of a balanced diet, and the water-holding qualities of fiber. For like all foods, should be consumed in this reason, dried fruit may have less fiber moderation It is possible that too much than raw fruit. fiber may reduce the amount of , , , and that in fruits, vegetables and grain products is absorbed from foods. Deficiencies of Table 3: Dietary Reference Intakes (DRI) for Fiber. that contain fiber, particularly soluble these nutrients could result if the amount Age g/day Fiber fiber, may reduce the risk of coronary of fiber in the diet is excessive, especially heart disease.” In order to make a health in young children. Children claim about fiber and coronary heart Tips for increasing fiber 1-3 years 19 disease, the food must contain at least 0.6 For many people, meeting the DRI for 4-8 years 25 g of soluble fiber per reference amount. fiber may require changes in their eating Males The soluble fiber content must be listed habits. Consider the following tips when and cannot be added or fortified. A 9-13 years 31 increasing fiber in your diet: product containing a for • Aim for at least 3servings of whole 14-18 years 38 fiber and coronary heart disease must grains a day, such as oatmeal for 19-50 years 38 also meet the definitions of a low fat, low breakfast, whole wheat bread at 51+ years 30 in saturated fat and low in cholesterol lunch, and with dinner. Females product. • Try adding more to your A statement such as “made with 9-13 years 26 diet. Add black beans to a or oat bran” or “high in oat bran” implies chick peas to a salad. 14-18 years 26 that a product contains a considerable • Increase your daily fruit and 19-50 years 25 amount of the . Claims that imply intake. Aim for 5 servings 51+ years 21 a product contains a particular amount total per day. Choose whole fruits Pregnancy 10 of fiber can be made only if the food more often than dried fruit or fruit actually meets the definition for “high <18 years 28 juices. Cut up veggies for an easy fiber” or “good source of fiber,” whichever snack throughout the day. Make 18+ years 28 is appropriate. gradual increases. If you are not used Lactation The following terms describe products to eating high fiber foods regularly, <18 years 29 that can help increase fiber intake: changes should be made gradually 18+ years 29 • High fiber: 5 g or more per serving to avoid problems with gas and • Good source of fiber: 2.5 g to 4.9 g . Drink plenty of water to per serving minimize intestinal gas. If problems Figure1: Showing Fiber Listed in Grams • More or added fiber: At least 2.5 g with gas continue to be an issue, more per serving than the reference gas-reducing over-the-counter and food prescription drugs are available. Supplements • Anyone with a chronic disease should Fiber supplements are sold in a consult a physician before greatly variety of forms from bran tablets to altering a diet. purified cellulose to powdered psyllium. Many sold as stool softeners Food Labeling of Fiber are actually fiber supplements. Fiber’s role in the diet is still being investigated. Nutrition Facts Label It appears that the various types of Nutrients required on the Nutrition fiber have different roles in the body. Facts Label reflect current public health Furthermore, fiber may interact with recommendations. The Nutrition Facts prescription medications. If you are taking Label list a Daily Reference Value (DRV) for prescription medications, check with your specific nutrients, including fiber. The DRV doctor before taking a fiber supplement. for fiber is 25 grams per day based on a 2,000 calorie diet, or 30 grams per day based on a 2,500 calorie diet. The fiber Summary content of a food is listed in grams and as It is recommended to meet dietary a percentage of the daily value. fiber recommendations by eating a Figure 1 shows a food nutrition label. It variety of fiber-rich foods. This is the best tells you the product provides 3g of fiber way to receive the maximum benefits in a half cup serving. The percent Daily from each type of fiber present in foods, Value for one serving is 12 percent, or 12 and obtain necessary nutrients. percent of DRV of 25 grams based on a 2,000 calorie diet. Health Claims Specific health claims can be made for food products that meet specific requirements. For example: “Diets low in saturated fat and cholesterol and rich References

• Aune, D., Chan, D., Lau, R., Vieira, R., Greenwood, D., Kampman, E., & Norat, T. (2011). Dietary Fibre, Whole Grains, And Risk Of : Systematic Review And Dose-response Meta-analysis Of Prospective Studies. BMJ, 343, D6617-D6617. • Bonnema, A., Kolberg, L., Thomas, W., & Slavin, J. (2010). Gastrointestinal Tolerance of Chicory Inulin Products. Journal of the American Dietetic Association, 110(6), 865-868. • Cho, S., Qi L., Fahey, G., & Klurfeld, D. (2013). Consumption of fiber, mixtures of whole grains and bran, and whole grains and risk reduction type 2 diabetes, obesity, and . The American Journal of Clinical Nutrition, 594-619. • Food Labeling Guide. (2013). Washington, DC: U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition. • Institute of Medicine. (2005). Dietary Reference Intakes for Energy, , Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). National Academy Press p. 265-334. • Kaczmarczyk, M., Miller, M., & Freund, G. (2012). The health benefits of dietary fiber: Beyond the usual suspects of type 2 diabetes mellitus, cardiovascular disease and colon cancer. , 61(8), 1058-1066. • Lattimer, J., & Haub, M. (2010). Effects of Dietary Fiber and Its Components on Metabolic Health. Nutrients, 2(12), 1266-1289. • Tucker, L., & Thomas, K. (2009). Increasing Total Fiber Intake Reduces Risk of Weight and Fat Gains in Women. Journal of Nutrition, 576- 581

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