Fiber is the part of fruits, vegetables, legumes, grains, and other carbohydrates that is neither digested nor absorbed. It helps keep the intestines working comfortably and helps prevent certain diseases. During the session “A Global Overview of Dietary Fiber Regulations, Facts and Impacts, Part 1” on Monday, June 26, speakers discussed recent changes to the definition of “dietary fiber.”
In May 2016, the U.S. Food and Drug Administration (FDA) issued a final rule amending requirements for Nutrition and Supplement Facts labels, and speaker Paula Trumbo of the FDA said that the final rule includes updating the definition of dietary fiber. Previous regulations on dietary fiber did not define dietary fiber, she said, but relied on analytical methods for measuring total, soluble, and insoluble fiber. Therefore, isolated and synthetic nondigestible carbohydrates could be added to foods and quantified as dietary fiber without providing beneficial physiological effects. With the new definition, Trumbo said, beneficial physiological effects cannot be assumed to exist for isolated or synthesized nondigestible carbohydrates from foods. The final rule for Nutrition Facts labels defines dietary fiber as “non-digestible soluble and insoluble carbohydrates, and lignin that are intrinsic and intact in plants; isolated or synthetic non-digestible carbohydrates determined by the FDA to have physiological effects that are beneficial to human health.”
All naturally occurring fibers are considered intact if no relevant component of them has been removed or destroyed, Trumbo said, and intrinsic if they originate and are included wholly within a food. Intact and intrinsic fiber is assumed to offer physiological benefits. The beneficial physiological effects to human health that have to be demonstrated before an isolated or synthetic carbohydrate can be declared a dietary fiber must include one or more of the following: 1) lowering blood glucose and cholesterol levels, 2) lowering blood pressure, 3) improved laxation and bowel function, 4) increased mineral absorption in the intestinal tract, and 5) reduced energy intake due to a feeling of satiety. Trumbo said that the FDA has determined that only seven isolated and synthetic fibers (i.e., functional) added to foods meet the new requirements: beta glucan soluble fiber, psyllium husk, cellulose, guar gum, locust bean gum, pectin, and hydroxypropylmethylcellulose. Food manufacturers must submit a health claim petition to the FDA to propose identifying other nondigestible carbohydrates as dietary fiber on food package labels. Scientific evidence to support such a claim must be based on human studies and must demonstrate one or more beneficial physiological effects. FDA will also use other factors to determine the strength of the evidence, such as number of participants, health of participants, consistency of results, and so on.
Another speaker, Lina Paulionis of Intertek Scientific and Regulatory Consultancy, said that there was a more than 30-year span between when one regulatory authority specified in 1985 that added dietary fiber should demonstrate physiological benefits and when the FDA adopted that requirement for added or functional dietary fibers in U.S. foods. Because the dietary fiber definition adopted by the United States established a more rigorous definition for functional fibers, it is having an impact on the way international jurisdictions define dietary fibers. As a consequence, Paulionis said, other regulatory authorities now require statistical significance among scientific evidence to support physiological effects of a proposed dietary fiber. There is now harmony between the definition of dietary fiber in Canada, the European Union, and the United States. Paulionis added that despite the increased emphasis on physiological benefits, the only benefit that consumers associate with dietary fiber is laxation/regularity.