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This article outlines the new regulatory definition of dietary fiber under the US Food and Drug Administration’s final rule for Nutrition and Supplement Facts labeling, including requirements for declaring ingredients as dietary fiber on the label outlined in the regulation. The author offers a timeline on FDA’s activities in the area of dietary fiber and discusses implications for the food and dietary supplement industry.
In May 2016, the US Food and Drug Administration (FDA) introduced sweeping changes to food and dietary supplement labeling requirements with the issuance of the final rule, Revision of the Nutrition and Supplement Facts Labels.1 The final rule represents the first major revision to the Nutrition Facts label since 1993 and impacts all food labels. Additionally, many dietary supplements will have to undergo either reformulation or label changes. One of the major changes affecting both conventional food and dietary supplements is the new definition for “dietary fiber.”
In the final rule, dietary fiber is defined as “non-digestible soluble and insoluble carbohydrates (with three or more monomeric units), and lignin that are intrinsic and intact in plants; isolated or synthetic non-digestible carbohydrates (with three or more monomeric units) determined by FDA to have physiological effects that are beneficial to human health.” Previously, FDA did not have a regulatory definition of dietary fiber, but instead, relied on analytical methods for the measurement of dietary fiber in food.
Non-Digestible Carbohydrates (NDCs), intrinsic to and intact in plant-based foods, are considered by FDA to meet the definition of dietary fiber and may be declared as a dietary fiber on the Nutrition and Supplement Facts label. Isolated or synthetic NDCs will only meet the definition if (a) FDA grants their inclusion in the definition in response to a petition demonstrating that such carbohydrates have a physiological effect(s) that is beneficial to human health or (b) they are the subject of an authorized health claim.
In the final rule, FDA included the following seven isolated or synthetic NDCs in the definition of dietary fiber:
Of these ingredients, beta glucan and psyllium husk are the subject of authorized health claims. For the remaining five ingredients, FDA determined that scientific evidence supports a beneficial physiological effect to human health.
In addition to defining dietary fiber, FDA increased the Dietary Reference Value (DRV) for dietary fiber from 25g to 28g. The DRV is used to calculate the Percent Daily Value (%DV) for nutrients on food and Supplement Facts labels. Therefore, to achieve the same %DV for dietary fiber as under the previous regulation, a product would have to contain more dietary fiber. Another relevant change is that NDCs (regardless of whether they meet the definition of dietary fiber) have been assigned a caloric value of 2 kcal/g, a decrease from 4 kcal/g. This change means that under the new labeling requirements foods containing NDCs will have a lower total caloric value listed on the label.
In November 2016, FDA published the Science Review of Isolated and Synthetic Non-Digestible Carbohydrates, a summary of the scientific data the agency had reviewed on 26 isolated or synthetic NDCs, but without reaching a conclusion.2 At the same time, FDA issued a draft guidance document, Scientific Evaluation of the Evidence on the Beneficial Physiological Effects of Isolated or Synthetic Non-Digestible Carbohydrates Submitted as a Citizen Petition (21 CFR 10.30): Guidance for Industry (Draft Guidance).3The Draft Guidance provided information on “intact and intrinsic” dietary fibers, detailed FDA’s thinking at the time on the information needed in a dietary fiber petition and revealed the agency’s scientific evaluation process for petitions. FDA requested scientific data, information and comments regarding the 26 isolated or synthetic NDCs, as well as comments in response to the Draft Guidance. The comment period for both documents closed in February 2017.
In addition to the 26 isolated or synthetic NDCs under review, FDA received 12 citizen petitions in 2016 and 2017 for ingredients seeking to be included in the definition of dietary fiber for nutrition labeling purposes. Petitions were received for isomaltooligosaccharides (two petitions), fructans/inulin/oligofructose (two petitions), soy fiber, polydextrose, rice bran products, xylooligosaccharide, sugar cane flour, resistant starch 4 (phosphorylated) and resistant maltodextrin/soluble corn fiber (two petitions).
In March 2018, more than a year after the comment period closed for the Draft Guidance, FDA released its final Guidance for Industry: Scientific Evaluation of the Evidence on the Beneficial Physiological Effects of Isolated or Synthetic Non-Digestible Carbohydrates Submitted as a Citizen Petition (21 CFR 10.30) (Final Guidance).4 In the Final Guidance, FDA provided additional details and explanations of the information the agency will consider in its evaluation of fiber petitions. However, the agency maintained its general position from the Draft Guidance—it will consider data primarily from human intervention studies to assess whether an ingredient provides a beneficial physiological effect. FDA listed examples of endpoints it considers to be beneficial physiological effects, including lowering blood glucose and cholesterol levels, lowering blood pressure, improving laxation and bowel function, increasing mineral absorption and reducing energy intake. This list, FDA noted, was not exhaustive.
One change in the Final Guidance is that FDA indicated it will consider clinical trials using subjects with a disease linked to the studied effect, but only when it is appropriate to extrapolate the study results to individuals who do not have the disease. For example, FDA would consider studies on constipated individuals when evaluating whether a fiber improves laxation. However, the agency would not consider data on individuals with diarrhea compared to the healthy population when evaluating improved laxation because there are many different causes for diarrhea, most of which are not related to how an NDC could improve laxation.
In the Final Guidance, FDA also removed statements regarding “intrinsic and intact” fibers that were in the Draft Guidance. The agency indicated plans to issue a separate guidance addressing “intrinsic and intact” fibers to clarify what constitutes an “intrinsic and intact” or naturally occurring fiber (which does not require approval by FDA to be included in the declaration of dietary fibers on the label) versus an isolated or synthetic NDC.
On 14 June, 2018 FDA issued Guidance for Industry: The Declaration of Certain Isolated or Synthetic Non-Digestible Carbohydrates as Dietary Fiber on Nutrition and Supplement Facts Labels (New Guidance). The guidance identified eight additional NDCs the agency intends to add to the regulatory definition of dietary fiber, including mixed plant cell wall fibers, arabinoxylan, alginate, inulin and inulin-type fructans, high amylose starch (resistant starch 2), galactooligosaccharide, polydextrose and resistant maltodextrin.5 The New Guidance indicated to manufacturers that FDA intends to exercise enforcement discretion relative to the declaration of the aforementioned NDCs as dietary fiber on nutrition labels pending completion of a rulemaking to amend the definition of dietary fiber. In the New Guidance, FDA defined plant cell wall fibers as ingredients containing two or more of the following plant cell wall fibers in varying proportions: cellulose, pectin, lignin, beta-glucan and arabinoxylan. In the accompanying science review, FDA provided a non-exhaustive list of mixed plant cell wall fibers, including apple fibers, bamboo fibers, barley fibers, carrot fibers, citrus fibers, cocoa fibers, corn fibers (e.g., corn hull fiber), cotton seed fibers, oat fibers (e.g., oat hull fiber), pea fibers (e.g., pea hull fiber, pea seed coat fiber, inner cotyledon pea fiber), rice bran fibers, soy fibers (e.g., soy hull fiber, soy polysaccharide, soy cotyledon fiber), sugar beet fibers, sugar cane fibers and wheat fibers.6 In addition, FDA stated its intent to amend the caloric value of polydextrose on Nutrition and Supplement Facts labels to 1 kcal/g through rulemaking and to exercise enforcement discretion with respect to using this caloric value in the interim.
In addition to the inclusion of mixed plant cell wall fibers to the definition of dietary fiber, FDA addressed the issue of intrinsic and intact NDCs in an appendix to the New Guidance. In the 2016 Draft Guidance, the agency previously stated it did not consider NDCs obtained from non-food sources, such as stems, branches, and trunks of trees, edible hulls and husks, seaweed, and fungus, to be intrinsic and intact.7 In the appendix to the guidance, FDA recognized certain seaweeds and fungi are considered foods and stated that intrinsic and intact NDCs found in seaweed and fungi, consumed as food, meet the dietary fiber definition.
In a statement issued on 14 June 2018, FDA Commissioner Scott Gottlieb, MD, indicated the agency has received and is evaluating additional petitions for dietary fiber.8 He also stated that FDA welcomes “the submission of additional petitions in the future as science emerges and as new ingredients are identified” and that the agency’s expectation is that it will “continue to evaluate additional dietary fibers on a rolling basis, and [it] expect[s] that additional fibers may be recognized in the future.”
Companies have less than 18 months to comply with the new labeling requirements, as the compliance dates were recently extended from 26 July 2018 to 1 January 2020 for manufacturers with $10 million or more in annual food sales, with an additional year to comply for manufacturers with less than $10 million in annual food sales.9 Companies having products containing one of the eight isolated or synthetic NDCs FDA plans to add to the regulatory definition of dietary fiber, as well as companies supplying these ingredients, can finally breathe a sigh of relief. For products containing NDCs that have not been recognized by FDA as dietary fiber, decisions will have to be made on whether to maintain the product formulation, but not be able to include the ingredient in the declaration of dietary fibers on the label or reformulate the product to replace the ingredient with one that has been accepted by FDA as a dietary fiber. Reformulation is costly and time consuming, as individual NDCs have different sensory properties, physical characteristics, and technical effects. Therefore, one NDC cannot be simply replaced with another in a particular product formulation.
Companies that have dietary fiber petitions currently under review by FDA or are planning to submit a petition should be aware that if FDA has not yet responded to the petition by the time the compliance date for nutrition labeling has passed, the company cannot include the NDCs that are the subject of the petitions in the declaration of dietary fiber.10
More than two years have passed since the issuance of the final rule overhauling the Nutrition and Supplement Facts label. Gaining clarity on FDA’s definition of dietary fiber has been a slow process and much work remains for companies to meet the deadline for complying with the new labeling requirements.
Andrea W. Wong, PhD, is vice president, scientific and regulatory affairs, Council for Responsible Nutrition (CRN). She plays an integral role in CRN’s science and regulatory affairs department, responding to emerging scientific and regulatory issues as well as advocating for science-based nutrition. Wong also provides scientific expertise in evaluating research relevant to the benefits and safety of ingredients and dietary supplements, and in support of CRN’s nutrition policy activities. She leads proactive, self-regulatory initiatives, including the development of best practices guidelines for industry on product labeling and formulation. She may be contacted at email@example.com.
Cite as: Wong A W. “Digesting FDA’s New Regulatory Definition of Dietary Fiber and its Impact on the US Food and Dietary Supplement Industry.” Regulatory Focus. July 2018. Regulatory Affairs Professionals Society