Functional Gut Support

“Beneficial bacteria” used to sound like a contradiction in terms; but these days, the benefits of probiotics and prebiotics are more well-known. However, many consumers still think of these health-promoting ingredients as coming from yogurt alone. The truth is, pro- and prebiotics and their benefits are rapidly becoming available in a wide variety of delivery systems, from functional foods and beverages to efficacious dietary supplements.

Probiotics are microorganisms that have demonstrated beneficial effects on human health, working in the gastrointestinal (GI) tract to enhance nutrient uptake, promote digestive function and bolster immunity. “Sometimes it’s embarrassing to talk about our colon, bowel movements, intestinal gas, and other things associated with expelling waste material from our bodies,” said Ron Udell, president of Soft Gel Technologies Inc. (SGTI). “Yet these bodily functions are very important for the crucial role they play in our health. Many health care practitioners believe all health issues are related in some way to the process of digestion. Probiotics play a crucial role in improving digestive health, which, in turn, is interconnected to every function in our bodies.”

There are hundreds of kinds of probiotics colonizing the GI tract, including the best-known family strains of Lactobacillus and Bifidobacterium. These helpful bugs have had a symbiotic relationship with humans for thousands of years. Unfortunately, modern industrialization, including surgical childbirth, pasteurized foods, cleaner homes, extensive use of antibiotics and other factors have altered the internal ecology of the body, as probiotics are displaced by other less-beneficial microorganisms. This change in human intestinal microflora may have many adverse effects on overall health; studies suggest it has contributed to the rising incidence of autoimmune diseases, for example (Med Hypotheses. 2007 Aug 24; [Epub ahead of print]).

Within the body, probiotic organisms function on a number of levels to promote well-being. They appear to restore natural gut function following post-infectious irritable bowel syndrome; (D ig D is. 2007; 25(3):241-4) and beneficially impact hy pertension, immunomodulation, serum lipid profiles and postmenopausal disorders (Nutr Rev. 2007;65(7):316-28). Ingestion of probiotics appears to also keep the body in optimal health (Int J Food Microbiol. 2006;107(2):104- 11). These and other health benefits have played into the growing commercial market for such ingredients, and even researchers have suggested improved technology will offer “improved physiology and functionality [of probiotics] in the gut and to enlarge the range of commercially available probiotics, as well as expanding product applications” (Curr Opin Biotechnol. 2007;18(2):176-83).

Working in concert with probiotics in the gut are prebiotics, nondigestible, beneficial ingredients that selectively stimulate the growth or activity of bacteria in the GI tract, thus improving host health. “The colon is home to more than three pounds of bacteria,” said Cristina Munteanu, food applications specialist for GTC Nutrition. “The purpose of a prebiotic is to foster the growth of bacterial species that benefit health through their growth, activity and metabolic products.”

Chandani Perera, project coordinator of technology and applications development with Roquette America Inc., added: “Prebiotics help the growth of a healthy micro-flora in the gut by providing the energy source. The ability of gut microflora to utilize different prebiotic ingredients depends on the chemical structure and relative chain length of the prebiotic ingredient.”

Those differences can be considerable. “When comparing prebiotics, the glucose at one end of the chain and the short-chain length are extremely important factors to the fermentation profile and ingredient functionality,” Munteanu said. “The chemical structure and relative chain length of a prebiotic will determine how easily it can be used by probiotic bacteria.”

Oligosaccharides dominate the prebiotic category, including fructooligosaccharides (FOS), inulin, arabinogalactans and lactulose. In addition to enhancing the benefits of probiotics, prebiotics can also improve absorption of minerals. NutraFlora® (from GTC Nutrition) short-chain FOS (scFOS®), for example, was shown to have beneficial effects on mineral absorption and gut health via fermentation in the intestines (Bifidobacteria Microflora. 1990;10(1):65-79) (Am J Clin Nutr. 2004;80:1658-64). This fermentation process produces short chain fatty acids (SCFAs). “SCFAs promote protective effects on the gut and host, such as increased gut integrity enhanced immunity through pathogen inhibition, improved normal bowel function, and improved nutrient metabolism and absorption, without adverse effects,” Munteanu said.

ORAFTI offers oligofructose, inulin and a combination of the two in its Beneo™ line. Tim Van der Schraelen, marketing and communication manager with ORAFTI Active Food Ingredients, called out some of inulin’s specific benefits: “Inulin is not digested, but reaches the colon intact where it is selectively fermented in the colon by the good bacteria. This results in an improved transit. It also has a prebiotic effect and thus creates a healthier gut flora. An improved gut metabolism also provides better calcium absorption which ensures healthier bones.”

Other specialty offerings include the NUTRIOSE® line of soluble fiber sourced from corn or wheat, and SGTI’s xylo-oligosaccharide, which features oligosaccharides containing beta-linked xylose units.

Storage, Safety, Efficacy

While consumers are more interested in this category of health-promoting ingredients, probiotics and prebiotics do bring particular challenges to the product development bench-top.

Kristin Gross, strategic sales manager at Chr. Hansen, explained probiotics are sensitive, and they generally are not easily incorporated in functional foods and beverages outside of dairy applications. “This presents an obvious challenge for formulators as they need to ensure that the probiotic strains in their product remain viable through the end of shelf life and meet stated label claims,” she said, noting shelf and gastric stability have historically been a challenge for these products, with few established stabilization technologies. “Fortunately, new technologies are developing to enhance the stability of probiotics in new applications.”

Probiotics are notoriously difficult to store, and lower-grade ingredients that might have started their shelf-life with “50 billion bugs” can be nearly dead by the time the ingredient is ingested by the end-user. Strain selection and efficacy for a desired health benefit also come into play.

Ingredient selection thus becomes a balancing act, with formulators looking for easy storage, strong efficacy and more. A thorough knowledge of the abilities of the microorganism to survive the manufacture and storage of the product is required. A probiotic must have high numbers of viable organisms at the time of consumption to be effective, which impacts label claims and marketing of the final product.

There are five factors formulators should take into consideration when selecting a probiotic ingredient, according to Nigel Titford of BioGaia in Stockholm: survival in production, survival through GI tract, colonization, safety and efficacy in relevant target group. “All of this data needs to be related to the exact strain being selected, not on a species level,” he said. “If a combination of probiotics is being selected, the interactions between those cultures need to be considered and efficacy data using that combination should be considered.”

This sentiment was echoed by Udell, who added, “Probiotic strain selection is of utmost importance, as some health benefits may be strain-dependent.” Caroline Brons of DSM concurred, adding the probiotic strains selected should be backed by solid science, supporting the claims that are being made. “Not every strain is comparable, and science on one acidophilus strain may not be applicable to another,” she said. Gross also agreed, adding formulators should source clinically documented strains with proven benefit to the intended consumer of their finished product.

For a probiotic, the most important consideration is that the strain or strains are viable in the application in question. “Probiotic organisms are perishable when active, hence the refrigeration requirements for cultured dairy products, and are also subject to degradation over time even in an inactivate (freeze-dried) state in supplement form, particularly if not stored frozen,” said Tim Gamble, vice president of sales and marketing with Nutraceutix. “As a result, special care must be taken during manufacture, storage, shipment and distribution to protect probiotic products from exposure to air, heat and moisture.”

Heat, excessively low pH and other manufacturing factors can irreparably damage probiotic and prebiotic ingredients, said Terri Rexroat, global product manager, lactic cultures, for Cargill. In other cases, it may be possible to reformulate a product so the pH is slightly higher and therefore won’t damage the probiotic cells.

“The stability of the ingredient under processing conditions is also important when adding pre biotics in the formulations, ” Perera said. “Most common food processing practices involve high-pressure pumping, high heat treatments such as pasteurization, baking, and acid media. The chemical structure of the prebiotic ingredient should not degrade in the presence of such processing environment. Prebiotic ingredients should be easy to incorporate in the formula. Thus, functional properties such as dispersibility, solubility and flowability are also important. Most importantly, the prebiotic ingredient should have a good digestive tolerance not to cause flatulence or discomfort after consuming.”

Storage and manufacturing aren’t the only obstacles. There’s also the issue of gut transit. “For probiotics to be able to exert their health benefits, they must remain alive, not only during manufacturing and storage, but also in the GI tract, particularly in the stomach and the small intestine, where the conditions are harshest,” Brons said.

“Low pH and pepsin in the stomach, bile salts and pancreatic enzymes in the intestine can cause a significant reduction in viable cell count.” Some ingredient suppliers have developed patented technologies or applied enteric coating methodstoaid in gut delivery of probiotics. Nutraceutix, for example, patented its BIO-tract® gastric acid bypass technology and developed a new custom blended probiotic powder with acid resistance built-in, called Viablend™.

Mitsui & Co., representing Jintan, created a three-layer round seamless capsule for probiotics; Mitsui’s Tony Serra said, “The triple layer technology creates a very stable capsule versus moisture, heat, and enteric issues.”

Another critical consideration is ensuring the safety of the ingredient. Gamble suggested formulators “stick to non-GMO, naturally occurring probiotic organisms produced by an experienced, NSF certified, GMP facility.” Careful consideration should be given to the selection of strains and their suitability for certain applications. Non-standard strains, organisms that are not always considered true probiotics, or those that might be considered pathogens in GMP facilities, such as spore-forming organisms, soil-based organisms, yeasts, may be less than desirable.

Udell added: “From a safety point of view, the probiotic microorganisms should not be pathogenic strains or cause gastrointestinal distress. Although most strains of lactic acid probiotics have a good safety record, the safety of new prebiotics and probiotics, including genetically modified bacteria, must be confirmed.”

Finally, formulators should consider the relationship between pro- and prebiotics. “In terms of prebiotics, it’s best if one is chosen that is optimized for the probiotic being used; in other words, that they work symbiotically,” said Kathy Oneto, vice president of marketing for Attune Foods.

ORAFTI’s Van der Schraelen agreed: “By mixing probiotics with prebiotics positive results can be achieved. Some manufacturers are opting to develop these ‘synbiotic’ products—a concept based on findings that the survivability and viability of probiotics is enhanced when they are combined with prebiotics.”

Consumer Response— Or Lack Thereof?

“Consumer interest in probiotics, although still not where it should be, is rising dramatically as a result of increased advertising by national brands involved in both health supplement and dairy product marketing,” Gamble said. “More consumers are beginning to understand the many health benefits probiotics can convey. Unfortunately, consumer awareness of what makes a good and efficacious probiotic supplement, particularly in terms of production quality, shelf-life and effective intestinal delivery past stomach acids, still needs to increase.”

Consumers currently associate prebiotics and probiotics with yogurt and other dairy products. Since labeling and marketing are regulated by FDA, direct health claims for probiotic cultures cannot be advertised, creating a substantial restriction to the entire industry. Indirect claims on a yogurt package—such as “contains acidophilus and bifidobacteria, which are considered normal inhabitants of a healthy intestinal flora”—are a far cry from announcing the specific information about the strains listed on the package.

“Awareness of probiotic cultures seems to be somewhat limited, but interest is definitely growing in this category of functional ingredients,” Udell said. “There are still consumers who are uninformed about the beneficial health effects of pre- and probiotics, but as these ingredients become increasingly commercially available, along with the research being invested by numerous food companies, this will become a booming market.”

Perera agreed, adding health concerns drive most consumers to these products. “Consumers are highly interested in improving their diets by adding probiotics and prebiotics,” she said. “However, most consumers do not know different probiotic strains and prebiotic ingredients provide different health benefits.”

That said, Gross reported some comsumers are beginning to get the message on strain differentiation. “Today’s consumers are looking for products that have proven safety and efficacy—they want products utilizing documented strains for a specific health benefit,” she said.

Overall, many manufacturers are seeing a bright future for these ingredients. “Consumer interest is increasing rapidly,” Rexroat said. “Our customers are starting to better understand the health benefits, but we don’t believe the average consumer has much understanding at all yet. More specialized consumers that already focus on functional foods are probably ahead of the average consumer on this point.”

“Consumer interest in probiotics and prebiotics is definitely increasing,” Oneto concluded. “The sheer number of mainstream products and brands featuring the benefits of pro- and prebiotics is a perfect example of the growing appeal and understanding of this category. Consumers are becoming more comfortable with the idea of consuming foods, including ‘good’ bacteria, for a health benefit, and brands are doing a better job of making that message more consumer-friendly.” 

Tom Leveen is a Phoenix-based freelance writer and former associate editor with Natural Products INSIDER.