When FDA modernized the nutrition labeling rules in 2016, it also changed how dietary fiber is calculated. The new rule on dietary fiber raised the bar by requiring that ingredients used for fiber fortification in processed foods have at least one FDA-recognized human health benefit.

dietary fiber definition

This definition has the practical effect of prohibiting manufacturers from counting, declaring, and making claims based on the fiber from a wide range of novel isolated or synthetic non-digestible carbohydrate ingredients — unless and until FDA determines that consumption of the ingredient has physiological effects that are beneficial to human health. Back in 2016, FDA identified a short list of seven isolated or synthetic non-digestible carbohydrates that are appropriate for inclusion in the dietary fiber calculation:

  • [Beta]-glucan soluble fiber;
  • Psyllium husk;
  • Cellulose;
  • Guar gum;
  • Pectin;
  • Locust bean gum; and
  • Hydroxypropylmethylcellulose.

In response, manufacturers submitted numerous citizen petitions requesting that FDA evaluate the health benefits of other non-digestible carbohydrate ingredients. On June 15, 2018, the FDA issued Final Guidance for Industry on The Declaration of Certain Isolated or Synthetic Non-Digestible Carbohydrates as Dietary Fiber on Nutrition and Supplement Facts Labels. This guidance document signals FDA’s intention to add eight more dietary fiber sources to the list:

  • Arabinoxylan;
  • Alginate​;
  • Inulin and inulin-type fructans
    (including chicory root fiber or chicory root extract);
  • High amylose starch (resistant starch 2);
  • Galactooligosaccharide;
  • Polydextrose;
  • Resistant maltodextrin/dextrin; and
  • Mixed plant cell wall fibers
    (obtained from fruits, vegetables, grains, legumes, pulses, nuts, and other plants that undergo processing).

“Mixed plant cell wall fibers” encompasses a wide range of ingredients that contain two or more of the following plant cell wall fibers in varying proportions: cellulose, pectin, lignin, beta-glucan, and arabinoxylan.  

In expanding the list, FDA recognized physiological benefits beyond just improvement of digestion and suppression, which are typically associated with consumption of dietary fiber. For example, FDA determined that inulin and inulin-type fructans have a positive effect on bone mineral density and increase absorption of calcium. Despite this expansive view of physiological benefit, FDA denied citizen petitions seeking recognition of isomaltoogliosaccharides (IMOs), gum acacia, and xanthan gum as sources of dietary fiber, concluding that the evidence submitted does not show that consumption of these ingredients have any physiological effect that is beneficial to human health.

FDA is continuing to review the scientific basis for claimed health benefits of several types of fiber — including, carboxymethylcellulose, retrograded cornstarch, retrograded wheat and maize starch, modified wheat starch, konjac flour —  which remain in regulatory limbo. FDA Commissioner Scott Gottlieb has said, “[FDA’s] work is not done. We have received additional petitions asking for additional fibers to be recognized in a similar fashion to the eight dietary fibers we are identifying today… [W]e will continue to evaluate additional dietary fibers on a rolling basis, and we expect that additional fibers may be recognized in the future.”

The new dietary fiber rules come into effect alongside the other Nutrition Facts & Serving Size rules or upon use of the new Nutrition Facts format. (For information about those compliance deadlines, see our prior post.)  

Implications for Food Producers
While the recently issued FDA Guidance is non-binding, the Agency has indicated that it will pursue formal rulemaking to add the eight additional fibers to the official list. In the meanwhile, it will exercise enforcement discretion. This means that, effective immediately the FDA is allowing manufacturers to count the fiber from any of the above-listed isolated or synthetic non-digestible carbohydrates for purposes of quantitative and percent Daily Value declarations in the Nutrition Facts Panel and Nutrient Content Claims on labeling and in the marketing of food products.  

Food producers should make sure that their dietary fiber calculations are based only upon the fiber contributed by approved sources.  Fiber content should be recalculated for products that contain any of the newly approved or recently rejected fiber sources.  

Additionally, when a product contains both a) allowable dietary fiber and b) added non-digestible carbohydrates that do not meet the definition of dietary fiber, manufacturers must create and keep records that verify the amount of dietary fiber declared on the label.

If you have questions about the implications of this guidance on your food labeling, Nicole or Lauren are happy to offer advice.