Go With Your Gut: The Facts on Fiber

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approved QUIZ 2: PAGE 2 Go With Your Gut: The Facts on Fiber By Adriana Soto-Vaca, PhD, and Megan Nechanicky, MS, RD Ever wonder why fiber is so great for your digestion?

1 approved QUIZ 2: PAGE 2 Go With Your Gut: The Facts on Fiber By Adriana Soto-Vaca, PhD, and Megan Nechanicky, MS, RD Ever wonder why fiber is so great for your digestion? Get the facts, and find out how to add more fiber to your clients diets. Most of us know the basics on fiber: It helps us stay regular, and if things aren t as regular as usual, we try to eat more foods like bran cereals and prunes. But there is far more to know about fiber, especially in relation to health and wellness. What exactly is fiber? Why is it so good for our digestive systems? Can it fend off disease? How much should we consume? How does the recommended intake compare with how much the typical American eats? Fortunately, the abundant health benefits of fiber have been thoroughly investigated, and emerging areas of research are yielding a host of insights that are useful to fitness professionals. Read on to get your fill on fiber, find out how much fiber you and your clients need, and learn even more from our translation of some of the latest science. (See Tables 1, 2 and 3, respectively, for grams of dietary fiber in standard portions of some common foods; easy swaps to help you choose foods that provide more dietary fiber; and how much fiber we need in our diets, by age and gender, versus how much we re getting on average.) What Is Fiber? Dietary fibers are parts of plants (storage and cell wall polysaccharides) that the human body s digestive enzymes 1 IDEA Food and Nutrition Tips November December 2015

2 Fiber s documented health benefits range from satiety and weight control to reduction of cardiovascular disease risk. November December 2015 IDEA Food and Nutrition Tips 15

Table 1: Dietary Fiber FOOD SOURCES FOOD GRAINS high-fiber bran ready-to-eat cereal oat bran muffin STANDARD PORTION SIZE 1 /3 ¾ cup ¾ 1 cup DIETARY FIBER IN STANDARD PORTION (GRAMS) 9 1 3 Fiber can

whole-wheat spaghetti, cooked quinoa 1 small 3 3 BEANS/LEGUMES navy beans, cooked chickpeas, canned lentils, cooked black beans, cooked white beans, cooked kidney beans, all types, cooked FRUITS

3 Table 1: Dietary Fiber FOOD SOURCES FOOD GRAINS high-fiber bran ready-to-eat cereal oat bran muffin STANDARD PORTION SIZE 1 /3 ¾ cup ¾ 1 cup DIETARY FIBER IN STANDARD PORTION (GRAMS) Fiber can occur naturally in plant-based foods like beans and whole grains, or it can be isolated from plants and then added to foods. whole-wheat spaghetti, cooked quinoa 1 small 3 3 BEANS/LEGUMES navy beans, cooked chickpeas, canned lentils, cooked black beans, cooked white beans, cooked kidney beans, all types, cooked FRUITS apple, with skin pear banana avocado figs, dried 1 medium 1 medium 1 medium ¼ cup VEGETABLES green peas, cooked, from fresh or frozen 3 mixed vegetables, cooked, from frozen collard greens, cooked sweet potato, baked in skin 1 medium Source: Adapted from U.S. Department of Agriculture, Agricultural Research Service, Nutrient Data Laboratory USDA National Nutrient Database for Standard Reference, Release 27. Accessed Aug. 25, IDEA Food and Nutrition Tips November December 2015

4 BLOOD GLUCOSE LEVELS Research shows that people who eat high-fiber diets are less likely to have diabetes. Studies also show that higher-fiber diets may play a significant role in preventing diabetes or in halting the progression of prediabetes to diabetes (Anderson et al. 2009). Current evidence suggests that a daily diet with g of fiber results in lower blood glucose levels than a low-fiber diet does (Marlett et al. 2002). This may be relevant to people who need to manage their blood glucose. Health Benefits for the Gut and Beyond Emerging research is revealing specific ways that fiber improves gastrointestinal health and promotes changes in the gut (including stomach, small intestine and large intestine) that can improve our overall well-being. Laxation and regularity are the most widely recognized benefits of consumcannot break down. Broadly, they fall into two categories: soluble fibers, which dissolve in water, and insoluble fibers, which do not dissolve in water. For example, oat bran contains mostly soluble fiber, while wheat bran has mainly insoluble fiber (Marlett et al. 2002). Soluble fibers typically form a gel in water and/or are fermented in the colon (Slavin 2013). Fiber can occur naturally in plant-based foods like beans and whole grains, or it can be isolated from plants and then added to foods (USDA & HHS 2010). Health Benefits of Fiber Fiber s documented health benefits range from satiety and weight control to reduction of cardiovascular disease risk. The Institute of Medicine identifies three primary health benefits of fiber: reduced risk of coronary heart disease, assistance in the maintenance of blood glucose levels and improved laxation (IOM 2005). CORONARY HEART DISEASE Studies have associated high intakes of dietary fiber and the consumption of whole grains with a reduced risk for coronary heart disease. Research indi- cates that this happens because fiber can help to lower levels of LDL ( bad cholesterol ) in the blood (Slavin 2013). Fiber has also been shown to reduce other risk factors associated with CHD, including obesity, blood pressure and elevated cholesterol. Table 2: Getting More Fiber THROUGHOUT THE DAY Recommend these easy swaps to help your clients get more fiber in their diets. AT SWAP FOR breakfast 1 glass of apple juice 1 whole apple 0 g fiber 6 g fiber lunch 2 slices white sandwich bread 2 slices whole-wheat sandwich bread 1.5 g fiber g fiber snack time puffed-rice snack bar Fiber One Oats & Chocolate Chewy Bar 0 g fiber 9 g fiber dinner 1 cup chili (no beans) 1 cup chili with beans 1 g fiber 8 g fiber Source: Adapted from U.S. Department of Agriculture, Agricultural Research Service, Nutrient Data Laboratory USDA National Nutrient Database for Standard Reference, Release 27. Accessed Aug. 25, Great Day Granola Three cereals, three nuts and honey star in this granola, which makes a satisfying on-the-go breakfast. C quick-cooking or old-fashioned oats 3 C Golden Grahams cereal 3 C Fiber One original bran cereal 1 C chopped walnuts 1 C sliced almonds 1 C sunflower nuts 1 C packed brown sugar ½ C canola or vegetable oil ½ C honey ½ C water ½ t vanilla ½ t almond extract Key: C = cup; t = teaspoon Heat oven to 250 F. Spray 2 (15 x 10 x 1 ) pans with cooking spray. In large bowl, mix oats, both cereals, walnuts, almonds and sunflower nuts. In 2-quart saucepan, heat brown sugar, oil, honey and water over medium-high heat 3 5 minutes, stirring constantly, until brown sugar is melted. Remove from heat. Stir in vanilla and almond extract. Pour over cereal mixture; stir until well coated. Spread mixture evenly in pans. Bake 1 hour, rearranging pans once halfway through baking. Cool completely in pans, about 1 hour. Break into pieces. Store in tightly covered container. Serve as breakfast cereal, as snack or as topping for ice cream, yogurt or fresh fruit. Makes 32 servings. Per serving: 220 calories; 10 g fat; no cholesterol; 55 mg sodium; 28 g carbohydrate; 5 g dietary fiber; 13 g sugars; g protein. Source: Recipe and picture courtesy of General Mills. ing enough fiber. Combining a high-fiber diet with adequate fluid intake and adequate exercise (such as walking or running) helps maintain regularity and may prevent constipation (ACG 2010). Fiber assists in maintaining normal bowel movements by increasing the weight and size of stools; it also promotes a softer stool consistency. Stool weight and size can increase for several reasons: the presence of fiber itself, the water absorbed by the fiber and the rising quantity of stool November December 2015 IDEA Food and Nutrition Tips 17

5 18 IDEA Food and Nutrition Tips November December 2015 Fermentable fibers are found in foods like wheat, oats, barley, chicory root, artichokes, peaches, apples and carrots.

6 Fiber One Green Smoothies Add more fiber the delicious way with these green smoothies and Fiber One cereal. 1 box (9 oz) Green Giant frozen chopped spinach 1 container (6 oz) Yoplait Original 99% Fat Free Key lime pie or French vanilla yogurt 2 medium kiwi fruit, peeled, quartered ½ C ice cubes ½ C fat-free (skim) milk 2 T Fiber One original bran cereal Key: C = cup; oz = ounce; T = tablespoon Microwave spinach as directed on box. Rinse with cold water until cooled. Drain, squeezing out as much liquid as possible. In blender, place 1 /3 cup of cooked spinach and remaining ingredients (cover and refrigerate remaining spinach for another use). Cover; blend on high speed about 30 seconds or until smooth. Pour into two glasses. Serve immediately. Serves two. Per serving: 190 calories; 2 g fat; 5 mg cholesterol; 150 mg sodium; 36 g carbohydrate; 6 g dietary fiber; 23 g sugars; 8 g protein. Source: Image and recipe courtesy of General Mills. Table 3: Average Dietary Fiber Intake (GRAMS/DAY) IN MALES AND FEMALES IN THE UNITED STATES DIETARY REFERENCE INTAKE GROUPS BY AGE microbes that result from fermentation of fiber in the intestine (Marlett et al. 2002). Cereal fibers, especially wheat bran, are considered most effective in increasing stool weight (Slavin 2013). Fiber fermentation may be key to gut health. As fibers especially soluble fibers get fermented by certain gut bacteria, they are converted into acids, including short-chain fatty acids (SCFAs), and gas. This makes the environment acidic, discouraging the growth of pathogens and putrefactive bacteria. SCFAs also promote the growth of certain intestinal cells, thickening the intestinal walls and possibly reducing the risk of bacteria migrating out of their physiologic boundaries (Meyer 2015). Fermentable fibers are found in foods like wheat, oats, barley, chicory root, artichokes, peaches, apples and carrots. FIBER AND THE MICROBIOTA Emerging research has shown that fiber has a strong influence on the diversity and composition of the GI microbiota the microorganisms that live in the gastrointestinal tract. This diversity and composition can play an important role in overall physical well-being. Microorganisms in the gut interact with each other and with the human body, influencing health and disease MALES MALES MALES FEMALES FEMALES FEMALES Average Adequate Above- Average Adequate Above- Fiber Intake Intake Adequate Fiber Intake Intake Adequate (g/day) (g/day) Intake (%) (g/day) (g/day) Intake (%) 1 3 years < <3 8 years < < years < < years < < years < < years < years years and over USDA 2015a. (Clemente 2012). A healthy human s GI microbiota typically contains several hundred species, which account for trillions of microorganisms. Overall, high-fiber plant-based diets are associated with a more diverse GI microbiota and higher production of SCFAs than are diets low in fiber (Simpson & Campbell 2015). Certain fermentable fibers can act as prebiotics. A dietary prebiotic is a selectively fermented ingredient that results in specific changes in the composition and/or activity of the GI microbiota, thus conferring benefit(s) upon host health (Gibson et al. 2010). In other words, prebiotics selectively stimulate the growth and/or activity of certain beneficial bacteria. Suggested benefits of consuming prebiotics include reducing the prevalence and duration of diarrhea, enhancing the uptake of minerals like calcium and magnesium, and protecting against chronic diseases like colon cancer and heart disease (Slavin 2013; Anderson et al. 2009). Most prebiotic fibers are oligosaccharides complex carbohydrates made up of chains of simple sugars that get fermented by the microbiota in the colon (Slavin 2013). Inulin (also known as fructooligosaccharides, or FOS), the most widely studied prebiotic fiber, has beneficial effects at relatively low doses (5 g per day). Inulin is a fiber found in many plants, like garlic, onions, asparagus, chicory, artichokes, bananas, wheat and leeks (Gibson et al. 2010). It can be readily extracted from chicory root and incorporated into products like snack bars and breakfast cereal. Other prebiotic fibers include galactooligosaccharides from milk, polydextrose and soluble corn fiber (Slavin 2013; Meyer 2015). REDUCED COLON CANCER RISK Early evidence from studies of dietary patterns and health outcomes around the world found that populations with higher dietary fiber intakes had a reduced risk for developing colon cancer (Marlett November December 2015 IDEA Food and Nutrition Tips 19

7 20 IDEA Food and Nutrition Tips November December 2015 Whole-grain foods include oatmeal, ready-to-eat cereal, oat-based cereal bars and whole-grain bread.

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8 Take the Quiz or mail the quiz on page 2. Black Bean Dip Veggie Dippers 1 C Fiber One original bran cereal 1 large tomato, chopped (1 C) 1 can (15 oz) Progresso black beans, drained, rinsed ¼ C water 2 T lime juice ¼ C chopped green onions ( medium) 1 small clove garlic, coarsely chopped ½ t salt ½ t ground cumin ½ t chili powder ¼ to ½ t hot pepper sauce 2 T chopped fresh cilantro additional chopped cilantro, if desired 3 C assorted cut-up fresh vegetables (such as baby carrots, bell pepper strips, cauliflower florets) Key: C = cup; oz = ounce; T = tablespoon; t = teaspoon In food processor, process cereal until slightly crushed. Add of the chopped tomato, and the beans, water, lime juice, onions, garlic, salt, cumin, chili powder and hot pepper sauce to cereal. Cover; process until almost smooth. In 1-quart microwavable serving bowl, place bean mixture. Microwave on high 2 3 minutes or until hot. Stir in the reserved tomato and 2 T cilantro. Sprinkle with additional cilantro. Serve with fresh vegetables for dipping. Makes nine servings (¼ cup dip and 1 /3 cup vegetables each). Per serving: 80 calories; 0.5 g fat; 330 mg sodium; 16 g carbohydrate; 6 g dietary fiber; g sugars; 3 g protein. Source: Recipe and image courtesy of General Mills. et al. 2002; Meyer 2015). A study two decades ago estimated that colorectal cancer risk in the United States could drop by 31% if people increased their fiber intake by an average of 13 g per day (Howe et al. 1992). However, intervention studies and more recent epidemiological evidence have been mixed and cannot support this hypothesis, so further research is needed (Marlett et al. 2002; Anderson et al. 2009). Much Fiber Do You and Your Clients Need? When the Institutes of Medicine established the Dietary Reference Intake system, there was not enough evidence to create a Recommended Dietary Allowance (commonly known as RDA) for fiber. An Adequate Intake, or AI, for fiber was determined based on the amount needed to reach the lowest risk for coronary heart disease. The DRI recommends 1 g of dietary fiber per 1,000 calories. For adult women eating a 2,000-calorie-per-day diet, that would be 28 g of fiber; for adult men eating a 2,600-calorie-per-day diet, the amount would be 36 g of fiber (USDA & HHS 2010). Are Americans Eating Enough Fiber? Although the health benefits of fiber are widely understood, 9 out of 10 Americans are not getting enough fiber in their diets: Only 5% of adults and less than 1% of children and teens meet their daily fiber recommendations (see Table 3). In the United States, the average fiber intake is 15 g per day, less than half the recommended amount (IOM 2005). Women over 50 years of age get the most fiber in their diets, but only 17% of them meet the recommendation (USDA 2015a). FOODS WITH FIBER With so many Americans missing out on the numerous benefits of fiber, personal trainers can play a key role in knowing and recommending food sources of fiber (see Tables 1 and 2). To get more fiber into your clients diets, recommend that they consume more whole grains, fruits, vegetables and legumes (USDA 2015b). Whole-grain foods include oatmeal, ready-to-eat cereal, oat-based cereal bars and whole-grain bread. Other sources of fiber include fruit such as bananas, apples and strawberries, and legumes and vegetables like peas, lentils and spinach. UNDERSTANDING FOOD LABELS A product can be labeled a good source of fiber if it has at least 2.5 g of fiber per serving. It can be labeled an excellent source of fiber if it has 5 g or more of fiber per serving. n Adriana Soto-Vaca, PhD, and Megan Nechanicky, MS, RD, are senior nutrition scientists with the General Mills Bell Institute of Health and Nutrition. Soto- Vaca holds an MS and a PhD in food science from Louisiana State University, with a focus on foods for health. Nechanicky is a registered dietitian; she completed a dual master s program in exercise physiology and nutrition at San Diego State University by IDEA Health & Fitness Inc. All rights reserved. Reproduction without permission is strictly prohibited. References ACG (American College of Gastroenterology) GI health and disease. Accessed July 23, patients.gi.org. Anderson, J.W., et al Health benefits of dietary fiber. Nutrition Reviews, 67 (), Clemente, J.C., et al The impact of the gut microbiota on human health: An integrative view. Cell, 18 (6), Gibson, G.R., et al Dietary prebiotics: current status and new definition. Food Science & Technology Bulletin: Functional Foods, 7 (1), Howe, G.R., et al Dietary intake of fiber and decreased risk of cancers of the colon and rectum: Evidence from the combined analysis of 13 case-control studies. Journal of the National Cancer Institute, 8 (2), IOM (U.S. Institute of Medicine) Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids. Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. Washington, DC: National Academies Press. Marlett, J.A., et al Position of the American Dietetic Association: Health implications of dietary fiber. Journal of the American Dietetic Association, 102 (7), Meyer, D Health benefits of prebiotic fibers. In J. Henry (Ed.), Advances in Food and Nutrition Research (Vol. 7, pp. 7 91). Waltham, MA: Academic Press. Simpson, H.L., & Campbell, B.J Review article: Dietary fibre-microbiota interactions. Alimentary Pharmacology & Therapeutics, 2 (2), Slavin, J Fiber and prebiotics: Mechanisms and health benefits. Nutrients, 5 (), USDA (U.S. Department of Agriculture). 2015a. Individuals 1 year and over (excluding breast-fed children and pregnant or lactating females), dietary intake data. What We Eat in America, NHANES Scientific Report of the 2015 Dietary Guidelines Advisory Committee. USDA. 2015b. What We Eat in America, NHANES (ages 2+). Scientific Report of the 2015 Dietary Guidelines Advisory Committee, Part E. Section 2: Supplementary Documentation to the 2015 DGAC Report. USDA & HHS (U.S. Department of Agriculture & Department of Health and Human Services) Dietary Guidelines for Americans (7th ed.). Washington, DC: U.S. Government Printing Office. November December 2015 IDEA Food and Nutrition Tips 21

Fiber and Healthy Hearts

Fiber and Healthy Hearts Fiber is a carbohydrate that our bodies do not digest. This means it provides no calories. Fiber goes through our digestive tract mostly unchanged, which provides health benefits