Not All Fiber Is Created Equal


Anne Danahy, MS, RDN, LDN

What You’ll See on the New Food Labels

As most registered dietitian nutritionists (RDNs) are aware, the nutrition facts label on packaged food products will soon have a new look, thanks to the final rule for the US Food and Drug Administration’s (FDA) 2016 updates to the Nutrition Facts food labels. Consumers will begin to see these labels within the year, but smaller food manufacturers may have until 2021 to fully comply. The news that portion size, calories, and grams of added sugar will be highlighted on the new labels has received much attention, but other important changes about fiber have also been approved, and this presents an opportunity for dietitians to educate about an important nutrient.

Interest versus consumption

Fiber is an underconsumed nutrient, and this is considered a public health concern because of its impact on overall health. The mean daily intake of fiber in the U.S. is 17 g/day, which is significantly lower than the recommended Adequate Intake (AI) of 14 g/1000 kcal, or about 25 g/day for adult women and 38 g/day for adult males. Currently only 5% of the population meets their AI goals. 2,7

In their annual Food and Health survey, the International Food Information Council found that consumers identify fiber as one of the healthiest components of a food. 1 Food manufacturers often address this interest and demand by adding “isolated,” sometimes known as functional fiber, to foods such as snack bars, cereals or yogurt, to either boost their existing fiber content or to make a low-fiber food appear more nutritious. Previously, fiber could be isolated from any source, added to foods, and counted toward the food’s fiber content on its nutrition facts label. While intact fiber (the fiber that occurs naturally in plant foods) has known health benefits, some of these isolated or synthetic fibers do not provide similar health benefits, yet manufacturers could declare them as fiber on the nutrition facts label.

The FDA’s new ruling

In their 2016 updates to the nutrition facts label, the FDA set a new regulatory definition for dietary fiber, and because of fiber’s wide range of health benefits, it also increased the daily recommended value (DRV) from 25 g to 28 g – a change that could impact a product’s fiber labeling claims.

Under the update, dietary fiber is defined as “non-digestible soluble and insoluble carbohydrates (with 3 or more monomeric units), and lignin that are intrinsic and intact in plants; isolated or synthetic non-digestible carbohydrates (with 3 or more monomeric units) determined by FDA to have physiological effects that are beneficial to human health.”

Naturally occurring fiber that is intrinsic and intact in foods such as whole grains, automatically meets this new definition, but now if a food manufacturer wishes to declare fiber from an isolated or synthetic source, they are tasked with petitioning the FDA to consider scientific proof of its health claim. 5

What passed the fiber definition test

The FDA approved 7 forms of isolated fiber, which meet the definition. These ingredients provide soluble and/or insoluble fiber which scientific studies have confirmed, exhibits physiological benefits such as reducing blood sugar or cholesterol levels, increasing satiety, and improving gastrointestinal function. They include 5:

  • Beta-glucan (soluble fiber)
  • Psyllium husk (soluble fiber)
  • Guar gum (soluble fiber)
  • Pectin (soluble fiber)
  • Locust bean gum (soluble fiber)
  • Hydroxypropylmethylcellulose (soluble fiber)
  • Cellulose (insoluble fiber)

In addition to these 7, they reviewed scientific literature on the following 26 isolated and synthetic non-digestible carbohydrates that have most commonly been added to foods and declared as fiber on the nutrition facts label. Overall, the research they reviewed does not consistently support health benefits, but FDA has asked interested parties to submit further scientific evidence of any benefit of the following non-digestible carbohydrates 6:

  1. Gum Acacia
  2. Alginate
  3. Apple Fiber
  4. Bamboo Fiber
  5. Carboxymethylcellulose
  6. Corn Hull Fiber
  7. Cottonseed Fiber
  8. Galactooligosaccharides
  9. Inulin/Oligofructose/Synthetic Short Chain Fructooligosaccharides
  10. Karaya Gum
  11. Oat Hull Fiber
  12. Pea Fiber
  13. Polydextrose
  14. Potato Fibers
  15. Pullulan
  16. Rice Bran Fiber
  17. High Amylose Corn/Maize Starch (Resistant Starch 2)
  18. Retrograded Corn Starch (Resistant Starch 3)
  19. Resistant Wheat and Maize Starch (Resistant Starch 4)
  20. Soluble Corn Fiber
  21. Soy Fiber
  22. Sugar Beet Fiber
  23. Sugar Cane Fiber
  24. Wheat Fiber
  25. Xanthan Gum
  26. Xylooligosaccharides

The impact for consumers

Food manufacturers unable to demonstrate health benefits of the non-digestible carbohydrates used in their products will be unable to declare them as fiber. However, these ingredients will still add to the total carbohydrate content of the food. These new guidelines will benefit consumers by providing more transparency about the health-promoting ingredients or properties of the foods they choose to eat. Hopefully, they will also force food manufacturers to reformulate products to provide more beneficial fiber, or reduce carbohydrate content in the form of added sugar, to improve the health profile of their products.

The research and debate around the final ruling on fiber is also an opportunity for RDNs to educate consumers about the health benefits of fiber, whether it is intact or isolated. It is a good opportunity to remind the public that adding isolated fibers to highly processed foods does not necessarily make them a healthy choice. Instead, they should, whenever possible, choose whole plant foods that are natural sources of fiber, as they come packaged with other important nutrients. The more consumers learn about what is in their food, and the way it is manufactured, the savvier they can be at the supermarket when it comes to choosing products that promote better health.

Research and recommended reading:

  1. 2017 Food and Health Survey: "a healthy perspective: understanding American food values." International Food Information Council website Accessed February 27, 2018
  2. Dahl WJ, Stewart ML. Position of the Academy of Nutrition and Dietetics: health implications of dietary fiber. Journal of the Academy of Nutrition and Dietetics. 2015;115(11):1861-70.
  3. Dietary fiber on the nutrition facts label. ESHA website. Accessed February 27, 2018.
  4. Notarantonio EM, Quigley Jr CJ, Vanasse T. How Health Claims on Product Packaging Influence Consumer Perceptions and Purchase Decisions. Accessed March 20, 2018.
  5. Questions and answers for industry on dietary fiber. US Food and Drug Administration website. Updated December 13, 2017. Accessed February 27, 2018.
  6. Science review of isolated and synthetic non-digestible carbohydrates. US Food and Drug Administration website. November, 2016. Accessed February 27, 2018.
  7. U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015 – 2020 Dietary Guidelines for Americans. 8th Edition. December 2015. Accessed February 27, 2018.

Review date: 3/20/18