Bethesda, Maryland, USA
March 26, 2014 – March 28, 2014

A Framework for Determining the Physiological Benefits of Fiber

Session #11
28 March 2014

The Agenda for the 10th Vahouny Fiber Symposium is available here.


Jon DeVries

Paper 1: The Nine Vahouny health benefits: the launch of a new database
Nicola McKeown

Abstract: Evidence mapping is a new methodology in nutritional epidemiology, designed to capture the research activity in topic areas and has shown to be a useful tool in influencing research priorities, systematic reviews, and meta-analyses. The health benefits of dietary fiber have been extensively studied; yet, there is no publically available dataset that comprehensively includes a searchable list of dietary fibers and links them to specific health benefits. The CODEX Alimentarius definition of dietary fiber includes all nondigestible carbohydrate polymers with a degree of polymerization of 3 or more and can be classified into three categories (1) fibers that are intrinsic and intact; (2) fibers that are extracted from food materials by some physical, chemical, or mechanical means; and (3) fibers that are synthesized or modified. A comprehensive dietary fiber database, designating individual fibers to a Codex fiber type, would serve as a useful tool to help scientists in academia and industry identify potential research gaps for specific fibers in relation to health outcomes. To build this evidence-map database, we conducted a literature search for intervention studies and prospective studies of humans published in English, from 1946 to September 2013. Our search strategy included a broad definition of fiber search terms, as well as search terms for the nine agreed upon Vahouny health outcomes. Screening of identified abstracts was based on a priori defined eligibility criteria and used a low threshold for inclusion to minimize the likelihood of rejecting articles of interest. Accepted abstracts (n=7,257) were retrieved and full-text screened. The evidence-map database is built and will be published on the Systematic Review Data Repository (SRDR™), a web-based, publicly available application. This resource will reduce the unnecessary replication of effort in conducting a systematic review by serving as both a central archive and data extraction tool. This presentation will review the methodology, highlight the usefulness in establishing a publically available comprehensive fiber database, and provide examples of how evidence maps can faclilate efficiency of efforts in dietary fiber research.

Paper 2: The case for fiber variety
Julie Jones

Abstract: Dietary fiber (DF) has been listed as a ‘nutrient of concern’ because in the US, and around the world, there is a significant gap between actual and recommended intakes. In some cases, average DF intakes for the population are below half of that recommended; thus, fiber intakes must be increased. In order to do this, a two-pronged effort, that includes a continued effort to increase consumption of foods naturally rich in DF coupled with a call to include foods customarily in the diet that have been fortified with added DF, is necessary. With such an approach, the fiber gap can be narrowed, while making certain that calorie levels remain neutral. Given the current obesity problem, it is critical that fiber must be increased without added calories. This talk will give data about the fiber gap and use diet models to show how the two- pronged approach of increasing fiber-rich foods. This talk will also address another critical aspect to the case for fiber variety. Not only can a variety of fibers help narrow the gap within energy needs, but also insure that a variety of fiber types are consumed. With the right total amount of fiber and the balance of fiber types, the various important physiological roles DF can be fulfilled. Thus an analogy can be made to vitamins, where the optimal diet contains not only right total quantity but also the right balance of various individual DF types.

Paper 3: Approaching fiber from a regulatory perspective
Stuart Craig

Abstract: In early March 2014, the US Food and Drug Administration (FDA) published a proposed rule, outlining tentative determinations and seeking comments regarding revisions to the Nutrition Facts Panel (NFP). In this document, they “tentatively conclude that a regulatory definition for dietary fiber should be one that emphasizes the physiological effect that is beneficial to human health.” They also propose a single definition for dietary fiber that is equivalent to the Institute of Medicine’s definition for ‘total fiber,’ deciding not to distinguish between intrinsic and non-intrinsic sources. Revisions to the NFP are an important step in closing the current fiber gap in the US, and as the FDA moves forward in finalizing this rule, there remain points for discussion on how best to do so. This talk will lay out the approaches by the FDA, Health Canada and CODEX in defining fiber, comparing perspectives on the degree of polymerization, isolated and synthetic non-digestible carbohydrates, analytic methods, caloric value, and physiological benefits. Does the perfect model already exist? If not, is there a combination of approaches that can be employed? By comparing existing and proposed approaches, this talk will pave way for an audience discussion on these issues, with particular focus on how to establish a fiber ingredient as having physiological benefits important to human health.

Panel and Audience Facilitated Discussion
Moderator: Jon DeVries, Panelists: Stuart Craig, Julie Jones

This session was sponsored by the IAFNS Technical Committee on Carbohydrates.

For more information on the 10th Vahouny Fiber Symposium, visit ASN’s website.