Impact of the proposed definition of dietary fiber on nutrient databases

Abstract

Many definitions of dietary fiber exist worldwide, some based on analytical methods and others physiologically based. In March 2001, the Food and Nutrition Board, Institute of Medicine of the National Academy of Sciences released proposed definitions for dietary fiber developed by a panel of experts. The panel held three meetings and a workshop to review existing definitions of dietary fiber, review methods to measure dietary fiber, and receive input from scientists, food companies, consumers, and other interested parties on their viewpoints on a definition for dietary fiber. Based on the Panel's deliberations, the following definitions were proposed: Dietary Fiber consists of nondigestible carbohydrates and lignin that are intrinsic and intact in plants. Functional Fiber consists of isolated, nondigestible carbohydrates that have beneficial physiological effects in humans. Total Fiber is the sum of Dietary Fiber and Functional Fiber. What impact will these definitions have, if adopted? Currently, dietary fiber is defined as compounds that are isolated by analytical dietary fiber methods accepted by the Association of Official Analytical Chemists (AOAC) rather than a formal definition that includes fiber's role in human health. New methods will need to be developed to reflect the accepted definitions for dietary fiber. Additionally, the committee felt that the terms “soluble” and “insoluble” fiber are not meaningful and should no longer be used in labeling. Finally, compounds such as resistant starch and inulin, which do not qualify as dietary fiber under current AOAC methods could be considered Functional Fiber if they show beneficial physiological effects in humans.