Prebiotics forge forward on gut health benefits during fiber guidance interregnum

FDA threw the world of prebiotic fibers for a loop last year when it issued a draft guidance on the evaluation of isolated or purified fibers.  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 callouts 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. In January 2017 the agency extended the comment period on the draft guidance and is currently reviewing the comments it has received.

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.

Which are really fibers, and which are wannabes?

The issue for the agency seems to have been the significant proliferation of these ingredients in the market. Intrinsic fibers, such as wheat bran, corn bran, oat bran and others, clearly meet FDA’s definition.  But they can be challenging to formulate with, which is why ingredient developers stepped into the breach with isolated and purified fibers. These functional carbohydrates are often available as bland-tasting, slightly sweet syrups with friendly hydroscopic and mouthfeel properties that go easily into bars or nutritional drinks.  So a company can claim fiber content, which many consumers are looking for, without having to jump through many formulation or manufacturing hoops. But questions have been raised within the industry about some of these ingredients, such as certain IMOs (isomaltooligosaccharides) that are alleged to be only indifferently bound together via enzymatic processes.  Are these really dietary fibers as consumers understand them?  Or are they more like big houses of cards made up of sugar molecules, just waiting to quickly fall apart in the digestive tract?  That’s what FDA seems to want to determine. 

Few companies that have ingredients in this limbo condition are willing to speak on the record about the prospects for their products. Many manufacturers have submitted dossiers on their prebiotic ingredients to FDA and the evaluation process is ongoing.  But Dr Alex Schauss, PhD, principal in the consulting firm AIBMR, said companies with these kinds of ingredients should in the interim take heart, assuming they have data to back their products in the first place.

“What we tell clients is: Build your portfolio.  Don’t be scared by the restrictions that FDA imposes. Build the science;  I think that’s what FDA is saying.  Show us the data,” Schauss told NutraIngredients-USA.

Differing impact for foods, supplements

Steve Hanson, an executive with Prenexus Health, a company that has developed a prebiotic called XOS95 from high fiber sugar cane, said the issue is less problematic for dietary supplements than it is for foods.  Fiber is not one of the callouts on a Supplement Facts panel as it is on a Nutritional Facts panel for foods.

“You can talk about these ingredients as a prebiotic ingredient.  You can’t call them a fiber at the moment,” he said.

“It’s less significant in the supplement industry. You can potentially call the prebiotic material exactly what it is.  Consumers are willing to look at dietary supplements differently than they do foods.  You can put an ingredient on the label that has a name like fructooligosaccharide or xylooligosaccharide and still engage the consumer,” he said.

“For foods the effect of the  guidance is significant when consumers are tying to get more fiber in their diets and manufactures are trying to make that claim on their labels,” Hanson said.