All fibers fit — including isolated and synthesized/modified fibers. That’s the conclusion of the Institute of Medicine, the Academy of Nutrition and Dietetics and the World Health Organization/Food and Agricultural Organization of the United States (CODEX).
Dietitians usually suggest fibers found naturally in food (intrinsic fibers) as the top-priority source of fiber, but they also understand the importance of added fibers, according to a survey of 150 registered dietitians recently commissioned by Kellogg’s.
So, I was taken aback when I recently read opinions to the contrary.
“The Fiber Brigade” article in the September 2012 edition of the Berkeley Wellness Alerts (School of Public Health, University of California) refers to isolated/functional fiber as “faux fiber” and states, “The research on isolated fibers is inconsistent, and much of it is funded by manufacturers. Often, the amount of fiber added is too little to matter.”
In an online discussion, a nutrition professional stated that the health benefits of isolated/functional fibers are “questionable” and that products containing these ingredients “tend to be less healthful foods that manufacturers are trying to make look better by adding fiber.”
Another nutrition professional responded that she does not recommend foods containing added fiber because they can cause harm. Consumption often leads to excess fiber intake resulting in gastric distress and impaired mineral absorption.
These perceptions frustrate Joanne Slavin, a professor in the Department of Food Science and Nutrition at the University of Minnesota and a member of the 2010 Dietary Guidelines Advisory Committee.
“It’s not fair to bash added fiber,” said Slavin. “Most everything we eat is processed to some extent. And isolated fibers are not fake fibers.”
Noting that Americans don’t get nearly enough fiber (women need 25 grams, men need 38 grams, and the average intake is 15 grams) and that health professionals haven’t made much progress getting people to eat more high-fiber foods, Slavin believes that, although isolated fibers are not the answer, they are part of the answer.
According to the 2010 DGAC, the North American diet is low in legumes, whole grains, fruits and vegetables. In order to increase fiber intake, increased consumption of these foods is recommended and added fibers may be a realistic solution — especially to help meet fiber recommendations while staying within calorie needs.
“There’s no question that we need to add in isolated fibers,” Slavin said.”We shouldn’t depend on any one fiber; we need fiber from lots of different sources because all fibers are different and have a variety of effects. For example, inulin doesn’t lower cholesterol like oat bran but it increases bifidobacteria and lowers intestinal pH.”
Although no long-term studies investigating the effects of isolated fiber are available, many short intervention studies demonstrate beneficial physiological effects.
Add inulin to ice cream, yogurt, milk
Currently, many manufacturers use a variety of intrinsic and added fibers within their products. Adding fiber to dairy foods provides a potential source of fiber in the diet and may also improve the product’s texture and taste.
“There are many recommendations to consume low-fat dairy and since adding fiber to it makes it tastier, why not add fiber? You win twice,” said Slavin, whose research shows that the consumption of ice cream with added inulin (20 grams in one quart per day) was well-tolerated by most male subjects.
“Adding inulin to ice cream makes a fabulous vanilla ice cream,” she said.
Inulin is also an excellent choice for adding fiber to yogurt and milk, said Tonya Schoenfuss, assistant professor, dairy products technology, University of Minnesota.
“Inulin has such a good name and it’s very clean tasting with no chalkiness and no milk protein instability issues. It’s transparent, low in calories, adds to the body of the product and is a very active fiber,” Schoenfuss said.
When adding fiber to dairy foods, Schoenfuss, who was involved in the development of Yoplait Nouriche (which contained inulin), has several recommendations for processors: be sure the fiber is GRAS, is stable to the process, and that studies show it’s a prebiotic for marketing purposes.
Another consideration is how ingredients look on the label.
“With yogurt, consumers like fairly clean labels. And be sure ingredients don’t scare anyone. People may be more informed now, but in the past, they confused the word inulin with insulin,” Schoenfuss said.
Potential side effects must also be considered. When fiber is consumed at high levels or levels well above normal intake, individuals may experience bloating, flatulence, abdominal discomfort and increased laxation. To avoid unwanted side effects, consumers should increase fiber intake slowly over a period of weeks to allow the body to adjust and they also should consume plenty of fluids.
According to the “Position of the American Dietetic Association: Health Implications of Dietary Fiber” (2008), it is possible that fiber may reduce the absorption of vitamins, minerals, protein and energy if consumed in amounts above the recommended ranges. However, inulin, oligosaccharides, resistant starch and other fibers have been found to enhance mineral absorption, particularly calcium.
Increased awareness of the nature and benefits of added fiber may improve acceptance.
“Although adding fiber to dairy foods is costly for manufacturers and there are formulation issues, overall, there’s a health benefit,” said Slavin. “There may be pushback from people — probably more from the media than the scientific community — but fiber continues to be a need, so if people are using dairy as a primary source of calories, there’s a good reason to add fiber to dairy, especially if it’s a prebiotic fiber.” n
The Ins and Outs of Inulin
Inulin, a fructo-oligosaccharide (FOS), is a fiber frequently added to dairy foods, according to Deb Schulz, product manager, Cargill. The applications of inulin include adding fiber without negatively affecting flavor or texture, adding bulk, and improving mouthfeel. Therefore, it may be added in order to make a fiber claim or to reduce fat and/or calories.
Usually derived from chicory root, inulin is obtained via a water-extraction process then purified and either concentrated into a liquid or dried into a powder. This “native” form may be separated to isolate long- or short-chain inulin and then hydrolyzed further to create shorter-chain inulin. Each of these forms behaves differently.
Both inulin and FOS may be listed as ingredients, which can be confusing. Here’s the distinction: All forms of inulin (short-chain, native, and long-chain) are fructo-oligosaccharides; however, in the food industry and on the commercial side, FOS refers to shorter-chain forms of inulin.
According to Betsy Jones, research scientist with Cargill, sometimes, as in the case of medical foods, the term FOS may be used on the label in addition to the term inulin, as indication that there are short-chain and longer-chain oligosaccharides in the product to offer the benefits of a blend of soluble prebiotic fiber.
A Sampling of Dairy Products with Added Fiber
- Yoplait Light with Fiber yogurt. 5 grams fiber (inulin and modified corn starch) and 50 calories per 4-ounce serving
- General Mill’s Fiber One Cottage Cheese. 5 grams fiber (inulin, gums and carrageenan) and 80 calories per 4-ounce serving.
- Farmland Dairies Special Request Skim Plus with Fiber fluid milk. 2.5 grams fiber (inulin/chicory root) and 110 calories per 8-ounce serving