Supporting Beneficial Bacteria
by Heather Granato
At any time, one persons digestive tract contains more than 100 trillion bacteria with a total weight of around four pounds. This includes between 400 and 500 different types of bacteria, each with many strains, which form the front line of immune defense and support nutrient absorption and gastrointestinal (GI) wellness. Bacteria found in the colon are especially instrumental in preventing disorders by producing substances that raise or lower the risk of disease, immunity and malnutrition. Bacteria that produce lactic acid help acidify the intestinal tract and protect the body from an overgrowth of harmful bacteria. In addition, bacteria such as acidophilus and bifidus have been found to increase the bioavailability of minerals and provide acid for the absorption of calcium, copper, iron and magnesium.
This balanced intestinal flora is necessary for healthy digestion. Friendly flora manufacture a range of B complex vitamins, plus vitamins A and K. In a 1988 report, the U.S. surgeon general noted that a normal microbial flora could provide a passive mechanism for preventing infection.
To support beneficial intestinal flora, many consumers are turning to probiotics, microorganisms that combat pathogenic bacteria in the body. The term is derived from the Greek meaning for life. The most well known 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 bacteria colonize in the GI tract and help digest lactose, regulate peristalsis and bowel movements, and digest protein to free amino acids.
L. acidophilus is perhaps the most researched probiotic concerning digestive health. There are several strains of L. acidophilus, each with different healing properties. The DDS strain, trademarked by Minnetonka, Minn.-based UAS Laboratories, has shown properties with significant benefits for digestive health. It produces enzymes such as proteases that digest proteins and lipases, which in turn digest fat. The strain can also alleviate lactose intolerance caused by the bodys deficiency of the lactase enzyme by producing significant quantities of lactase, which may help digest lactose and thereby reduce the possibility of bad breath, bloating, gas formation and stomach cramps. There also are reports that supplementation with acidophilus reduces E. coli infection in the intestine.
Along with these beneficial bacteria, many manufacturers are supplying food for the microorganisms in the same dosage. These prebiotics include a range of non-digestible carbohydrates and sugars such as inulin and fructooligosaccharides (FOS). Prebiotics also help re-establish colonies of beneficial bacteria that already exist in the GI tract.
Delivering the Goods
With all their health benefits, probiotics are being incorporated into many functional foods and beverages. However, expansion of the market has been slow. Mary Ellen Sanders, Ph.D., owner of Centennial, Colo.-based Dairy & Food Culture Technologies, noted probiotics in the United 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 to consumers. The four main areas Sanders suggested manufacturers address when incorporating probiotics into a product are: maintaining probiotic viability in the final product; choosing a strain with substantiated benefits in humans; controlling cost while delivering efficacious levels of bacteria; and communicating the benefits of good bacteria 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 newer strains on the market that have no record of safe use in humans or animals. A good indication of whether a strain is safe is whether it has GRAS (generally recognized as safe) status, he wrote in Health Benefits of Probiotics. For example, L. acidophilus species and some Bifidobacterium species are considered GRAS. Any new bacterial culture that has no history of prior safe use in humans should be subject to toxicological studies prior to incorporation in any probiotic supplement. It is important that the culture benefits, and doesnt harm, the host.
This doesnt necessarily mean newer probiotics are not an option. Many suppliers of probiotics are investing in long-term research to isolate different strains and investigate their safety and efficacy. For example, a five-year research project between the New Zealand Milk and Health Research Center, the New Zealand Dairy Institute and outside researchers resulted in isolating two strains (now supplied as the Howaru line from Ardsley, N.Y.-based Danisco). The company conducted extensive clinical and toxicity studies on the HN019 and HN001 strains to support their use as freeze-dried probiotics that can be used in both dairy and non-dairy products.
Another market trend is the increasing use of combination formulas in supplements and foods. Combinations of up to 15 different strains are found on the market, but this isnt necessarily a positive thing, said Michael Shahani, director of operations with Nebraska Cultures, the Walnut Creek, Calif.-based makers of DDS-1. Theyre competing for the same space and food source, so youll likely only get one or two major colonizations. Shahani said his company recommends no more than five strains in any given product, and prefers only two or three.
Maintaining viability in a product matrix is another issue. Probiotics are very sensitive to degradation by heat, light, moisture and oxygen. Even in the supplement arena, they are often shipped cold and refrigerated in stores. Until more stable delivery systems are introduced into the functional food/beverage arena, formulation options may be limited. Probiotics could work in a dry beverage mix application, which would overcome the moisture activation concern, Shahani suggested. Refrigerated beverages with a short shelf life could also deliver viable organisms.
In an attempt to bridge the divide between ready-to-drink (RTD) beverages and probiotic shelf life, Vernon Hills, Ill.-based TetraPak and Stockholm, Sweden-based BioGaia AB are now co-marketing the LifeTop Straw. An individually wrapped straw containing freeze-dried L. reuteri is attached to the side of a RTD beverage; when the drink is consumed through the straw, it delivers the probiotics to the consumer in a liquid system. According to the company, the design overcomes the concern about shelf life of probiotics while permitting beverage companies to offer the health benefits of the bacteria.
Prebiotics, meanwhile, offer their own challenges in formulation. 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, often necessitating reformation if a customer is adding them to an existing product, such as a beverage. When customers are looking to add the product at an effective 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 cause discomfort at high doses.
To overcome that concern, manufacturers may turn instead to short-chain FOS. NutraFlora, GTCs offering, can be found in a host of supplements, as well as in functional food and beverage products. NutraFlora provides all prebiotic benefits with the inclusion of exceptionally small amounts, Douglas said. To enhance digestion, nutrient absorption (particularly increasing calcium absorption), and cholesterol metabolism, dosage ranges from 1 g/d to 3 g/d. The short-chain structure also sets NutraFlora apart from some other fibersit does not participate in the Maillard browning reaction and retains high solubility and texture enhancement qualities.
If manufacturers can focus on taste, convenience, price and health benefits, probiotics combined with healthy foods are a great option, Sanders said. Its important to label the product in a truthful and not misleading fashion, and to source ingredients from reputable companies.