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Nutrition Science and Policy January 2006: 31–38 Dietary Reference Intakes: Implications for Fiber Labeling and Consumption: A Summary of the International Life Sciences Institute North America Fiber Workshop, June 1-2, 2004, Washington, DC Julie R. Jones, PhD, David M. Lineback, PhD, and Marci J. Levine, PhD © 2006 International Life Sciences Institute doi: 10.1301/nr.2006.jan.31–38 INTRODUCTION Since the recognition of the importance of dietary fiber for good nutrition, multiple definitions of the term Dr. Jones is with the Department of Family, Consumer and Nutritional Sciences, College of St. Catherine, Minneapolis, Minnesota; Dr. Lineback is with the Joint Institute for Food Safety & Applied Nutrition, University of Maryland, College Park, Maryland; Dr. Levine is with the North American Branch of the International Life Sciences Institute (ILSI NA), Washington, DC; Drs. Jones and Lineback are scientific advisors for the ILSI NA Technical Committee on Carbohydrates. Please address all correspondence to: Dr. Marci Levine, ILSI North America, One Thomas Circle NW, Ninth Floor, Washington, DC 20005; Phone: 202-6590074; Fax: 202-659-3859; E-mail: [email protected]. Nutrition Reviews姞, Vol. 64, No. 1 “fiber” have been developed. The Institute of Medicine (IOM) recently defined dietary fiber1 at the request of the US Food and Drug Administration (FDA). In response to their definition, the North American branch of the International Life Sciences Institute (ILSI NA) Technical Committee on Carbohydrates held a workshop entitled “Dietary Reference Intakes: Implications for Fiber Labeling and Consumption,” June 1-2, 2004 in Washington, DC. Participants discussed the merits and limitations of the IOM definition compared with other definitions. In attendance were representatives from industry, academia, US and Canadian government agencies, and scientific associations. HISTORY OF DEFINITIONS OF FIBER The term “dietary fiber” was originally coined by Hipsley in 1953.2 In 1972, Trowell et al.3 proposed a definition of dietary fiber as “the skeletal remains of plant cells that are resistant to digestion (hydrolysis) by enzymes of man.” Between 1972 and 1976, a series of hypotheses were advanced relating the consumption of dietary fiber to various health states, including prevention of constipation, diverticular disease, hiatus hernia, appendicitis, varicose veins, piles (hemorrhoids), diabetes, obesity, coronary heart disease, cancer of the large bowel, and gallstones, with implications in duodenal ulcers, breast cancer, and blood clotting. By 1976, it was learned that other plant components not in the plant cell wall, e.g., mucilages, gums, and pectins, were also resistant to digestion. Therefore, Trowell’s definition was revised to “dietary fiber is the endogenous components of the plant polysaccharides and lignin which are resistant to hydrolysis by digestive enzymes of man.”4 In the late 1970s, international surveys showed that the 1976 Trowell definition was the proper basis for a working definition of dietary fiber and related methods of determination (analysis).5,6 By 1981, the dietary fiber definitions proposed in the 31 Downloaded from http://nutritionreviews.oxfordjournals.org/ by guest on September 18, 2016 Multiple definitions of dietary fiber have been developed and are in use around the world. The definitions vary as to which substances are considered to be fibers, the analytical methods utilized to identify and measure these fibers, and whether physiological criteria are part of the definition. A workshop entitled “Dietary Reference Intakes: Implications for Fiber Labeling and Consumption” was held by the International Life Sciences Institute North America Technical Committee on Carbohydrates to review the fiber definitions recently published by the Institute of Medicine (IOM) of the National Academies. Presentations and facilitated discussions reviewed the rationale for the IOM definitions of dietary fiber, functional fiber, and total fiber in light of evolving nutritional science. Also discussed were potential analytical, regulatory, and consumer issues involved if the US Food and Drug Administration and/or Health Canada were to implement the IOM’s recommendations. Issues, concerns, and questions to be addressed are summarized here. Dietary fiber is the edible parts of plants or analogous carbohydrates that are resistant to digestion and absorption in the human small intestine with complete or partial fermentation in the large intestine. Dietary fiber includes polysaccharides, oligosaccharides, lignin, and associated plant substances. Dietary fibers promote beneficial physiological effects including laxation, and/or blood cholesterol attenuation, and/or blood glucose attenuation.12 32 This definition reflects the desire to describe fiber chemically, structurally, and physiologically. It builds on prior knowledge of scientific and regulatory efforts, while allowing for the incorporation of potential future discoveries. At about the same time the AACC was developing a definition for fiber, the IOM was developing new dietary reference intakes (DRIs). As part of the DRI process, the Panel on the Definition of Dietary Fiber was formed as part of the DRI review of macronutrients to propose a definition(s) for dietary fiber and provide a rationale for its definition(s).1,13 Part of developing a definition involves studying existing definitions and identifying how they differ from one another. The IOM panel expressed the desire to move from the analytically based de facto definition to one that recognizes numerous physiological effects of fiber.13 The report13 from the IOM fiber panel discusses which substances should be called dietary fiber, particularly since some animal sources (e.g., chitosan) could be determined by current analytical methods to be dietary fiber. Another issue was the physical state of the fiber, or whether it should remain intact. Further, the report of the IOM fiber panel discussed whether a dietary fiber needed to exert a particular health benefit. It stated that, without a formal definition, compounds that may have physiological fiber-like benefits but are not considered to be dietary fiber by current AOAC methods of analysis could not be called dietary fiber. In contrast, materials that are determined to be dietary fiber by these methods but do not have beneficial physiological effects can still be called dietary fiber. The IOM panel recognized that non-digestible carbohydrates are often isolated to concentrate a desirable fiber component or benefit of the source material, and that this isolated fiber could be added to products to enhance health benefits. Therefore, the IOM fiber panel proposed that isolated fiber components should be considered separately and have proven physiological benefits in humans, and proposed the following definitions: ● Dietary fiber consists of non-digestible carbohydrates and lignin that are intrinsic and intact in plants. ● Added fiber consists of isolated, non-digestible carbohydrates that have beneficial physiological effects in humans. ● Total fiber is the sum of dietary fiber and added fiber.13 After receipt of comments on the IOM fiber panel’s recommendations and further deliberations on the definitions, the DRI Panel on Macronutrients revised the definition by changing “added” to “functional,” with the following result: ● Dietary fiber consists of non-digestible carbohydrates and lignin that are intrinsic and intact in plants. Nutrition Reviews姞, Vol. 64, No. 1 Downloaded from http://nutritionreviews.oxfordjournals.org/ by guest on September 18, 2016 early 1970s evolved to the following: “dietary fiber consists of the remnants of edible plant cells, polysaccharides, lignin, and associated substances resistant to digestion (hydrolysis) by the alimentary enzymes of humans.”7,8 This definition included cellulose, hemicelluloses, lignin, gums, modified celluloses, mucilages, oligosaccharides, pectin, and associated minor substances such as waxes, cutin, and suberin. In 1981, the Association of Official Analytical Chemists (AOAC) held an international workshop at which they reached consensus on this definition and resolved to move toward practical applications. The AOAC determined that methods of analyzing dietary fiber should be rugged, able to simulate the human digestive behavior designated in the definition, and that competent laboratories should be able to analyze all foods.6 The enzyme-gravimetric method called “Official Method of Analysis 985.29”9 does capture most of the substances that the working consensus definition7,8 prescribed as total dietary fiber.7 Other AOAC methods have since been developed to analyze, for example, insoluble dietary fiber (AOAC Method 991.42) and soluble dietary fiber (AOAC Method 993.19). However, an interesting phenomenon occurred in which the most widely used method for measuring dietary fiber, AOAC Method 985.29, began to be used as the definition of fiber itself by the FDA and by many other countries worldwide.10 This is exemplified at the international level by the 1995 Food and Agriculture Organization (FAO)/World Health Organization (WHO) Codex Alimentarius Commission definition of dietary fiber: “dietary fiber is the edible plant or animal material not hydrolyzed by the endogenous enzymes of the human digestive tract as determined by the agreed upon method.”11 AOAC official methods of analysis for dietary fiber have been adopted by many countries, including the United States, as the basis for food and food product labeling.10 Unfortunately, definitions based on analytical methods do not include reference to the physiological effects of dietary fiber hypothesized years earlier. Therefore, the American Association of Cereal Chemists (AACC) appointed an expert committee to evaluate the definitions of dietary fiber and solicit worldwide input. The 2000 AACC definition is: Functional fiber consists of isolated, non-digestible carbohydrates that have beneficial physiological effects in humans. ● Total fiber is the sum of dietary fiber and functional fiber.1 A proposal for a definition and methods of analysis of dietary fiber content is also the subject of discussion by the Codex Committee on Nutrition and Foods for Special Dietary Uses.14 The definition under consideration states: ● Dietary fibre consists either of Edible, naturally occurring in the food as consumed, non digestible material composed of carbohydrate polymers* with a degree of polymerisation (DP) not lower than 3, or of Synthetic carbohydrate polymers (DP ⱖ 3). Dietary fibre is neither digested nor absorbed in the small intestine and has at least one of the following properties: Increase stools bulk Stimulate colonic fermentation** Reduce blood total and/or LDL cholesterol levels Reduce post-prandial blood glucose and /or insulin levels. * When derived from a plant origin dietary fibre may include fractions of lignin and/or other compounds when associated with polysaccharides in the plant cell walls and if these compounds are quantified by the AOAC gravimetric analytical method for dietary fiber analysis: Fractions of lignin and the other compounds (Proteic fractions, phenolic compounds, waxes, saponins, phytates, cutin, phytosterols, etc.,) intimately “associated” with plant polysaccharides are often extracted with the polysaccharides in the AOAC 991.43 method. These substances are included in the definition of fibre insofar as they are actually associated with the poly-oligo-saccharidic fraction of fibre. However, when extracted or even re-introduced into a food containing non digestible polysaccharides, they cannot be defined as dietary fibre. When combined with polysaccharides, these associated substances may provide additional beneficial effects. ** The statement “Stimulation of colonic fermentation” is added to take into account the Nutrition Reviews姞, Vol. 64, No. 1 TESTS AND CRITERIA FOR DISTINGUISHING DIETARY AND FUNCTIONAL FIBERS The IOM dietary fiber definition as finally developed1 includes plant cell wall and storage carbohydrates common in foods, and includes natural and manufactured or isolated and low-molecular-weight carbohydrates as functional fiber. This definition allows for the inclusion of isolated fibers for incorporation into foods and a declaration as fiber once physiological effects in humans are established. As with other macronutrients, investigations into the health effects of fiber consumption drive research in two directions: analytical methods to detect and measure fiber and clinical studies to establish physiological and health effects of fiber. The tests, criteria, and issues surrounding these two areas were discussed at the workshop. Analytical Methods Numerous methods exist to measure various components and combinations of fiber substances. Presently, various AOAC-approved methods are based on the fact that, physiologically, dietary fibers remain undigested by human enzymes.7 These methods use combinations of enzyme preparations, separations, and purifications to isolate non-digestible fiber fractions, which are then assayed by a number of validated procedures. However, no method exists to distinguish between intrinsic fiber and that which is intentionally introduced into a food product. Also, the various methods do not necessarily identify the same combinations of compounds as dietary fiber. For example, AOAC Method 985.29 captures some inulin in its determination of dietary fiber, while AOAC Method 994.13 does not measure inulin. Several of these methods were discussed at the workshop to explore their strengths and weaknesses under the IOM definition. 33 Downloaded from http://nutritionreviews.oxfordjournals.org/ by guest on September 18, 2016 Carbohydrate polymers (DP ⱖ 3), which have been obtained from food raw material by physical, enzymatic or chemical means, or of effects resulting from the fermentation of fibre (production of metabolites, modification of the flora, effects associated with acidification of the lumen contents, with modification of certain enzymatic activities (e.g. effect on glycuro-conjugated estrogens) or the production of a large quantity of short chain fatty acids and in particular butyrate which is thought to contribute to the proper functioning of the colonic mucosa and which might be beneficial in the prevention of several types of colon disease, including colon cancer. The physiological effects of fibre cannot be restricted to the colon. Epidemiological and interventional studies have demonstrated that protective properties of fibre are—above all— observed on cardiovascular diseases. 34 According to the IOM recommendations,1,13 functional fiber should be measured prior to addition to the food. This would avoid the problems of double counting certain fibers if they or a derivative already occur in the food; examples are pectins, inulin, fructooligosaccharides, and beta-glucans.1,13 However, workshop participants indicated that, for compliance purposes, testing of foods after the addition of functional fiber is necessary. With current methods, it is not possible to assess dietary fiber and functional fiber in the final sample if the fiber added is already present in its intrinsic and intact form in the food. Since the IOM was not charged with determining new analytical methods, a collaborative effort will have to occur among industry, academic, and governmental laboratories to modify or combine current methods and, where necessary and feasible, develop new ones to accurately measure dietary and functional fiber in finished food products. Physiological Effects Dietary fiber is clearly recognized to play an important role in a healthy diet. The benefits of dietary fiber are not disputed, and by definition all dietary fibers are presumed to have a physiological effect. However, the specific nature of the beneficial physiological effect is not designated in the IOM definition.1,13 According to the IOM, specific physiological effects were not identified as part of the definition because new beneficial effects are likely to be discovered. In contrast, based on the IOM definition, physiological effects must be shown for functional fiber. Specific measurable physiological effects of fiber that could be used to establish functionality must be designated. Participants at the workshop noted that, given the lack of acceptable physiological criteria for characterizing dietary fibers, establishing such criteria for classification of functional fibers might be difficult. To measure fiber, particularly functional fiber, by the IOM definitions will require new approaches. First, some criteria for functionality need to be established. For example, if fermentability and viscosity are to be accepted criteria for functionality, as suggested in the IOM reports,1,13 then in vitro tests need to be developed that closely mimic the in vivo situation. Methods already exist for batch fermentability and chemical viscosity that could be modified and defined with clear protocols to establish functionality. In choosing clinical tests of functionality, such as reduction of serum lipids, improved laxation, and modulation of blood glucose, reference standards should be developed and a meaningful degree of change relative to the effects of a standard material needs to be decided, similar to the Canadian regulation surrounding laxation as an accepted physiological effect Nutrition Reviews姞, Vol. 64, No. 1 Downloaded from http://nutritionreviews.oxfordjournals.org/ by guest on September 18, 2016 There are two general classes of methods that capture multiple substances as part of a total fiber determination: enzymatic-gravimetric methods (AOAC Methods 985.29 and 991.43) and enzymatic-chemical methods (AOAC Method 994.13).9 The initial procedures to remove fat and/or sugar from the sample are similar, including enzymatic digestion to remove starch and protein, dilute alcohol precipitation of soluble components, and isolate residues by centrifugation. However, in enzymatic-chemical methods, the resulting residue is further treated and fractions assayed for identification of neutral sugars as monosaccharides, uronic acids, and Klason lignin by mass spectrophotometry, gas chromatography, colorimetry, or high-performance liquid chromatography. Enzymatic-chemical methods are tedious and more costly than enzymatic-gravimetric methods, and also require special skills. Additionally, the extra effort to perform the enzymatic-chemical procedures does not guarantee the elimination of tannins and Maillard reaction products from the total fiber determination (although it does reduce the content of these compounds compared with enzymatic-gravimetric methods). Workshop participants agreed that more research is needed to modify current methods and to develop new methods to adequately account for all substances that qualify as dietary fiber and functional fiber under the IOM definition. As with all methods, newly developed procedures should have safeguards to avoid double counting when methods are combined and careful steps in sample preparation to capture all needed constituents and eliminate all substances that could be confounders. Questions were raised as to whether the IOM definition of dietary fiber includes the specific oligosaccharides fructan and polydextrose, which are quantitated using separate, specific procedures (AOAC Methods 985.29 and 991.43, respectively).13 According to the IOM reports,1,13 low-molecular-weight fructans (such as those found in Jerusalem artichoke and onions) would be included as dietary fiber as long as they are intrinsic and intact. Likewise, according to the IOM,1,13 isolates of low-molecular-weight fructans would be included as functional fiber because they have been shown to have physiological health benefits. Analytical values for dietary, functional, and total fiber must include all polysaccharides, resistant starch, oligosaccharides, and lignin. This makes analysis more complicated, but approved methods exist to measure each of these specific non-digestible carbohydrate materials individually, so full analysis is possible. For example, to measure polydextrose in the analysis of total dietary fiber, one could analyze the sample with AOAC Method 985.29, collect the filtrate from precipitated fiber, analyze for polydextrose by AOAC Method 2000.11, and add the two quantities.9 Regulatory Issues The IOM definition of fiber has created a number of concerns about the impact on regulations. The impact of the division of fiber into dietary and functional fiber is a major issue. There are also concerns about what criteria need to be met to qualify as a functional fiber. If a Nutrition Reviews姞, Vol. 64, No. 1 material meets the criteria to be a functional fiber, will it automatically qualify for a structure-function claim? As discussed above, it may be necessary to put regulations in place that prescribe specific methods for quantifying functional and dietary fiber and for assessing functionality in terms of beneficial physiological effects in humans. The Canadian system for distinguishing novel-functional fiber from intact dietary fiber was discussed in depth at the workshop, because it may be used as a model for implementing the IOM definition. Studying the Canadian program may also help in determining the potential impacts of the IOM definition, if adopted by the FDA, on regulations in the United States. However, it should be pointed out that when a “novel fiber” in Canada meets functional criteria, it becomes listed as dietary fiber with no differentiation from other dietary fibers. Within the Canadian system, non-native fibers are from traditional foods but do not occur naturally in the foods to which they have been added (e.g., oat bran added to a wheat starch pudding). Novel fibers are those that have not traditionally been part of the human diet (e.g., xanthan gum). The Canadian definitions of fiber are as follows: A “novel fiber” or “novel fiber source” means a food that is manufactured to be a source of dietary fiber and a) that has not traditionally been used for human consumption to any significant extent or b) that has been chemically processed, e.g. oxidized, or physically processed, e.g. very finely ground, so as to modify the properties of the fiber contained therein, or c) that has been highly concentrated from its plant source).17 In Canada, to include a “novel fiber” as a “dietary fiber,” it must meet the definition of a novel fiber (see above), measure as dietary fiber by an accepted method, and have proven physiological function.15,16 The regulations specify methods that can be used to measure dietary fiber and describe criteria for studies assessing physiological effects (functionality). To be considered a valid study, effects should be assessed in a clinical trial that reports the type and number of subjects; the experimental and control diets should be defined; and the outcomes of the study should be compared with a reference material and a positive control. With respect to laxation as an accepted physiological effect of dietary fiber, the test fiber must show 50% of the effect of the standard positive control, wheat bran. Thus, the regulations in Canada prescribe (for some physiological effects) the criteria, tests, and standards to assess fiber analytically and functionally. However, the Canadian system may be considered to have overly stringent requirements for a 35 Downloaded from http://nutritionreviews.oxfordjournals.org/ by guest on September 18, 2016 of dietary fiber.16 Additionally, it is possible that new biomarkers of fiber functionality will be included as their importance in health promotion is accepted. Further, less-invasive procedures or novel animal or in vitro models for assessing bowel function could be developed and added to the list of protocols to evaluate the functionality of fiber. Also at issue is whether functional and dietary fiber have significantly different beneficial physiological effects that require the establishment of a distinction between them. “Beneficial physiological effects” are a requirement for functional fiber in the IOM definition but not for dietary fiber. Even a material isolated from a native plant source classified as dietary fiber must be shown to have a physiological effect. In discussing this point, the IOM fiber panel report13 states that studies designed to investigate the physiological effects of dietary fiber (or dietary fiber compared with functional fiber) are often complicated by the inability to separate the effects of the dietary fiber from the associated nutrients. However, it was noted that many of the beneficial physiological effects of fiber, both in human and animal studies, were determined using isolated (and, by IOM definition, functional) fibers. In Canada, specific physiological benefits have been included in the criteria to qualify non-native or novel fibers for addition to foods.15,16,17 Criteria have been established for three recognized physiological effects: regularizing colonic function, normalizing serum lipids, and attenuating the postprandial rise in blood glucose. A fourth, weight control/suppressing appetite, was reviewed for inclusion in Canada’s regulation, but studies have not yielded reliable, reproducible results. Therefore, weight control is not yet considered an acceptable criterion to establish functionality. However, it is foreseeable that in the future, weight control or other health benefits attributed to the consumption of dietary or functional fiber could make the list of criteria to establish functionality. The IOM reports1,13 state that acceptable physiological effects must be identified and criteria established if the definition is implemented. Standard protocols would be needed to determine functionality. Questions were raised in the workshop as to how this process would be accomplished and what level of significance would be required. Consumer Issues The possible impact on consumer attitudes and behaviors that could result from changing the IOM fiber definition and fiber-related labeling regulations was also addressed. Consumers are confused about fiber. According to several studies discussed at the workshop, less than 50% of individuals in the United States with diabetes correctly identified foods with fiber; in a study in the United Kingdom, approximately 50% of subjects listed meat as a source of fiber.18 However, 60% of 1000 adults surveyed said they are trying to choose a diet with adequate fiber and look for it on the label at least some of the time.19 In a recent consumer survey, 85% of consumers polled indicated that they were concerned 36 about the nutritional content of the foods they eat, yet in an unaided question, none mentioned fiber as an item of concern. Whole grains and fiber were mentioned by 10% of consumers as something eaten to ensure a healthy diet. When prompted, only 0.5% of consumers indicated that they were concerned about fiber. Additionally, fiber ranks 9th on consumers’ lists for label items considered when purchasing foods. For the typical consumer, fiber is not high on the list of concerns compared with calories, fats, and sodium when making food choices. Therefore, there is a gap in consumer behavior and consumer knowledge with respect to dietary fiber. If the IOM recommendations are implemented, the nutrition facts panel could include a line for total, dietary, and functional fiber. It is possible this could increase consumer awareness and interest in fiber and possibly increase the consumption of fiber. This would be a desirable outcome, because currently Americans consume, on average, 15 g/d fiber and this amount appears to be decreasing instead of increasing to meet the IOM recommendations of 14 g/1000 kcals (approximately 28 g/d)1. Unfortunately, the label change would be more likely to confuse consumers. Consumers think current food labels are already too complicated and want simpler ones.20,21 If dietary fiber and functional fiber are separate label entities, functional fiber could potentially be perceived as superior to dietary fiber. This could have two possible impacts. It could increase functional and/or total fiber intakes in the diet because consumers might specifically select products labeled as containing functional fiber. The demand by consumers for foods with functional fiber could promote the development of new fiberenhanced products. Alternatively, increased demand for products with added functional fiber and few other nutritional advantages could decrease the quality of the diet, especially if consumers reduce their selection of sources of dietary fiber in the form of fruits, vegetables, and whole grains. This could lead to a net decrease in total fiber intake or a reduction in the overall quality of the diet. Many participants in the workshop favored the use of the functional-dietary fiber distinction as an internal regulatory nomenclature, but with the information not placed on the label. This would harmonize with current Canadian regulations. Practically, the ultimate physiological impact of dietary and functional fiber should be identical, and in most cases one would be unable to analytically distinguish the effects of one from another in a final food product. The message sent to consumers and manufacturers by changing the nutrition content label should be further investigated by focus groups and other studies. Nutrition Reviews姞, Vol. 64, No. 1 Downloaded from http://nutritionreviews.oxfordjournals.org/ by guest on September 18, 2016 material to be classified as a novel fiber, since only four substances (ground, bleached oat hulls, soy cotyledon, sugar beet fiber, and psyllium seed husk) have been granted novel fiber status since 1985. Canadian regulations also require that, in addition to providing beneficial physiological effects, the safety of novel fiber sources must also be established before they may be used as ingredients in foods. If safe, they may be used in foods, but cannot be claimed as a source of dietary fiber unless they have been shown to have physiological efficacy. If efficacy has not been shown, they are classified as an unproven novel fiber. Approved novel fibers are included in the total fiber declaration on the Canadian nutrition facts panel; the Canadian food label does not distinguish between intact and added fibers. There are three reasons that the Canadian model of declaring only total fiber on the label may be useful in the United States. First, the beneficial physiological effects of a novel fiber that has been accepted as a functional fiber compared with dietary fiber are the same. Second, it keeps the number of terms on the label from increasing, which could confuse consumers. Third, there would no longer be a need for new methods to distinguish dietary from functional fiber for label compliance purposes. Confusion could also result in the area of fiber health claims. If a material meets the criteria to be called functional fiber, will it automatically qualify for a health claim? Is there a system in place within the FDA for processing and sorting through new claim submissions? The IOM did not make recommendations for a new fiber claim process using the new definition. Further adding to potential confusion are the existing health claims that refer to soluble and insoluble fiber. The IOM report suggests that these terms should no longer be used. Thus, the health claims regulations with regard to these terms will need to be updated. ACKNOWLEDGEMENTS The IOM definitions of dietary fiber and functional fiber impact analytical chemistry, clinical research, product development, labeling regulations, and ultimately consumer health. However, there are areas where gaps in knowledge and understanding still exist. These are summarized as a series of questions listed below. ● Who should decide which analytical or functionality tests are acceptable? ● Who should identify acceptable physiological effects and criteria? ● Should analytical methods for quantitation and functionality be included in a regulation? ● Should the AOAC/Codex model for acquiring new methods be used when setting methods for testing physiological criteria? ● Are there true functional differences between dietary fiber and functional fiber in isolation? ● Are dietary fiber and functional fiber physiologically different when they are in foods? Are there enough data to support a distinction between the two? ● Can there be differentiation by analysis of dietary fiber and functional fiber? ● Are there substances that are considered to be dietary fiber by current AOAC methods but that do not have any physiological function? ● What criteria need to be met currently to qualify as a functional fiber? ● What level of science will be required for “new” physiological effects? ● What physiological functions should be considered, and at what level, for a food ingredient to qualify as a functional fiber? ● If a material meets the criteria to be a functional fiber, will it automatically qualify for a structurefunction claim? ● Does the infrastructure exist to rigorously evaluate the science supporting a functional fiber claim? ● How can the current fiber categories of soluble and insoluble be integrated into the proposed definitions? ● How will implementation of the IOM definition impact innovation? ● What will constitute approval of functional fibers? This work was supported by a grant from the Technical Committee on Carbohydrates of the North American Branch of the International Life Sciences Institute (ILSI NA). (For more information about the Committee or ILSI NA, call 202-659-0074 or E-mail ilsina @ilsi.org.) The opinions expressed herein are those of the authors and do not necessarily represent the views of ILSI NA. The authors would like to thank the members of the Technical Committee on Carbohydrates and its Fiber Working Group for their support of this workshop and publication. We also thank the speakers for their review of the manuscript to ensure the accuracy of the information presented. The Committee appreciates the stimulating presentations by the speakers, the interactive participation of the guests, and the assistance of Richard Carson, Senior Project Manager, and the staff of ILSI NA, ILSI Europe, and ILSI, who contributed to the successful workshop. CONCLUSIONS Changing the definition of dietary fiber in the United States and possibly Canada has far-reaching analytical, regulatory, industry, and consumer impacts, and the full effects and understanding of these changes need to be carefully addressed. Consideration must be given to existing dietary fiber definitions to harmonize with other countries, particularly trading partners, and to ensure that the resulting regulations can be implemented and enforced. Nutrition Reviews姞, Vol. 64, No. 1 Workshop Speakers and Panelists Ms. Sue Borra, International Food Information Council Dr. Steve Brooks, Nutrition Research Division, Health Canada Dr. Ian Brown, the National Starch and Chemical Company Dr. Brenda Derby, Center for Food Safety & Applied Nutrition (CFSAN), FDA Dr. Jon DeVries, General Mills Dr. Kathy Ellwood, CFSAN, FDA Dr. Julie Jones, College of St. Catherine Dr. Betty W. Li, US Department of Agriculture (USDA) (Ret.) Dr. David Lineback, Joint Institute for Food Safety & Applied Nutrition, (JIFSAN), University of Maryland Dr. Joanne Lupton, Texas A&M University Dr. Jeanne Rader, CFSAN, FDA Dr. Joanne Slavin, University of Minnesota Dr. Alison Stephen, Heart & Stroke Foundation of Canada Dr. Paula Trumbo, CFSAN, FDA Dr. Allison Yates, formerly IOM, National Academies of Sciences, currently with ENVIRON ILSI North America Statement of Purpose: The North American branch of the International Life Sciences Institute (ILSI NA) is a public, non-profit scientific foundation. ILSI NA advances the understanding and application of scientific issues related to the nutritional quality and safety of the food supply as well as health issues related to consumer self-care products. The organization carries out its mission by sponsoring relevant research programs, professional education programs and workshops, seminars, and publications, as well as providing a neutral forum for government, academic, and 37 Downloaded from http://nutritionreviews.oxfordjournals.org/ by guest on September 18, 2016 KNOWLEDGE GAPS IDENTIFIED industry scientists to discuss and resolve scientific issues of common concern for the well-being of the general public. ILSI NA also strives to foster the career development of outstanding new scientists. ILSI NA’s programs are supported primarily by its industry membership. 12. 13. REFERENCES 1. 2. 4. 5. 6. 7. 8. 9. 10. 11. 38 14. 15. 16. 17. 18. 19. 20. 21. Nutrition Reviews姞, Vol. 64, No. 1 Downloaded from http://nutritionreviews.oxfordjournals.org/ by guest on September 18, 2016 3. Food and Nutrition Board, Institute of Medicine. 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