Some look to the success of probiotic-containing Activia yogurt as a sign of what the future may hold for food manufacturers. According to a January 2007 press release from The Dannon Company, Activia, promoted for its digestive health benefits, surpassed $100 million in U.S. retail grocery sales since the product’s January 2006 introduction—a feat achieved by less than 0.1% of all new product launches. In March 2007, Kraft Foods introduced cottage cheese under the Breakstone’s and Knudsen LiveActive brands. Their literature notes: “Contains prebiotic fiber that helps consumers meet their daily fiber goals and naturally regulate the digestive system.” The company has also launched Kraft LiveActive Cheddar Cheese with Probiotics in Canada, touting it as “The only cheddar cheese in Canada that contains two beneficial probiotic cultures (Bifidobacterium lactis and Lactobacillus rhamnosus).” A September 2007 U.S. introduction for the product is planned. Dean Foods Co. has introduced probiotic cottage cheese under the Dean Foods, Country Fresh and Land O’ Lakes brands with the claim “Improves Digestion.”
While dairy-based products and dietary supplements have been traditional probiotic strongholds, these microbes more often are found in other applications as well. For example, Mintel’s Global New Products Database (GNPD) shows that Flowers Foods recently launched Mrs. Freshley’s Snack Away Peanut Butter Wafers with the claim “Contains Probiotics” on the package front and Lactobacillus rhamnosus in the ingredient legend. Attune Foods Inc.’s Cool Mint Chocolate bar sports a “Probiotics good for life!” logo. Its website attests to each attune bar as containing “more than 10 billion probiotics,” and that the bars are formulated to “ensure each bar contains an effective number of probiotics when purchased.” The probiotics are a commercial mix of B. lactis, Lactobacillus acidophilus and Lactobacillus paracasei.
Indeed, the particular species (or better yet, strain or even phenotype and genotype) of the probiotic culture used may well be as important to the specific health benefits a culture provides as is the type of fatty acid in a nutritional lipid. L. bulgaricus, S. thermophilus and its own trademarked L. casei cultures grace the label of Dannon’s DanActive drink that is promoted for its immunity benefits. Stonyfield Farms, a pioneer in the probiotic U.S. market, incorporates “six live active cultures” on its yogurts. Three are the same strains found as in DanActive, but Stonyfield’s products additionally contain L. acidophilus, L. reuteri and bifidus. The starter cultures S. thermophilus and L. bulgaricus are required by the National Yogurt Association in order for a product to meet the definition of yogurt. They help provide the product’s typical texture and taste.
Cultivating the Best BacteriaWhich are the most optimal strains to use? Scientists are just starting to unravel the myriad factors that likely will result in the answer: “It depends.” For just one example, NutraIngredients.com reported on a study to appear in the June 2007 issue of Food Research International. The researchers investigated the ability of four probiotic strains, alone and in combination, to inhibit, displace and/or compete with seven pathogenic strains. Lead author Carmen Collado reported that all probiotic combinations “inhibited pathogenic infection by over 40% for some pathogens tested.” One conclusion was that a combination of different probiotic strains might reduce the ability of pathogenic bacteria to colonize the gut more effectively than one single strain.
The ability of probiotics to modulate the immune response is increasingly under investigation. For example, intestinal microflora also are said to play a crucial role in the inflammation associated with Crohn’s disease through their interaction with the mucosal immune system (Lindsay, JO, et al. 2006. Gut. 55:348-55). The U.K. researchers note that some bifidobacteria species are immunoregulatory, and that fructo-oligosaccharides (FOS) increase fecal and mucosal bifidobacteria. Their study assessed the effect of consuming 15g of FOS for three weeks on disease activity, bifidobacteria concentrations and mucosal dendritic cell function in 10 patients with moderately active Crohn’s disease. Results indicated that the FOS significantly increased fecal bifidobacteria levels and modified mucosal dendritic cell function, resulting in decreased Crohn’s disease activity.
While discovering the specific health attributes of probiotic strains is an area of hot research, factors impacting the viability of these cultures are also of great interest. Indeed, the ability for probiotic bacteria to survive processing (whether in a food or supplement), storage, then transit through the digestive system to reach and colonize the lower intestines in sufficient numbers, is key to many health benefits. Additionally, as with any organism, an optimal food source is crucial. This is where prebiotics play a role. These dietary fibers, indigestible by humans, ideally will preferentially support beneficial intestinal microflora. The following are just a few of the many recently published studies on prebiotic use in applications and in clinical research.
Survival StrategiesOne study (Aryana, KJ, et al. 2007. J Food Sci. 72:M79-M84) investigated various effects that inulins of three different chain lengths had on yogurt when added at 1.5% w/w to the yogurt mix. The yogurts’ characteristics were impacted in various ways. Yogurts with the shortest chain length inulin, which researcher Kayanush Aryana, assistant professor at Louisiana State University, says had an average polymerization degree of four, were judged to have better flavor. The longest chain inulin resulted in the least syneresis. However, regardless of the chain length of the inulin used, the yogurts all had comparable L. acidophilus levels, which were all higher than the control without inulin.
Another study (Saarela, M, et al. 2006. Int J Food Microbiol. 112:171-178) researched the ability of various fibers (10% and 20% b-glucan containing oat flours, apple fiber, wheat dextrin, polydextrose and inulin) to protect the viability of two L. rhamnosus strains during freeze-drying, storage in freeze-dried form and after formulation into apple juice and chocolate-coated breakfast cereals. Here, wheat dextrin and polydextrose were the most promising carriers in regards to both freeze-drying survival and storage stability at 37°C and when used in chocolate-coated breakfast cereals. The 20% b-glucan oat flour offered the greatest protection when the strains were incorporated into apple juice with a 3.5 pH. Freeze-dried cells were also more stable in chocolate-coated breakfast cereals when stored at 20°C as opposed to the apple juice. This study shows that the optimal carrier for a probiotic may depend, in part, in how it is eventually used.
Studies in regards to prebiotic influence on intestinal microflora are many and occasionally contradictory. For example, it has been noted that oligosaccharides found in human milk are important in developing the intestinal microflora of babies. These prebiotics are not in infant formulas, and thus bottle-fed children have an intestinal microflora significantly different than breastfed babies.
Researchers at Wyeth Nutrition conducted a study with prebiotics that gave somewhat equivocal results (Euler, AR, et al. 2005. J Pediatr Gastroenterol Nutr. 40:157-64). In their research, healthy infants two to six weeks of age were enrolled in a five-week study where they were given 1.5 or 3.0 g/L fructo-oligosaccharide-supplemented formula. Of the 72 infants completing the trial, 58 were formula fed and 14 were human milk fed. Mean counts of bifidobacteria and lactobacilli were similar in all groups at the beginning of the study, and no group experienced a significant change in counts. Formula-fed infants had higher counts of enterococci and bacteroides before FOS supplementation, and these counts did not change after supplementation. The researchers in this study concluded that it was safe to supplement infant formula with 1.5 or 3.0g/L of FOS, but that fortification had little effect on fecal flora and C. difficile toxin levels.
However, different results were obtained by a scientist at Numico Research who investigated the impact of formula fortified with oligosaccharides on infant intestinal microflora (Boehm, G, et al. 2005. Acta Paediatr Suppl. 94:18-21). He summarized research and clinical studies and concluded that a prebiotic mixture of 90% short-chain galacto-oligosaccharides and 10% long-chain fructo-oligosaccharides could stimulate the growth of bifidobacteria and lactobacilli. Fecal pH was decreased and pathogens levels were reduced to a level more similar to breastfed infants.
Clinical studies often use terminology and study designs similar to pharmaceuticals. One frequently referenced study assessed the tolerance and threshold doses of SC-FOS (short chain fructo-oligosaccharides) that would significantly increase fecal bifidobacteria levels. It also investigated the possibility of a dose-response relationship; that is, the higher the dose of prebiotic, the greater the effect (Bouhnik, Y, et al. 1999. The Journal of Nutrition. 129:113-116). Participants were randomly divided into groups and, while continuing with their usual diets, the 40 healthy adults also consumed two oral doses per day for seven days of a powder mixture containing 0, 2.5, 5, 10 and 20g SC-FOS. Bifidobacteria counts at the end of the week were significantly greater in the groups ingesting the 10g and 20g doses than in those who consumed zero and 2.5g. Although fecal pH did not differ among groups, there was a significant correlation between the amount of SC-FOS consumed and levels of fecal bifidobacteria. Excess flatulence was more frequent in subjects consuming 20g doses than in those consuming 5g or less. It was concluded that, based on this study, “10g/day is an optimal and well-tolerated dose of SC-FOS that significantly increased fecal bifidobacteria in healthy volunteers consuming their usual diet.”
A more recent study by the same lead researcher, Yoram Bouhnik, was conducted to determine the bifidogenic potential of different nondigestible carbohydrates (NDCHs) used in human diets (Bouhnik, Y, et al. 2004. Am J Clin Nutr. 80:1658–64). The carefully crafted study was titled, “The capacity of nondigestible carbohydrates to stimulate fecal bifidobacteria in healthy humans: a double-blind, randomized, placebo-controlled, parallel-group, dose-response relation study.” The 200 volunteers were divided into groups, and for each of seven days they consumed a placebo or one of the seven NDCHs. The SC-FOS, soybean oligosaccharides, galacto-oligosaccharides and type III resistant starch were all found to be bifidogenic. In a second phase, those NDCHs that had been bifodogenic in the first phase were given in doses of 2.5, 5.0, 7.5, 10g/day or a placebo in order to determine whether larger doses of the NDCHs had a greater effect. The effects of the seven-day treatment on bifidobacteria concentrations were found to differ significantly among the four NDCHs. However, for any given NDCH, no significant differences were found among doses, and there was no significant dose-time interaction. What was observed was that volunteers with low initial levels of bifidobacteria showed the greatest responses to consuming a prebiotic.
Another study supporting the concept that prebiotics can most significantly improve the bifidobacterial levels of those that most need it looked at the impact of a 5g or 8g daily dose of [long-chain] inulin (Kolida, S, et al. 2007. Eur J Clin Nutr. Epub ahead of print January 31). Populations of Bifidobacterium, Bacteroides-Prevotella, Lactobacillus-Enterococcus and Clostridium perfringens-histolyticum subgroup were monitored in the feces. This research found that bifidobacteria levels increased significantly with both inulin doses as compared to the placebo control. Although a “dose response effect” was not observed, as with the 2004 Bouhnik, Y, et al. study, the greater the initial levels of probiotics, the smaller the increase upon consuming the prebiotic doses.
The good news is both scientists and consumers have come a long way in understanding many of the benefits and issues surrounding pre- and probiotics. It is also good news—due to it being an intriguing area of research with great potential for human health—that both also have a ways to go to reach a better understanding of the issues.
www.NutraSolutions.comor www.PreparedFoods.com— Type “probiotics” or “prebiotics” into the search field on the home pages for more information on these topics
www.probioticscenter.com— For more information about probiotics
www.msnbc.msn.com/id/14903449— Consumer information site providing an overview of commercially available probiotic products
www.stonyfield.com/Wellness/SixLiveActiveCultures.cfm— Information on Stonyfield Farms probiotic choices, their benefits and relevant clinical research
www.fbfc.com/scoop/feb01/lacto.html— Lactic acid bacteria fermentation of foods
www.springerlink.com/content/v6766kk03621g577— Research investigating use of lactic acid cultures for
fermented corn bread
www.ajcn.org/cgi/reprint/80/6/1658.pdf— Research on characterizing lactic acid bacteria from sorghum
Yogurt Goes Nano-platinumSake, a beverage in which flecks of gold leaf have been incorporated, is a time-honored Japanese gift signifying wishes for good fortune. In September of 2006, Nippon Luna, the yogurt and fermented beverage subsidiary of Nippon Meat Packing Group, launched Platinum Yogurt, a product that builds upon that tradition. Due in part to its well-established supermarket and convenience store distribution channels, sales have been brisk and a sports-type, drinkable yogurt also has been introduced.
The product has a refreshing, not overly sweet taste and is intended for daily consumption. The package’s silver metallic color targets those with a fondness for trendy products. However, the uniqueness of the product is in its four micrograms of platinum colloid per container, an ingredient developed by Yusei Miyamoto, a Tokyo University professor.
Globally, many natural water products are sold on the basis of “miracle” curative properties. Scientists have investigated waters possessing the ability to scavenge free radicals. Electrolyzed reduced water (ERW), which uses active hydrogen as the scavenger, is one type. (Shirahata S, et al. 1997. Electrolyzed-reduced water scavenges active oxygen species and protects DNA from oxidative damage. Biochem Biophys Res Commun. 234:269-74. An abstract can be found on www.PubMed.gov.)
As part of wider research in this area, many studies have analyzed the trace minerals in water. ERW was found to contain small amounts of platinum nanocolloids as atomic hydrogen (active hydrogen) donors, enabling them to function as reactive oxygen species scavengers.
In his work, Miyamoto analyzed about 50 transition metals, some used as reduction catalysts in organic chemistry. He produced nanocolloids of dozens of metals and observed them in the presence of reactive oxygen species. Miyamoto’s platinum nanocolloids have a particle size of 3.3 nanometers (i.e., billionths of a meter) and are thought to be an unusually powerful antioxidant. Platinum Yogurt’s promotional phrase is roughly: “We will prevent you from getting rusty.”
Platinum nanocolloid is a recognized functional ingredient alongside more common items such as CoQ10. Although many experts caution about high intakes of these colloidal metals, the Japanese government permits their use as food additives. Nano-sized particle ingredients are being used in cosmetic products, especially in UV protectants and anti-aging skin creams. In addition, the health foods and supplements companies are beginning to include in them in tablets and new age beverages.—K. Kubomura
Kiyoko R. Kubomura, Ph.D., Kubomura Foods Advisory Consultants, is a lecturer at the World Health Organization (WHO) and adjunct professor at Tokai University of Medicine. She has consulted for companies such as Nestle, Pfizer and Dentsu and worked at Calpris Beverage Company and Aoyama Women’s Junior College.firstname.lastname@example.org