Digestive health is a rising star among functional foods, capturing 68% of the market for approved functional foods in Europe and 64% in Japan last year, according to AC Nielsen (New York City). Among all of the digestive health products, fiber may shine the brightest. In the United States, functional foods bearing a fiber claim raked in $2.9 billion from July 2006 to July 2007, a 13% increase.
In fact, fiber's presence has increased markedly over the past few years, posting a 59% gain compared to four years ago. Even though the Institute of Medicine (Washington, DC) suggests that people eat 14 g of fiber for every 1000 calories of food, most Americans don't come close to the average recommended daily intake, about 38 g for men and 25 g for women. To get their fill, Americans have been turning more and more to several varieties of fiber.
Americans get most of their insoluble fiber from whole grains, such as wheat, barley, and brown rice. However, other plant-based foods, including nuts, carrots, cucumbers, and tomatoes, also provide insoluble fiber. Insoluble fiber, as its name suggests, does not dissolve in water and passes quickly through the digestive tract.
Bran, the hard outer region of whole grains, is a common source of insoluble fiber that is often found in breakfast cereals and baked goods. Most consumers think of wheat or oats when they think of bran, but other grains like corn can also be plentiful sources. One corn-based ingredient, for instance, Grain Processing Corp.'s (Muscatine, IA) TruBran corn bran, is composed of about 85% insoluble fiber. Manufacturers can add the golden-brown ingredient to baked goods and nutrition bars by mixing fine or coarse bran particles into flour.
Another source of insoluble fiber is chia (Salvia hispanica L.), a member of the mint family. Despite their association with the kitschy Chia Pet line of novelty items, chia seeds offer impressive amounts of antioxidants, fiber, and the omega-3 alpha linolenic acid (ALA). According to a small pilot study by Canadian researchers that was published online in the journal Diabetes Care on August 8, 2007, chia fiber may improve cardiovascular risk factors and glycemic control in people with well-controlled type 2 diabetes. The single-blind, crossover trial used Salba, a grain cultivated by AgriSalba (Ica, Peru) that consists of 31 g of insoluble fiber per 100 g.
One example of a chia fiber product is ChiaMax, a dietary supplement ingredient unveiled in March at Natural Products West in Anaheim, CA. The ingredient contains 48 g of fiber and 30 g of protein plus 6 g of self-stabilized ALA per 100 g. "For years, high-protein, low-carbohydrate foods have been favorites with health- and weight-conscious consumers. Even hotter today are trends toward increased dietary fiber and omega-3s by consumers who want to address energy management, heart health, and glycemic concerns," says Rudi Moerck, PhD, president of ChiaMax manufacturer Valensa International (Eustis, FL). "With ChiaMax, food producers can take advantage of these health and eating trends with a single ingredient."
Gums Offer a Range of Benefits
While oats, wheat, and corn command much of the limelight when it comes to digestive health, there is another class of high-performing ingredients that is sometimes overlooked: gums.
Manufacturers can use gums as a fiber source and as a way to modify the texture, mouth feel, or shelf life of foods. Common gums include fruit-based pectin, yam-derived konjac, and the carob extract locust bean gum. Other popular gums include gum arabic, an extract of the acacia tree, and guar gum, which comes from an Indian legume. In addition, hydrocolloid gums provide many of the same benefits as other sources of dietary fiber while greatly modifying a food's organoleptic properties.
In February, Gum Technology Corp. (Tucson, AZ) launched a new gum ingredient, Fenuxan. As the product's name suggests, Fenuxan combines both fenugreek and xanthan gums. The combination offers a stronger stabilizing system than either ingredient alone.
"Gums are a very interesting source of fiber in that there is the added benefit of being functional as a texturant, as well as contributing fiber to the food system," says Allen Freed, president and CEO of Gum Technology Corp.
Freed adds that gums typically have an 85% or greater fiber content, and studies have shown that many gums may help balance cholesterol and blood sugar.
"Even if the gum is used primarily for its ability to control rheology, there is the contribution of fiber and usually a friendly label statement, since most gums are all-natural and the consumer is conditioned to seeing them on the label," Freed says.
Soluble fiber, on the other hand, does dissolve in water, forming a gel that slows digestion and enhances the body's ability to absorb nutrients from food. Common sources of insoluble fiber include oatmeal and oat bran, beans and legumes, and fruit, such as berries, apples, and pears.
"Unlike insoluble fiber, which passes through the intestinal tract as bulk, soluble fiber can interact with other bodily processes to produce a variety of health benefits," says Kristina Williams, vice president of marketing and sales at Natraceutical Canada Inc. (Edmonton, AB, Canada), which markets the beta-glucan fiber ingredient ViscoFiber. Those benefits may include improved cholesterol, glycemic response, glucose management, and satiety.
Williams adds that the viscosity created when soluble fiber forms a soft gel in the stomach accounts for its activity. "FDA and several researchers have recognized that viscosity formation is a key property for the physiological effects of consuming soluble fiber," Williams explains. "This has also been confirmed in a pilot study comparing ViscoFiber to a low-viscosity beta-glucan product."
Natraceutical Canada manufactures ViscoFiber from oats using a patented fractionation process. The resulting material contains up to 50% soluble fiber, with 4 g providing the same amount of soluble fiber found in 6 cups of oatmeal. Moreover, a recent study published in the December 2007 issue of the Journal of Medical Food found that ViscoFiber may have a beneficial impact on satiety, an important component of weight management. In the study, researchers from the Pennington Biomedical Research Center (Baton Rouge, LA) gave 7 overweight volunteers 4 g of ViscoFiber per day for 16 weeks and measured satiety-related hormones such as peptide YY (PYY) and glucagon-like peptide 1 (GLP-1).
"The study showed that ViscoFiber, combined with a diet and lifestyle program, gave a safe, statistically significant weight loss over the course of 16 weeks," Williams says. "There was also a decrease in hunger and a statistically significant increase in satiety as well as in the gut hormones that may contribute to weight loss and satiety." Williams adds that the study's principal investigator, Frank Greenway, MD, concluded that ViscoFiber may be more potent than other forms of fiber when it comes to satiety and weight management.
A key source of soluble fiber besides oats is barley. Barley is actually an excellent source of fiber because it contains both soluble and insoluble fiber throughout the grain. Therefore, barley ingredients can remain high in fiber even when the grain's outer layers are removed.
In February, FDA revised an existing health claim linking consumption of soluble fiber to a reduced risk of heart disease, expanding the definition of soluble fiber to include barley betafiber, a concentrated, low-viscosity source of beta-glucan. A sample health claim might be worded: "Diets low in saturated fat and cholesterol that include 3 g of beta-glucan soluble fiber from barley betafiber may reduce the risk of heart disease. One serving of [insert name of food] provides [insert number] of grams of this soluble fiber."
FDA's move is likely to benefit Cargill (Minneapolis), currently the only producer of barley beta-glucan concentrate that qualifies for FDA's health claim. Cargill petitioned FDA to update the health claim, which reflects new research showing barley betafiber may improve cholesterol levels.
"Cargill is pleased that FDA has extended its soluble fiber health claim to include barley betafiber," says William Rock, barley betafiber product manager at Cargill. "This is a significant step in Cargill's drive to commercialize new products with high relevance to consumers, capitalizing on the increasing demand for heart-healthy products."
The beneficial effects of insoluble and soluble fibers are fairly well known. Less well known are the effects of prebiotic fibers, short-chain carbohydrates that nurture the growth of beneficial bacteria and inhibit the growth of harmful bacteria by lowering the pH in the large intestine. Some research indicates that in addition to promoting digestive health, prebiotics enhance the absorption of minerals such as calcium and provide a boost to the immune system. Moreover, prebiotics also impart sweetness and texture to foods, making them useful additions to dairy products and baked goods. Common prebiotics include inulin and oligofructose.
One of the most unusual sources of prebiotic fiber is arabinogalactan, an extract from the larch tree. According to Lonza (Allendale, NJ), which supplies an arabinogalactan ingredient called FiberAid, the extract contains a 6:1 ratio of the sugars galactose and arabinose.
"Prebiotic fibers have many of the same benefits as traditional fibers, but they also provide additional benefits," says Bryan Rodriguez, technical and applications manager at Lonza. "For example, they increase beneficial cell populations that interact positively with the immune system, such as lactobacilli, bifidobacteria, and total anaerobes. Additionally, prebiotic fibers increase the production of short-chain fatty acids and decrease fecal ammonia levels."
Rodriguez adds that some, but not all, prebiotic fibers can cause flatulence and bloating. "Due to its slow fermentation, FiberAid does not produce these side effects,"Ã¢ÂÂRodriguez says. "Essentially, by using FiberAid, consumers get the prebiotic effects without the side effects."
FiberAid also functions as an emulsifier, humectant, processing aid, and stabilizer that retains moisture and extends shelf life in baked goods, Rodriguez says.
A less unusual source of prebiotic fiber is corn. Last July, Tate & Lyle (London) announced the launch of Promitor, a corn-based, soluble prebiotic fiber that has a low glycemic impact. Promitor can replace traditional sweeteners without affecting the texture of foods. In addition, Promitor contains only 2 kcal per gram.
"Our goal was to deliver to our customers and consumers high levels of fiber fortification in new product areas, without any impact on taste or texture," Jim Miller, Tate & Lyle's director of product management for the Americas, said last July during the product's launch. "With its exceptional clarity, low viscosity, and process stability, Promitor soluble corn fiber can be used in products where people wouldn't expect to find fiber, such as salads and dressings, or clear beverages. This will enable consumers to incorporate more fiber into their everyday diet."
Roquette's (Lestrem, France) Nutriose, another low-calorie soluble prebiotic fiber, offers similar health and functional benefits. Derived from non-GMO wheat or corn, Nutriose dissolves completely in water without imparting an off taste. The ingredient also withstands acidic pH levels, ultrahigh-temperature processing, and prolonged pasteurization and sterilization, says Jeff Felgar, product manager at Roquette America Inc.
"Apart from its use in providing added fiber, Nutriose also works well in sugar reduction," Felgar says. "Nutriose is sugar free and noncariogenic, and it has a low insulinemic index of 13, making it a great ingredient in formulations for diabetics." Felgar adds that the ingredient, which is used in products ranging from nutritional drinks and bars to chocolates and baked goods, is well tolerated in the digestive tract and has a dietary tolerance of more than 45 g per day and a glycemic index value of 25.
A third prebiotic fiber is GTC Nutrition's (Golden, CO) NutraFlora, a short-chain fructooligosaccharide (FOS) made from non-GMO beet or cane sugar. NutraFlora is only about 30% as sweet as sugar but it dissolves completely in water. Short-chain prebiotic fibers are versatile from a functional standpoint, says GTC's food science manager, Laurie Scanlin, PhD.
"Functional benefits offered by this ingredient solution include flavor and sweetness enhancement, mouth feel and texture improvement, and flavor masking," says Scanlin. "Because NutraFlora is 95% short-chain FOS, both health and functional benefits can be realized using as little as 1.1 gram per serving."
Consumers are increasingly looking to maintain and improve their well-being through their dietary habits, adds Scanlin. "They are more interested in learning how novel ingredients are being used in today's better-for-you foods," Scanlin says. "In the past couple of years, consumer awareness about the many health benefits of probiotic fibers, specifically NutraFlora short-chain FOS, has risen sharply. This is in large part due to the availability of more prebiotic-enriched food, beverage, and supplement products-many of which are cobranded with the NutraFlora seal."
Tim van der Scraelen, marketing and communications managerÃ¢ÂÂatÃ¢ÂÂBeneo-Orafti (Tienen, Belgium), concurs that interest in prebiotics is growing, even though higher energy and raw material costs have raised prices for prebiotic ingredients.
"Consumers are willing to pay a price premium for products with added health benefits," says van der Scraelen. "Manufacturers remain committed to developing well-balanced food products that offer consumers additional health benefits like those related to gut health. Consumers truly understand the importance of a healthy digestive system and will spend accordingly to reap the benefits."
To capitalize on the growing consumer awareness of prebiotics, Orafti, which supplies inulin and oligofructose, has submitted five health claim petitions to the European Commission, according to Wim Caers, Orafti's manager of regulatory affairs. Proposed claims include: promotes a balanced microflora, promotes digestive health, increases calcium absorption leading to increased bone strength, and stimulates your body's natural defenses.
Found in bananas, beans, potatoes, and many common foods, resistant starch is a unique fiber with prebiotic and other salutary properties. Unlike other starches, which are digested in the small intestine, resistant starch passes through the small intestine undigested until it reaches the large intestine, where it acts as a normal dietary fiber. At an October 2007 conference organized by the food issues think tank Oldways (Boston) and National Starch Food Innovation (Bridgewater, NJ), researchers described several potential health benefits of resistant starch, including weight control and blood sugar balance.
According to Michael Keenan, PhD, associate professor of Louisiana State University's division of human nutrition and food, short-chain fatty acids produced when resistant starch is fermented stimulate the production of the satiety-related hormones GLP-1 and PYY. Moreover, at the conference, Janine Higgins, PhD, assistant professor at the University of Colorado at Denver's Center for Human Nutrition, presented data indicating that resistant starch lowers postprandial glucose and improves insulin sensitivity.
National Starch's Hi-Maize resistant starch is easy to add to baked goods and is supported by more than 120 studies and clinical trials, according to the company. Hi-Maize can also be combined with other prebiotic ingredients. For instance, GTC supplies a combination NutraFlora and Hi-Maize blend for low-moisture products and mildly processed higher-moisture foods.
"The NutraFlora Plus Hi-Maize blend delivers the advantages of both soluble and insoluble fibers, and numerous health benefits offered by these functional ingredients," says GTC's Scanlin.
Fibers are commonly described as soluble or insoluble, but that's not the only way to think about them. Fibers can be classified by their physical properties (e.g., soluble versus insoluble, viscous versus nonviscous, etc.), effects on health (e.g., prebiotic, low glycemic, etc.), chemical structure (e.g., FOS, beta-glucans, etc.), or even their origin (e.g., wheat bran, corn bran, oat bran, etc.).
Significantly, fibers play important roles in both health and food processing. Unfortunately, most Americans still have a long way to go before they meet the recommended daily targets of 38 g for men and 25 g for women. However, with rising awareness among consumers and a plethora of new high-fiber products, things could be changing for the better.