What counts as dietary fiber? That's up for debate.
The Food and Drug Administration is reviewing 26 ingredients that food manufacturers use to bulk up the fiber content of processed foods to determine if there's a health benefit.
Other ingredients on the "do-these-count-as-fiber?" list include gum acacia, bamboo fiber, retrograded corn starch, and — get ready for a tongue-twister — xylooligosaccharides. Some of these fibers are extracted from plant sources, while others are synthetic.
Some critics argue that the FDA should not allow these added fibers to count as fiber on nutrition facts labels.
"The food industry has hijacked the advice to eat more fiber by putting isolated, highly processed fiber into what are essentially junk foods," says Bonnie Liebman of the consumer group Center for Science in the Public Interest.
Liebman says most people know that an apple is a healthier choice than a high-fiber brownie, but when they see high fiber counts on the label, "it may just be enough to convince them to go with the brownie."
Liebman argues a much better way to get the recommended 25 to 38 grams of daily fiber is to eat more foods that are naturally rich in fiber such as fruits, vegetables, beans and whole grains.
High-fiber diets may help protect against a range of diseases, from Type 2 diabetes and heart disease to certain types of cancer.
The FDA lists a range of health benefits linked to dietary fiber. For instance, fiber can help lower blood glucose and cholesterol levels, as well as blood pressure. Fiber can also aid laxation and bowel function, and it can promote a feeling of fullness, which may lead people to eat less.
The FDA is in the process of determining whether isolated and synthetic fibers provide a beneficial physiological effect to human health. The agency says that going forward, there must be at least one demonstrated benefit. "Only fibers that meet the definition can be declared as a dietary fiber on the Nutrition Facts label," according to this Q&A about the review process. The agency is reviewing the science.
The food industry has weighed in, pointing to the demonstrated benefits of some of these added fibers. "I think the main benefit is that they contribute to regularity and laxation," says Robert Burns, vice president of health and nutrition policy at the Grocery Manufacturers Association. Burns says most people don't consume enough fiber, so "if you can supplement [with] snack bars that people are eating, it [can] go a long way to meeting dietary recommendations."
Critics say an optimal diet is one that includes lots of whole foods such as fruits, vegetables, nuts, beans and whole grains. These foods are not only naturally rich in fiber, they also contain other beneficial compounds such as vitamins, minerals and anti-inflammatory compounds.
"Highly processed snack bars typically contain combinations of processed starch and added sugar. They're low in vitamins and minerals," says Dr. David Ludwig of the Harvard School of Public Health. "Just adding isolated fiber back in [to these processed foods] does not cover up for those nutritional deficiencies."
RACHEL MARTIN, HOST:
The Food and Drug Administration is set to decide soon on a matter that could help you rethink fiber. Yeah, we're talking about fiber. We're told to eat a whole lot more of it. It's good for us, right? But what exactly counts as fiber is up for debate. Allison Aubrey from NPR's health team joins us in the studio to explain this. Hey, Allison.
ALLISON AUBREY, BYLINE: Hey, there.
MARTIN: What is the debate about fiber?
AUBREY: Well, I think the debate is probably best illustrated with these two foods that I've brought in.
MARTIN: Look at you with food props.
AUBREY: I've got here an apple, right? An apple - this naturally contains a lot of fiber. And this is a chocolate Fiber One bar. You see them all the time in the grocery store. Kids love them. It has a lot of highly processed fiber, something that the food industry refers to as isolated fiber.
MARTIN: What does that mean to be isolated fiber?
AUBREY: Yeah, so isolated fiber is fiber that's extracted. Think of pulling it out of things like - here's some sources - chicory root, sugar cane, corn, lots of plants. So what food manufacturers do is they take all this fiber, they process it and they add it back into foods like this.
MARTIN: There's a big, old grocery bag of foods. OK, so this is...
AUBREY: (Laughter) So I'm going to dump out my bag here.
MARTIN: ...Food that has isolated fiber.
AUBREY: That's right. So I've got some white bread. I've got lots of snack bars - snack bar one, snack bar two. I've got pasta here. You'll see manufacturers splash in big, bold letters fiber...
MARTIN: Fiber, fiber.
AUBREY: ...Across the label. They want you to know there's fiber in here. I've got sugary cereal with fiber added back into it.
MARTIN: (Laughter) So, I mean, do these products - isolated or highly processed fibers, do they have any nutritional benefit?
AUBREY: Well, here's the take of one critic I spoke to. This is Bonnie Liebman. She's of the consumer group the Center for Science in the Public Interest. Listen to what she had to say.
BONNIE LIEBMAN: The problem is that the food industry has hijacked the advice to eat more fiber by putting isolated, highly processed fibers into what are essentially junk foods.
MARTIN: So they're not good for us.
AUBREY: Well, here's the thing. Food manufacturers have weighed in with the FDA. And they're saying, you know what? There is some benefit here. They're saying, you know, these foods can aid regularity or digestive health. But the experts I spoke to are not convinced. They say you don't get anywhere near the benefit that you get when you eat whole foods that are naturally rich in fiber, things like this apple or, you know, grains or beans. Here's David Ludwig. He's a professor of nutrition at the Harvard School of Public Health.
DAVID LUDWIG: Fiber's so much more than just that substance that we might read on the nutritional label. It carries along with it, in intact whole foods, a host of beneficial products like vitamins, minerals, antioxidants, anti-inflammatory chemicals. Much of that is lost in the process of refining and producing isolated fibers.
AUBREY: So, you know, the whole reason that we're told to eat high-fiber diets is because studies show that when you eat things like vegetables and beans and fruits and whole grains that you have a lower risk of certain diseases. Studies show high-fiber diets are linked to lower rates of colorectal cancer. One pointed to a lower risk of breast cancer. So it's not at all clear that just adding this isolated fiber back to processed foods would lead to the same benefits.
MARTIN: OK, so obviously, we've established that eating an apple is better for you on the fiber front. But let's just say you're never going to do that. Like, your kid's never going to eat an apple, for example. Isn't one of these bars with this so-called enriched fiber better than no fiber at all?
AUBREY: Well, that is exactly what the industry argues. Here's what Robbie Burns of the Grocery Manufacturers Association told me.
ROBBIE BURNS: Fiber is an under-consumed nutrient in the U.S. We consume less than half of what's recommended. So I look at it in a positive way that if you can supplement a snack bar that consumers are going to be consuming in any case and can add some fiber to it, it goes a long way towards helping them meet their dietary recommendation.
MARTIN: All right, what happens now? What does the FDA have to decide?
AUBREY: Well, up until now, the food manufacturers have basically been able to declare any fiber, regardless of the source, as dietary fiber on the nutrition facts panel here. And now the FDA is saying, look, there's got to be some evidence of benefit. And they're set to make a decision on this in the coming months.
MARTIN: NPR's Allison Aubrey. Thanks, Allison.
AUBREY: Thanks, Rachel. Transcript provided by NPR, Copyright NPR.