As part of the multi-year effort to amend the labels used on foods and dietary supplements to more clearly define the products’ attributes for consumers, an effort was undertaken to finally put a regulatory definition around the term ‘dietary fiber.’ Up to now, dietary fiber call-outs on labels had to do with the results of analytical tests. But FDA’s draft Dietary Fiber Guidance for the first time sought to precisely define what a dietary fiber is, at least for isolated, purified fibers.
Physiological properties of fiber
Among the criteria put forward in the guidance were the physiological effects the agency said could be associated with the ingestion of fibers. In the guidance, titled Scientific Evaluation of the Evidence on the Beneficial Physiological Effects of Isolated or Synthetic Non-digestible Carbohydrates Submitted as a Citizen Petition (21 CFR 10.30): Guidance for Industry FDA laid out the kinds of evidence companies would need to submit to prove their purified or isolated fiber meets this definition. After a literature review, the agency said only seven of 26 isolated fibers evaluated thus far meet that standard. They are: beta-glucan soluble fiber, psyllium husk, cellulose, guar gum, pectin, locust bean gum and hydropropylmethylcellulose. This leaves some prominent ingredient categories such as inulin out in the cold.
Dan Fabricant, PhD, CEO and executive director of the Natural Products Association, said that the guidance places unwarranted burdens on industry that will not result in better, safer or more healthful products for consumers. He went so far as to say that the guidance, which was released in November, is a prime example of the sort of regulation that could be eliminated under President Trump’s “2 for 1” regulation reduction initiative.
“This guidance not only creates unreasonable regulatory barriers, but also forces the food and supplement industries to spend millions of dollars jumping through more regulatory hoops while the costs are ultimately passed onto consumers. We will work with Congress and the Trump Administration to use all of the tools at their disposal, including the Congressional Review Act, to correct this flawed guidance,” Fabricant said in a statement.
“We want to see policies that are based in science,” he told NutraIngredients-USA. "Is the consumer being better protected, for example, because we moved the calories from the right side to the left side of the label? There is no evidence for that."
While not framing her objections as strongly, Andrea Wong, PhD, vice president of scientific and regulatory affairs for the Council for Responsible Nutrition, said CRN is equally concerned about certain aspects of the guidance.
“We are very concerned about the criteria they set out in the guidance that CRN believes are overly restrictive. We are after all talking about just being able to say on a label that a product contains dietary fiber. We think the guidance is overly burdensome when you think about it in that context,” Wong said.
Detailed discussion of study parameters
FDA laid out in detail in the guidance what kind of evidence could be used to prove that a certain ingredient meets the fiber definition. The agency discussed at length the questions of how control groups are delineated in studies, how the randomization process affects baseline data, where studies were conducted as a means of evaluating their relevance to the US population, etc.
“We intend to conduct this evaluation by considering the number of studies and sample sizes of each study, the relevance of the body of scientific evidence to the U.S. population or target subgroup, whether study results supporting the beneficial physiological effect have been replicated, and the overall consistency of the total body of evidence,” the agency said.
Fabricant said NPA’s comments to FDA on the guidance said that the evidentiary standards that FDA is applying amounts to a pre-approval process for isolated dietary fibers.
“We have 27 years of experience declaring dietary fibers for non-digestible carbohydrates. It is another guidance and another regulation that does not speak to safety or quality for consumers,” he said.
Advocating for fermentation as a benefit
Wong said that FDA had left out fermentation as a physiological benefit for these fibers, a ruling that she said flies in the face of the current state of evidence in the area of gut health. This is a rapidly expanding field of research, and the story on dietary fiber has expanded from its role as a pure bulking agent in building more voluminous, easier-to-pass stools into the state of the research today. That includes evidence that the metabolites of gut microbes can have a role in the gut/brain axis. These metabolites are also postulated as having effects on blood sugar management, obesity and other health indications. But CRN, in its comments, stuck to those fermentation effects that are supported by decades of research.
“The science is emerging in those other areas, but we really wanted to stick to what is well supported. At the very least you can say that butyric acid (a common metabolite of gut bacteria) is an energy source for the cells in the colon. That at least is already very well known,” she said.
Burdensome? Not by our sights
Not all agree guidance is overly burdensome. Japanese company Taiyo International, a supplier of Sunfiber, a purified form of guar gum, has been researching the ingredient for many years and now claims to have more than 100 studies relating to the ingredient. Perhaps because the company had this evidence in its hip pocket (and because it will have a competitive advantage if the guidance stands as written), the company saw the guidance as a useful addition to the marketplace.
“Taiyo was pleased that the FDA strengthened its definition of fiber and agrees that fibers should deliver actual, clinically substantiated health benefits,” said Scott Smith, vice president of Taiyo International. “While it may be burdensome for those that have simply relied on analytical methods to meet a fiber definition in the past, Taiyo feels strongly that a dietary fiber should in fact have a benefit to the consumer as a dietary fiber.
“I’m sure that for those companies that have little to no clinical support, this move has been burdensome. But, isn’t this what we want to deliver to consumers - fiber that has a benefit as a fiber?” Smith said.
Smith said Taiyo believes that all companies supplying ingredients for human consumption should be required to have evidence of the safety and efficacy for those ingredients. The presence of ingredients in the marketplace that don’t have this backing makes it more difficult for companies that have put in this work to compete.
“In collaboration with university and global partners, Taiyo conducted its research on Sunfiber in order to confirm its benefits as a dietary fiber. Yes, we believe this is the type of work that all suppliers should do,” Smith said.
Prospects for revision
NPA is seeking outright repeal of the final labeling rule based on what is says is the agency’s inconsistent treatment of fiber and the failure to conduct an economic impact analysis. On the other hand, CRN is seeking significant revision in FDA’s stance on what evidence is deemed necessary to prove an ingredient has the proper benefits to qualify as a fiber. “Throughout the scientific evaluation process, from identifying studies that assess a beneficial physiological effect to evaluating these studies and the strength of the scientific evidence, FDA describes in the draft guidance criteria that are unreasonably restrictive in the context of meeting a regulatory definition for claiming nutrient content,” the group’s comments state.
Wong said she’s hopeful that FDA will take CRN’s comments under serious consideration.
“It’s difficult to predict what they’ll do. But we have been engaging with FDA on the revision of the nutrition facts panel, and our experience there was that they did take each and every one of our comments into consideration. So we’re hopeful they will do that here, too,” she said.