Supporting Beneficial Bacteria
Delivering probiotics and prebiotics to the intestinal tract is becomingeasier as companies develop new products and delivery systems

byHeather Granato

At any time, one persons digestive tract contains more than100 trillion bacteria with a total weight of around four pounds. This includesbetween 400 and 500 different types of bacteria, each with many strains, whichform the front line of immune defense and support nutrient absorption andgastrointestinal (GI) wellness. Bacteria found in the colon are especially instrumental inpreventing disorders by producing substances that raise or lower the risk ofdisease, immunity and malnutrition. Bacteria that produce lactic acid helpacidify the intestinal tract and protect the body from an overgrowth of harmfulbacteria. In addition, bacteria such as acidophilus and bifidus have been foundto increase the bioavailability of minerals and provide acid for the absorptionof calcium, copper, iron and magnesium.

This balanced intestinal flora is necessary for healthydigestion. Friendly flora manufacture a range of B complex vitamins, plusvitamins A and K. In a 1988 report, the U.S. surgeon general noted that a normalmicrobial flora could provide a passive mechanism for preventing infection.

To support beneficial intestinal flora, many consumers areturning to probiotics, microorganisms that combat pathogenic bacteria in thebody. The term is derived from the Greek meaning for life. The most wellknown beneficial bacteria are Lactobacilli such as Lactobacillus acidophilus (L.acidophilus) and Bifidobacteria such as Bifidobacterium bifidum (bifidus),though there are many strains used in supplements. These probiotic bacteriacolonize in the GI tract and help digest lactose, regulate peristalsis and bowelmovements, and digest protein to free amino acids.

L. acidophilus is perhaps the most researched probioticconcerning digestive health. There are several strains of L. acidophilus, eachwith different healing properties. The DDS strain, trademarked by Minnetonka,Minn.-based UAS Laboratories, has shown properties with significant benefits fordigestive health. It produces enzymes such as proteases that digest proteins andlipases, which in turn digest fat. The strain can also alleviate lactoseintolerance caused by the bodys deficiency of the lactase enzyme by producingsignificant quantities of lactase, which may help digest lactose and therebyreduce the possibility of bad breath, bloating, gas formation and stomachcramps. There also are reports that supplementation with acidophilusreduces E. coli infection in the intestine.

Along with these beneficial bacteria, many manufacturers aresupplying food for the microorganisms in the same dosage. These prebioticsinclude a range of non-digestible carbohydrates and sugars such as inulin andfructooligosaccharides (FOS). Prebiotics also help re-establish colonies ofbeneficial bacteria that already exist in the GI tract.

Delivering the Goods

With all their health benefits, probiotics are beingincorporated into many functional foods and beverages. However, expansion of themarket has been slow. Mary Ellen Sanders, Ph.D., owner of Centennial,Colo.-based Dairy & Food Culture Technologies, noted probiotics in theUnited States generally remain firmly in the dairy case on the food sideyogurt,fermented milks and cottage cheese are among the more popular items. Prebiotics,meanwhile, are not often found concurrently with those beneficial bacteria,being used more often in bakery applications.

There are many challenges in delivering these ingredients toconsumers. The four main areas Sanders suggested manufacturers address whenincorporating probiotics into a product are: maintaining probiotic viability in the final product; choosinga strain with substantiated benefits in humans; controlling cost whiledelivering efficacious levels of bacteria; and communicating the benefits of goodbacteria to wary consumers.

Strain selection is of increasing importance in the market,according to many suppliers. According to S.K. Dash, owner of UAS Laboratories,while lactic acid bacteria have a long history of safe use, there are newerstrains on the market that have no record of safe use in humans or animals. Agood indication of whether a strain is safe is whether it has GRAS (generallyrecognized as safe) status, he wrote in Health Benefits of Probiotics.For example, L. acidophilus species and some Bifidobacterium species areconsidered GRAS. Any new bacterial culture that has no history of prior safe usein humans should be subject to toxicological studies prior to incorporation inany probiotic supplement. It is important that the culture benefits, and doesntharm, the host.

This doesnt necessarily mean newer probiotics are not anoption. Many suppliers of probiotics are investing in long-term research toisolate different strains and investigate their safety and efficacy. Forexample, a five-year research project between the New Zealand Milk and HealthResearch Center, the New Zealand Dairy Institute and outside researchersresulted in isolating two strains (now supplied as the Howaru line fromArdsley, N.Y.-based Danisco). The company conducted extensive clinical andtoxicity studies on the HN019 and HN001 strains to support their use asfreeze-dried probiotics that can be used in both dairy and non-dairy products.

Another market trend is the increasing use of combinationformulas in supplements and foods. Combinations of up to 15 different strainsare found on the market, but this isnt necessarily a positive thing, saidMichael Shahani, director of operations with Nebraska Cultures, the WalnutCreek, Calif.-based makers of DDS-1. Theyre competing for the same space and food source, soyoull likely only get one or two major colonizations. Shahani said hiscompany recommends no more than five strains in any given product, and prefersonly two or three.

Maintaining viability in a product matrix is another issue.Probiotics are very sensitive to degradation by heat, light, moisture andoxygen. Even in the supplement arena, they are often shipped cold andrefrigerated in stores. Until more stable delivery systems are introduced intothe functional food/beverage arena, formulation options may be limited. Probioticscould work in a dry beverage mix application, which would overcome the moistureactivation concern, Shahani suggested. Refrigerated beverages with a short shelf life could alsodeliver viable organisms.

In an attempt to bridge the divide between ready-to-drink(RTD) beverages and probiotic shelf life, Vernon Hills, Ill.-based TetraPak andStockholm, Sweden-based BioGaia AB are now co-marketing the LifeTop Straw. Anindividually wrapped straw containing freeze-dried L. reuteri is attached to theside of a RTD beverage; when the drink is consumed through the straw, itdelivers the probiotics to the consumer in a liquid system. According to thecompany, the design overcomes the concern about shelf life of probiotics whilepermitting beverage companies to offer the health benefits of the bacteria.

Prebiotics, meanwhile, offer their own challenges informulation. In particular, concerns with prebiotics are proper dosing,associated GI discomfort with excessive intake, and functional properties,Sanders said. These products are both sweeteners and bulking agents, oftennecessitating reformation if a customer is adding them to an existing product,such as a beverage. When customers are looking to add the product at aneffective dosage level, the bulk can be an issue.

If a high dose is required to obtain significant benefits,the prebiotic may not be effective and will be more costly to include, said Linda Douglas, Ph.D., spokesperson for GTC Nutrition,based in Golden, Colo. The fiber content of many prebiotics can causediscomfort at high doses.

To overcome that concern, manufacturers may turn instead toshort-chain FOS. NutraFlora, GTCs offering, can be found in a host ofsupplements, as well as in functional food and beverage products. NutraFloraprovides all prebiotic benefits with the inclusion of exceptionally smallamounts, Douglas said. To enhance digestion, nutrient absorption(particularly increasing calcium absorption), and cholesterol metabolism, dosageranges from 1 g/d to 3 g/d. The short-chain structure also sets NutraFlora apartfrom some other fibersit does not participate in the Maillard browningreaction and retains high solubility and texture enhancement qualities.

If manufacturers can focus on taste, convenience, price andhealth benefits, probiotics combined with healthy foods are a great option,Sanders said. Its important to label the product in a truthful and notmisleading fashion, and to source ingredients from reputable companies.