Marketing products for digestive maladies (such as IBS, bloating, diarrhea, etc.) can be difficult, when the public is still becoming educated on the subject. Ingredients such as soluble and insoluble fibers, inulin, prebiotics and probiotics, live cultures and resistant starches can be incorporated into foods to help the more than 70 million Americans who suffer from bowel disorders feel better and healthier.

Consumer education plays a key role in the marketing and sales of most condition-specific products. For some of these items--like those for heart or bone health, the message to consumers is relatively clear. Educating consumers on digestive health, however, has numerous hurdles.

The highest of these is simply that it is an uncomfortable topic. For most people, gastrointestinal disorders are not the subject of a friendly conversation with anyone other than their doctor. The vocabulary alone, which includes diarrhea, constipation and Irritable Bowel Syndrome (IBS), to name a few conditions, can send people running in the other direction. The terms free radicals, osteoporosis and LDL cholesterol are simple when contrasted to many long Latin binomial names, such as Lactobacillus acidophilus and Streptococcus thermophilus, which are hardly pronounceable to most, never mind memorable. 

Other scientific terms, such as short-chain fatty acids, fructo-oligosaccharides and the confusing terms “prebiotics” vs. “probiotics” are not much easier to understand and retain. Finally, with the ubiquitousness of antibacterial products in the market, the term “bacteria” has only negative connotations. As a result, the term “good bacteria,” which is really at the heart of proper digestive health, sounds like an oxymoron to most consumers.

Unfortunately, there are millions of people who need a more-than-cursory education on digestive health. According to the National Digestive Diseases Information Clearinghouse, over 70 million Americans suffer from some type of digestive disorder that interferes with work and life. The International Foundation for Functional Gastrointestinal Disorders (IFFGD) reports that 25% of the U.S. population suffers daily from a functional gastrointestinal (GI) malady. These ailments are defined as disorders that are a result of an altered physiological function (the way the body works) rather than an identifiable structural or biochemical cause. Therefore, functional GI illnesses are often very difficult to diagnose by examination, X-rays or laboratory tests. They are also the most common types of digestive complaints in society, and the category includes afflictions such as IBS, dyspepsia, chronic diarrhea and constipation. They are so common that, according to the IFFGD, workplace absenteeism due to functional digestive disorders is second only to the common cold. In fact, that common cold might also be a result of a poorly functioning digestive system.

While the primary functions of the GI system are to digest food and absorb nutrients, a little-known fact is that the GI system is the largest immune system organ in the body and home to about 75% of our body's immune cells. The benefits of a highly functioning digestive system are surprisingly extensive--from supporting the nervous system (our gut contains more neurotransmitters than our brain) to preventing allergies to reducing the risk of certain cancers.  

These are the salient statistics that support the potential for explosive growth of digestive health products. Armed with an abundance of good science and improved technology for stabilizing, incorporating and processing digestive health ingredients into more types of foods, food scientists can now transcend the usual food matrices for digestive health ingredients. The traditional products, such as yogurt and other cultured-milk foods, can soon be joined by highly efficacious products that not only improve digestive health, but also overall health

Probiotics--The “Right” Bugs

Although yogurt products are taking up more and more shelf space at the supermarkets, and the term “live cultures” is prominently displayed on their labels, most consumers do not know exactly what ingredients in yogurt make it such a healthy food. These live cultures are various strains of “good bacteria” that also are found living comfortably and productively in the gut. This relationship is the quintessential example of symbiosis, as these good bacteria provide enormous benefits to people, their host. These microorganisms perform a number of essential functions, the most important being the fermentation of indigestible carbohydrates, the by-product of which is the production of short-chain fatty acids (SCFAs). SCFAs have been correlated with a reduced risk of IBS, inflammatory bowel disease, cardiovascular disease and certain cancers. SCFAs also affect blood glucose and lipid levels; decrease the pH of the gut, improving mineral absorption; and help regulate immune responses.

“Good bacteria” may also inhibit the growth of “bad” bacteria. Many factors, such as a poor diet, antibiotic use, stress, age and lack of exercise, can upset the balance between the beneficial and harmful bacteria, resulting in many common digestive complaints. Re-establishing an optimal microflora balance can be achieved by consuming “good bacteria,” in the form of probiotics from food products or supplements.

The Food and Agriculture Organization of the United Nations (FAO) defines probiotics as “live microorganisms, administered in adequate amounts, which confer a beneficial health effect on the host.” For the product developer, the biggest challenges in using probiotics are the “live” and “adequate amount” points of this definition, as these bacteria are not terribly stable. Efficacy can only be achieved if the probiotics survive through processing, shelflife and, finally, the stomach’s pH level. Traditionally, dairy products have been used to deliver probiotics because of a more optimal pH for shelflife stability; they also buffer stomach acid, increasing the viability of the bacteria once it is in the gut. 

Improved probiotic integrity means there will be new food applications for their delivery.  From microencapsulation technology to inoculation methods that allow these bacteria to be added after heat treatment, manufacturers of probiotics are patenting ways to resolve the stability obstacles. In addition, research into novel probiotic strains with improved stability has also led to numerous patents. One example is the spore-forming bacteria Bacillus coagulans, which remains dormant and does not start growing until it reaches the body’s intestinal tract. All this innovation has led to the use of probiotics in new applications such as bars, baked goods, juices and even chocolate. 

Another vital consideration when formulating with probiotics is the choice of bacterial strain. Bacteria are categorized by genus, species and strain names. The sheer volume of information of the various species and strains can be overwhelming, even for microbiologists. Various strains of bacteria from the genera Lactobacillus and Bifidobacterium are most commonly used in probiotic products, but it is still not completely clear which strains elicit which health benefits. Current research in this area is also looking beyond these standard genera. One example of such research reported that strains from Streptococcus and Leuconostoc were the most potent inducers of cytokine activity, which is involved in regulating the immune response.1 

According to www.USprobiotics.org, research published on one strain of probiotic bacteria does not transfer to another strain of the same species. In fact, strains of the same species may have completely different probiotic properties. Many manufacturers of probiotics have developed clinically tested, proprietary “designer” strains, or blends which target specific health benefits. Manufacturers are also performing research in specific food applications. For instance, one recent study reported that Lactobacillus acidophilus L10, when added to cheddar cheese, resulted in the formation and release of angiotensin converting enzyme (ACE)-inhibitory peptides, which may improve blood flow and blood pressure.2 Such research adds yet another layer of complexity for the formulator, because the positive results of using one strain in one particular food application are not necessarily guaranteed in others.

Fiber: The Tried-and-true and the Up-and-coming

Fiber, both soluble and insoluble forms, is the most familiar ingredient for digestive-friendly foods. The majority of consumers are aware that dietary fiber is important for aiding regularity. Thanks to the FDA-approved health claims for certain forms of fiber such as whole grains, beta-glucans from oat and barley, and psyllium, consumers also know fiber is heart-healthy. There are more unfamiliar fibers also entering the market.  One new player is glucommanan, a soluble fiber from the Asian konjac plant. Supplementation of 4.5g/day of glucommanan was reported to work as a natural laxative by increasing stool bulk, promoting growth of lactic acid bacteria by decreasing pH and increasing fecal SCFA concentrations. 3  Vegetable gum fibers, such as acacia fiber and guar gum, also relatively new to the market, are often marketed as effective in the treatment of IBS.

Prebiotic Fibers

Many of the next generation of fibers also have a prebiotic property, a concept which basically means they feed the good bacteria. In addition to the established health benefits of fiber nutrition, prebiotic fiber is fermented by the good bacteria in the colon, producing those health-promoting SCFAs. By acting as fodder for only the good bacteria, prebiotic fiber stimulates their growth and, therefore, can result in the same health benefits as probiotics.

The prebiotic terminology is almost as confusing as that of probiotics. Prebiotics are found naturally in plants, but many commercial ingredients are further processed, with each level of processing allowing for lower recommended dosages. One unprocessed prebiotic fiber is inulin, a heterogenous mix of mostly fructose polymers of various lengths, found in plants such as chicory and Jerusalem artichoke. Enzymatic hydrolysis of inulin produces oligofructose, which are fructose polymers of smaller chain length (degree of polymerization <10). Inulin and oligofructose have been well-studied, and doses of 5-10g have produced dramatic, positive shifts in the composition of microflora in humans and can be used in the treatment and prevention of numerous intestinal disorders and diseases. 4  Natural fermentation of beet or sugar cane produces short-chain fructo-oligosaccharides, which are fructose polymers with a maximum chain length of only five units. These polymers are considered a more pure form of prebiotic fiber, with potential for greater health benefits, including enhanced immunity, 5,6 and clinically proven, improved calcium absorption, with as little as a 3g/day dosage. 7  There are also commercially available mixtures, such as inulin enriched with oligofructose, that have clinical studies supporting increased calcium absorption and improved bone density. 8,9

Prebiotic fibers may also contain different sugar polymers, such as arabinogalactans extracted from the larch tree. Arabinogalactans have been shown to increase the production of SCFAs, and in vitro studies have also indicated they may stimulate the immune system. 10  A recent clinical trial using a novel mixture of galacto-oligosaccharides from milk reported that supplementation of 3.6-7g per day selectively stimulated growth of Bifidobacteria in the gut, as well as inhibited the adhesion of bad bacteria to the gut wall. 11 Other prebiotics include polydextrose and certain polyols.

Some of the most exciting prebiotic research is the area of “synbiotic supplementation,” where prebiotics are combined with probiotics. The E.U.-sponsored Syncan Project evaluated the potential role of a combination of oligofructose-enriched inulin and Lactobacillus rhamnosus GG and Bifidobacterium lactis Bb12 in colon cancer risk. The clinical trial was conducted in colon cancer patients and polypectomized patients (those who experienced the removal of polyps). This synbiotic supplementation had numerous positive effects, including significant changes in fecal flora and a reduction in colorectal cell proliferation, which is linked to a high risk for colon cancer. The supplementation also increased secretion of interleukin 2 (an immune system signalling molecule) in the polypectomized patients and increased the production of interferon (a cytokine with antiviral, immunoregulatory and anti-tumor properties) in the cancer patients. 12 Another clinical study, using a combination of oligofructose and three probiotic strains, resulted in both improved gastrointestinal health and improved overall oxidative status of the volunteers. 13

Resistant Starches

Another form of indigestible carbohydrates is called resistant starch, because it resists digestion in the small intestines. Resistant starches are found in foods such as beans, corn, green bananas and unprocessed whole grains and are considered a third type of dietary fiber, delivering the benefits of both soluble and insoluble fibers. Natural resistant starch may also have prebiotic properties: by producing SCFAs through their fermentation in the colon. Replacing flour with a natural resistant starch may provide added health benefits. A clinical study published in April reported that healthy subjects who ate bread enriched with resistant starch and barley fiber had improved glucose tolerance, lower inflammatory markers and increased satiety. 14 Animal studies have also linked resistant starch to reduced colonic and systemic immune reactivity. 15

Will all this high-quality science translate into growth of digestive health products? Definitely. A successful digestive health product should be noticeably efficacious, offering consumers quick relief from their suffering. The number of clinical trials supporting the use of digestive health ingredients is providing formulators crucial parameters, such as the proper dosage, so that the product really works and consumers will continue to buy it. This is one of the main reasons the digestive health market continues to grow and is considered one of the hottest trends in the condition-specific market category, especially for the functional food industry.

One challenge will be reversing the taboo about publicly discussing digestive issues; another is educating consumers about digestive disorders. Perhaps some creative euphemisms will help consumers be rid of this negativity. After all, the California Dried Plum Board single-handedly changed the word for “prunes” to “dried plums” for a similar reason.  NS

References

1 Kekkonen RA, et al. 2008. Probiotic Leuconostoc mesenteroides ssp. cremoris and Streptococcus thermophilus induce IL-12 and IFN-f× production. World J Gastroenterol. 14:1192-1203.
2  Ong L, et al. 2008. Influence of probiotic Lactobacillus acidophilus and L. helveticus on proteolysis, organic acid profiles, and ACE-inhibitory activity of cheddar cheeses ripened at 4, 8, and 12 degrees C. J Food Sci. 73:M111-M120.
3 Chen HL, et al. 2006. Konjac acts as a natural laxative by increasing stool bulk and improving colonic ecology in healthy adults. Nutrition. 22:1112-9.
4 Niness KR. 1999. Inulin and oligofructose: what are they? J Nutri. 1999. 129: 402S-1406S.
5 Adrogony V, et al. 2007. Effects of dietary scFOS on immunoglobulins in colostrums and milk of bitches. J Anim Physiol Anim Nutr (Berl). 91:169-174.
6 Nakamura Y, et al. 2004. Dietary fructo-oligosaccharides up-regulate immunoglobulin. A response and polymeric immunoglobulin receptor expression in intestines of infant mice. Clin Exp Immunol. 137:52-58.
7 Uenishi K, et al. 2002. Effects of malt drink containing fructo-oligosaccharides on calcium absorption and safety of long-term administration. The Japanese Journal of Nutrition and Dietetics. 60:11-18.
8 Holloway L, et al. 2007. Effects of oligofructose-enriched inulin on intestinal absorption of calcium and magnesium and bone turnover markers in postmenopausal women. Br J Nutri. 97:365-72.
9 Abrams SA, et al. 2007. Young adolescents who respond to an inulin-type fructan substantially increase total absorbed calcium and daily calcium accretion to the skeleton.  J Nutri. 137:2524S-2526S.
10 Kelly GS. 1999. Larch arabinogalactan: clinical relevance of a novel immune-enhancing polysaccharide. Altern Med Rev. 4:96-103.
11 Depeint F, et al.  2008. Prebiotic evaluation of a novel galacto-oligosaccharide mixture produced by the enzymatic activity of Bifidobacterium bifidum NCIM 41171, in healthy humans:  a randomized, double-blind, cross-over, placebo-controlled intervention study. American Journal of Clinical Nutrition. 2008. 87:785-791.
12 Rafter J, et al.  2007. Dietary synbiotics reduce cancer risk factors in polypectomized and colon cancer patients. Am J Clin Nutr. 85:488-96.
13 Saulnier DMA, et al.  2007. Effects of a symbiotic on biomarkers of oxidative stress and fecal microbiota in healthy adults: results of a cross-over, double-blind placebo-controlled trial. Proc Nutr Soc. 66:101A.
14 Nilsson AC, et al. 2008. Including indigestible carbohydrates in the evening meal of health subjects improves glucose tolerance, lowers inflammatory markers, and increases satiety after a subsequent standardized breakfast. J Nutr. 138:732-9.
15 Nofrarias M, et al. 2007. Long-term intake of resistant starch improves colonic mucosal integrity and reduced gut apoptosis and blood immune cells. Nutrition. 23:861-70.


Although yogurt products are taking up more shelf space at the supermarkets,  consumers are only gradually becoming aware of the nature of the health benefits of pre- and probiotic ingredients.
© iStockphoto/Anna Grzelewska

On the Web: DIGESTIVE HEALTH

* http://digestive.niddk.nih.gov/index.htm -- National Digestive Diseases Information Clearinghouse--a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), NIH
* www.usprobiotics.org -- A non-profit research and education web site sponsored by the California Dairy Research Foundation and Dairy Food Culture Technologies