Prebiotics and Probiotics
Functional foods are generally described as foods that provide some health-benefits beyond traditional nutritional values. For example, probiotics and/or prebiotics may be added to foods to increase functionality.
The Greek translation of Probiotic is "for life." A probiotic is a microorganism in a food or supplement containing live microorganisms that are present in sufficient numbers to actively enhance consumers' health by improving the balance of microflora or microorganisms in the gastrointestinal tract. Today probiotic bacteria such as Lactobacillus and Bifidobacterium are added to fermented foods and other foodstuffs (Aubertin, 2001).
Yogurt is the most familiar product containing beneficial microorganisms. There are, however, other foods that may contain added probiotics, such as sour cream, fruit juices and buttermilk. Fermented foods, such as cheese and sauerkraut, which contain beneficial bacteria, have been a part of the human diet for centuries. Probiotics are also available in tablet, spray, capsule, or powder forms.
Probiotics must be able to survive the aerobic condition of the product in which they are contained, as well as the acidic condition of the stomach. They must also be able to survive the bile levels and pancreatic secretions into the small intestine. (Shah, 2001)
Probiotics may have a number of benefits. Certain probiotics have lactase activity, which is needed to properly digest lactose or milk sugar. For example, people that are lactose-intolerant may be able to eat yogurt that contains organisms that produce lactase enzymes. (Guo, 2001)
Probiotics may also help keep the intestinal tract more acidic, making it difficult for disease causing organisms or pathogens to persist. Scientists agree that bacteria compete for nutrients in the intestinal tract so if probiotics are present in abundance the more virulent organisms may be crowded out.
The immune system may also be stimulated by probiotics. Studies in children suggest that probiotics can help repress infections and allergic responses. (Guo, 2001)
Probiotics may reduce antibiotic-associated infections and diarrhea. Diarrhea is a common side effect of antibiotic treatment. Antibiotics can destroy both good and bad microorganisms in the intestinal tract. A number of probiotics show promise in alleviating antibiotic related diarrhea.
Other health benefits of probiotics, which have been documented or indicated, include suppressing colon cancer, preventing vaginitis, reducing serum cholesterol, improving bowel regularity and maintaining remission in inflammatory bowel disease.
Prebiotics are nondigestible or partially digestible food ingredients that beneficially affect the host (consumer) by selectively stimulating the growth and/or activity of one or more of a limited number of bacteria in the colon, and thus improve host health. (Gibson & Roberfroid, 1995; Schrezenmeir & Vrese, 2001; Gibson et al., 2004) Individual prebiotics may stimulate the growth and/or activity of some indigenous probiotics but not others.
Prebiotics are not digested by human enzymes and therefore have a low caloric value and are efficiently used in low calorie (energy) foods. Because of their non-digestibility prebiotics show fiber-like properties, mainly stool bulking. In this perspective prebiotics are efficiently used to increase stool frequency and to treat constipation. (Kleessen et al., 1997; Den Hond et al., 2000)
The benefits of probiotics are dependent on their viability, growth, and metabolic activity, which can be maximized by prebiotics. Products containing both probiotics and prebiotics are called synbiotics. In certain synbiotic applications, with careful selection of the appropriate strain in combination with the right prebiotic, the functionality of the probiotic can be enhanced by the prebiotic. Other synbiotic applications aim to combine the functionally of both the pre- and probiotic compound or even achieve synergistic effects of combining both. Food ingredient suppliers are now making it easier to add probiotics and prebiotics to foods and beverages by offering blends of synbiotics with the right proportion of pro- and prebiotics to obtain the desired beneficial health effects, as well as improved survival of the live strain.
Selected Examples of Prebiotics
A number of food ingredients have been shown to be prebiotics. These include lactulose, lactitol oligofructose (and sc-FOS), inulin and galacto-oligosaccharides (GOS), tagatose, isomaltooligosaccharides, polydextrose, and digestive resistant maltodextrin. (Gibson et al., 2004)
Inulin and oligofructose are well-documented prebiotics. They selectively stimulate bifidobacteria and lactobacilli in the gut at the expense of pathogenic bacteria such as clostridia and coliforms. In total, 9 interventional human studies, some of them with more than one type of treatment, have been performed and published on inulin and/or oligofructose from chicory as the only active ingredient, to demonstrate their prebiotic effect. more...
The effect of lactitol on the intestinal flora has been extensively studied both in vitro and in vivo. In vitro studies show that lactitol stimulates the growth of Lactobacillus spp. and Bifidobacterium. The growth of proteolytic bacteria such as Enterobacterium and Enterococcus is inhibited. (Yuki et al., 1999; Kontula et al., 1999; Kitler et al., 1992; Felix et al., 1990). more...
- Tagatose alters the composition and population of colonic microflora. Both changes in microbial population density and species were observed. Pathogenic bacteria were reduced and specific beneficial bacteria (e.g., lactobacilli) were increased. Tagatose is highly butygenic; about 50% of the short chain fatty acids (SCFA) produced are butyrate.
Clinical studies have shown that polydextrose increases the proportion of Bifidobacterium in the colonic microflora. The shift towards saccharolytic fermentation is also evidenced by reduced colonic pH, increased butyrate production and a reduction in branched short chain fatty acids. more...
Digestive resistant maltodextrin (DRM) has been shown to increase fecal concentrations of beneficial bacteria, including bifidobacteria, in dogs. (Flicklinger et al., 2000). In vitro studies of cecal contents of rats show that short-chain fatty acids are generated in the presence of DRM and further studies on rats show that DRM to prevent intestinal mucosal atrophy occurring due to the long term administration of enteral nutrition (Ohkuma & Wakabayashi, 2001).
Labeling Products Containing Probiotics or Prebiotics
Fifty-three percent of Americans say they want more information on "active cultures," but only 9 percent are familiar with the term probiotics. Nonetheless, the probiotic market is the world's largest segment of the functional foods and beverages market. (Sloan, 2004) Products include dairy drinks and desserts, yogurts, bakery mixes, cakes and bread, table spreads and other products containing "gut-healthy" bacteria. Prebiotics like inulin and oligofructose are used in a large variety of products to support and increase the indigenous (naturally occurring) bifidobacteria and to support added microorganisms (probiotics).
Balance is a common theme on products containing pre- and probiotics. Phrases such as stimulates digestion, boosts immune system, restores intestinal flora, strengthens bodies natural defense, for well balanced microflora, reduces bad bacteria and maintains a healthy digestive system are found on such products. Some products actually name the probiotic in the product, such a Bifidobacteria, lactic acid bacteria and bilact cultures – or state "with probiotics" respectively "with prebiotics" or "prebiotic".
Examples of probiotic products currently available and labeled accordingly include:
Sweden-based Skane Dairy's ProViva fruit drink labeled "ProViva reduces the build-up of gas in the stomach." (This product was awarded Europe's first health claim for a probiotic product.)
Group Danone is marketing in the U.S. DanActive "daily dose" drinks sold in 100 ml. mini-bottles, labeled "DanActive. Immunity. Helps Naturally Strengthen Your Body's Defense System." The product also claims to help "maintain the balance of your intestinal flora." (Sloan, 2004)
On the prebiotic product side is Litesse®. The sugar-free polydextrose has a low glycemic load and is suitable for products aimed at diabetics and the health and wellness market.
The Institute of Food Technologists assembled an Expert Panel on Functional Foods. The Panel identified a number of areas requiring change to further encourage the development of functional foods. (Clydesdale, 2004) Examples of recommendations considered critical are:
- Modify the current definition and application of the term "nutritive value."
- Allow product labeling and health claims to accurately reflect the scientific data without triggering drug status.
- Develop incentives for companies to invest in functional foods research and development.
Abrams S., Griffin I., Hawthorne K., Liang L., Gunn S., Darlington G., Ellis K. 2005.“A combination of prebiotic short- and long-chain inulin-type fructans enhances calcium absorption and bone mineralization in young adolescents.“ Am J Clin Nut, 82:471-476
Anon. 2005. 27th Session of Chemical Codex on Nutrition and Foods for Special Dietary Uses Bonn, Germany 21-25 Nov 2005 Document CL 2005/53 - FSDU Dec 2005
Aubertin A. 2001. “Not all bacteria are bad: Probiotics promise help to G.I. tract, immunity.” Environmental Nutrition, 24(11):1,6.
Ballongue, J., Schumann, C., Quignon, P. 1997. “Effects of lactulose and lactitol on colonic micro flora and enzymatic activity Scandinavian.” Journal of Gastroenterology, 32 (s222):41-44.
Bertelsen H., Andersen H., Tvede M. 2001. “Fermentation of D-tagatose by human intestinal bacteria and dairy lactic acid bacteria.” Microbial Ecology in Health and Disease, 13:87-95.
Blanc, P., Daures, J.P., Rouillon, J.M., Peray, P, Pierrugues, R., Larrey, D., Gremy, F., Michel, H. 1992. “Lactitol or lactulose in the treatment of chronic hepatic encephalopathy: results of a meta-analysis.” Hepatology (Baltimore), 15: 222-228.
Boehm G., Lidestri M., Casetta P., Jelinek J., Negretti F., Stahl B., Marini A. 2002. "Supplementation of a bovine milk formula with an oligosaccharide mixture increases counts of fecal bifidobacteria in preterm infants.” Arch Dis Child Fetal Neonatal Ed 86; F178-F181L.
Bomba A., Nemčová R., Gancarčíková S., Herich R., Guba P., Mudroňová D. 2002. “Improvement of the probiotic effect of micro-organisms by their combination with maltodextrins, fructo-oligosaccharides and polyunstaturated fatty acids.” BJN, 88 Suppl. 1: S95 – S99.
Bosscher D., Van Loo J., Franck A. 2005. “The role of inulin and oligofructose in the management of inflammatory bowel diseases.” Int. Nutrition Conference September 2005, South-Africa.
Bouhnik Y., Raksine L., Simeneau G., Vicaut E., Neut C., Flourié B, Brouns F., Bornet F. 2004. “The capacity of nondigestible carbohydrates to stimulate fecal bifidobacteria in healthy humans: a double-blind, randomized; placebo-controlled, parallel-group; dose-response relation study.” Am. J. Clin. Nutr, 80: 1658 – 1664.
Buddington K., Donahoo J., Buddington R., 2002. “Dietary oligofructose and Inulin Protect Mice from Enteric and Systemic Pathogens and Tumor Inducers.” J. Nutr., 132, pp. 472-477.
Cani P., Dewever C., Delzenne N.; 2004. “Inulin-type fructans modulate gastrointestinal peptides involved in appetite regulation (glucagons-like peptide-1 and ghrelin) in rats.” BJN: 92: 521-526.
Cani P., Joly E., Delzenne N. 2005. “Oligofructose promotes satiety in Healthy human: a pilot study.” In press.
Clydesdale F. 2004. “Functional Foods: Opportunities & Challenges.” Food Technology 58(12):35-40.
Cummings J., Christie S., Cole T. 2001. “A study of fructo oligosaccharides in the prevention of travelers’ diarrhea.” Aliment. Pharmacol. Ther., 15, pp. 1139-1145.
Den Hond E., Geypens B., Ghoos Y. 2000. “Effect of high performance chicory inulin on constipation.” Nutrition Research, 20, pp. 731-736.
Daubioul C., Rousseau N., Demeure R., Gallez B., Taper H., Declerck B, Delzenne N. 2002. “Dietary fructans, but not cellulose, decrease triglyceride accumulation in the liver of obese zucker fa/fa rats.” J. Nutr. 967 – 973.
Endo K., Kumemura M., Nakamura K., Fujisawa T., Suzuki K., BennoY., Mitsuoka T. 1991. “Effect of high cholesterol diet and polydextrose supplementation on the microflora, bacterial enzyme activity, putrefactive products, volatile fatty acids (VFA), and pH of the feces in health volunteers.” Bifidobacteria Microflora 10:53-64.
Felix, Y.F., Hudson, M.J., Owen, R.W., et al. 1990. “Effect of dietary lactitol on the composition and the metabolic activity of the intestinal micro flora in the pig and in humans.” Microbial Ecology in Health and Disease, 3: 259-267.
Femia A., Luceri C., Dolara P., Giannini A., Biggeri A., Salvadori M., Clune Y., Collins K., Paglierani M., Caderni G. 2002. “Antitumorigenic activity of the prebiotic inulin enriched with oligofructose in combination with the probiotics Lactobacillus rhamnosus and Bifidobacterium lactis on azoxymethane-induced colon carcinogenesis in rats.” Carcinogenesis, Vol. 23, No. 11, pp. 1953-1960.
Fiordaliso M., Kok N., Desager J.P., Goethals F., Deboyser D., Roberfroid M., Delzenne N. 1995. “Dietary oligofructose lowers triglycerides, phospholipids and cholesterol in serum and very low density lipoproteins in rats.” Lipids, 30:163 – 167.
Flicklinger E.A., Wolf B.W., Garleb K.A., Chow J., Leyer G.J., Johns P.W., Fahey G.C. 2000. “Glucose-based oligosaccharides exhibit different in vitro fermentation patterns and affect in vivo apparent nutrient digestibility and microbial population in dogs.” Journal of Nutrition 130(5):1267-1273.
Flood, MT, Auerbach, MH and Craig, SAS. 2004. A review of the clinical toleration studies of polydextrose in food. Food and Chemical Toxicology 42, 1531-1542
Furrie, E. Macfarlane, S. Kennedy, A. Cummings, J.H. Walsh, S.V. O'Neil, D.A. Macfarlane, G.T. 2005. Synbiotic therapy (Bifidobacterium longum/Synergy 1) initiates resolution of inflammation in patients with active ulcerative colitis: a randomised controlled pilot trial. Gut, 54:242-249.
Gibson G. Roberfroid M.B. 1995, “Dietary modulation of the human colonic microbiota: Introducing the concept of prebiotics.” Journal of Nutrition 125:1401-1412.
Gibson G. Wang X.. 1994. “Bifidogenic properties of different types of fructo-oligosaccharides.” Food Microbiology, 11:491 – 498.
Gibson G., Beatty E., Wang X., Cummings J. 1995. “Selective Stimulation of Bifidobacteria in the Human Colon by Oligofructose and Inulin.” Gastroenterology, 108, pp. 975-982.
Gibson G.R,. Probert H.M., Van Loo J., Rastall R.A., Roberfroid M.B. 2004. “Dietary modulation of the colonic microbiota: updating the concept of prebiotics.” Nutrition Research Reviews, 17, pp. 259-275.
Griffin I., Davila P., Abrams S. 2002. “Non-digestible oligosaccharides and calcium absorption in girls with adequate calcium intakes.” BJN; 87:S187-S191.
Griffin I., Hicks P., Heaney R., Abrams S. 2003. “Enriched chicory inulin increases calcium absorption mainly in girls with lower calcium absorption.” Nutrition Research, 23:901-909.
Guo, P. 2001. “The essential microflora for total well being.” Dietitian’s Edge 40-7.
Hara, H; Suzuki, T and Aoyama, Y. 2000. Ingestion of the soluble dietary fibre, polydextrose, increases calcium absorption and bone mineralization in normal and total-gastrectomized rats. B J Nutr, 84, 655-661
Ishizuka, S; Nagai, T and Hara, H. 2003. Reduction of aberrant crypt foci by ingestion of polydextrose in the rat colorectum. Nutrition Research 23, 117-122
Jackson K., Taylor G., Closhessy A., Williams C. 1999. “The effect of daily intake of inulin on fasting lipid, insulin and glucose concentrations in middle-aged men and women.” BJN, 82:23 -30.
Kitler, M.E., Luginbühl, M., Lang, O., Wuhl, F., Wyss, a., Lebek, L. 1992. “Lactitol and lactulose. An in vivo and in vitro comparison of their effects on the human intestinal flora.” Drug Invest., 4(1):73-82.
Kleessen B., Sykura B., Zunft H., Blaut M. 1997. “Effects of inulin and lactose on fecal microflora, microbial activity, and bowel habit in elderly constipated persons.” Am. J. Clin. Nutr., 65:1397-1402.
Klinder A., Förster A., Caderni G., Femia A.P., Pool-Zobel B.L. 2004a. “Fecal water genotoxicity is predictive of tumor-preventive activities by inulin-like oligofructoses, probiotics (Lactobacillus rhamnosus and Bifidobacterium lactis), and their synbiotic combination.” Nutrition and Cancer, 49(2):144 – 155.
Klinder A., Gietl E., Hughes R., Jonkers N., Karlsson P., McGlyn H., Pistoli S., Tuohy K., Rafter J., Rowland I.R., Van Loo J., Pool-Zobel B.L. 2004b. “Gut fermentation products of inulin-derived prebiotics beneficially modulate markers of tumour progression in human colon tumour cells.” Int. J. Cancer Prevention, 1:19-32.
Knol J., Scholtens P., Kafka C., Steenbakkers J., Gross S., Helm K., Klarczyk M., Schöpfer H., Böckler H-M., Wells J. 2005. “Colon microflora in infants fed formula with galacto- and fructo-oligosaccharides: more like breast-fed infants.” Journal of Paediatric Gastroenterology and Nutrition, 40:36-42
Kontula, P., Suihko, M.L., Von Wright, A., and T. Mattila-Sandholm, T. 1999. “The effect of lactose derivatives on intestinal lactic acid bacteria.” Journal of Dairy Science, 82:249-256.
Langlands S., Hopkins M., Coleman N., Cummings J. 2004. “Prebiotic carbohydrates modify the mucosa associated microflora of the human large bowel.” Gut, 53:1610-1616.
Lebek G., Luginbühl M. 1989. “Effects of lactitol and lactulose on human intestinal flora.” In: H.O. Conn, J. Bircher, eds. Hepatic Encephalopathy: Management with lactulose and related carbohydrates. Medi-Ed Press, Michigan: 271-314.
Letexier D., Diraison F., Beylot M. 2003. “Addition of inulin to a moderately high-carbohydrate diet reduces hepatic lipogenesis and plasma triacylglycerol concentrations in humans.” Am. J. Clin. Nutr., 77:559-564.
Lewis S. Burmeister S. Brazier J. 2005. Effect of the Prebiotic Oligofructose on Relapse of Clostridium difficile-Associated diarrhea: A Randomized, Controlled Study.” Clinical Gastroenterology and Hepatology. 3:442-448.
Lindsay J.O., Whelan K., Stagg A.J., Gobin P., Omar Al-Hassi H., Rayment N., Kamm M.A., Knight S.C., Forbes A. 2005. “The clinical, microbial and immunological effects of fructo-oligosaccharides in patients with Crohn’s disease.” Gut online, September 2005.
Mäkivuokko, H, Nurmi, J, Nurminen, P, Stowell, J and Rautonen, N. 2005. In Vitro Effects on Polydextrose by Colonic Bacteria and Caco-2 Cell Cyclooxygenase Gene Expression. Nutrition and Cancer 52(1), 94-104
Menne E., Guggenbuhl N., Roberfroid M. 2000. “Fn-type Chicory Inulin Hydrolysate Has a Prebiotic Effect in Humans.” J. Nutr., 130:1197-1199.
Moro G., Minoli I.,, Mosca M., Fanaro S., Jelinek J., Stahl B., Boehm G. 2002. "Dosage-Related Bifidogenic Effects of Galacto- and Fructooligosaccharides in Formula-Fed Term Infants.” J. Pediatric Gastroenterology and Nutrition, 34:291-295.
Ohkuma K., Wakabayashi S. Fibersol-2: a Soluble, Non-digestible, Starch-derived Dietary Fibre in Advanced Dietary Fibre Technology, B.V. McCleary & L. Prosky (eds), Blackwell Science, Oxford, UK, 2001, pp 509-523.
Patent JP 11-113484; 1999; “Method of improvement of survival of Bifidus bacteria.”
Peuranen, S; Tiihonen, K; Apajalahti, J; Kettunen, A; Saarinen, M and Rautonen, N (2004) Combination of polydextrose and lactitol affects microbial ecosystem and immune responses in rat gastrointestinal tract. B J Nutr 91, 905-914
Probert, HM; Apajalahti, JHA; Rautonen, N; Stowell, J and Gibson, G. 2004. Polydextrose, Lactitol and Fructo-Oligosaccharide Fermentation by Colonic Bacteria in a Three-Stage Continuous Culture System. Applied & Env Micro 70, No 8, 4505-4511
Rao V., 2001. “The prebiotic properties of oligofructose at low intake levels.” Nutrition Research, 21, pp. 843-848.
Ravelli, G.P., Whyte, A., Spencer, R., Hotten, P., Harbron, C., Keenan, R. 1995. “Effect of lactitol intake upon stool parameters and the faecal bacterial flora in chronically constipated women.” ActaChemo, 2: 243-255.
Roberfroid M.B., Van Loo J., Gibson G.R. 1998. “The bifidogenic nature of chicory inulin and its hydrolysis products.” J. Nutr., 128:11 -19.
Roller M., Rechkemmer G., Watzl B. 2004a. “Prebiotic inulin enriched with oligofructose in combination with the probiotics Lactobacillus rhamnosus and Bifidobacterium lactis modulates intestinal immune functions in rats.” J. Nutr., 134: 153 – 156.
Roller M., Femia A.P., Caderni G., Rechkemmer G., Watzl B. 2004b. “Intestinal immunity of rats with colon cancer is modulated by oligofructose-enriched inulin combined with Lactobacillus rhamnosus and Bifidobacterium lactis.” BJN, 92:931-938.
Scevola, D., Bottari, G., Franchini, A., Guanziroli, A., Faggi, A., Monzillo, V., Pervesi L., Oberto, L.1993b. “The role of Lactitol in the regulation of the intestinal micro flora in liver disease.” Giornale di Malattie Infettive e Parassitarie, 45(7-8):906-918.
Scevola, D., Bottari, G., Oberto, L., Monzillo, V., Pervesi L., Marone, P. 1993a. “Intestinal bacterial toxins and alcohol liver damage: effect of lactitol, a synthetic disaccharide.” La Clinica Dietologica, 20:297-314.
Schmelzle H., Wirth S., Skopnik H., Radke M., Knol J., Böckler H.M., Brönstrup A., Wells J., Fusch C. 2003. “Randomized double-blind study of the nutritional efficacy and bifidogenicity of a new infant formula containing partially hydrolyzed protein, a high b-palmitic acid level, and nondigestible oligosaccharides.” Journal of Pediatric Gastroenterology and Nutrition, 36:343 – 351.
Schrezenmeir J., de Vrese M. 2001. “Probiotics, prebiotics, and synbiotics—approaching a definition.” American Journal of Clinical Nutrition 73(supple):361S-4S.
Shah NP. 2001. “Functional foods from probiotics and prebiotics.” Food Technology 55(11):46-53.
Sloan AE. 2004. “Top 10 Functional Food Trends 2004”; Food Technology 58(4):28-51.
Taper H., Delzenne N., Roberfroid M. 1997. “Growth inhibition of transplantable mouse tumors by non digestible carbohydrates.” Int. J. Cancer, 71:1109-1112
Taper H., Lemort C., Roberfroid M. 1998. “Inhibition effect of Dietary inulin and oligofructose on the growth of transplantable mouse tumor.” Anticancer Research, 18: 4123-4126.
Taper H., Roberfroid M. 1999. “Influence of inulin and oligofructose on breast cancer and tumor growth.” J. Nutr., 129:1488S – 1491S.
Tiihonen, K; Suomalainen, T; Tynkkynen, S and Rautonen, N : Effect of a probiotic bacteria mixture with polydextrose or galacto-oligosaccharide supplementation on intestinal microbiota and immune responses. Comparison between a rat model and clinical trials. In press.
Tuohy K., Kolida S., Lustenberger A.M., Gibson G. 2001a. “The prebiotic effects of biscuits containing partially hydrolysed guar gum and fructo-oligosaccharides – a human volunteer study.” BJN, 86:341-348.
Touhy K., Finlay R., Wynne A., Gibson G. 2001b. “A Human Volunteer Study on the Prebiotic Effects of HP-Inulin – Faecal Bacteria Enumerated Using Fluorescent In Situ Hybridisation (FISH).” Anaerobe, 7:113-118.
van den Heuvel E., Muys T., van Dokkum W., Schaafsma G. 1999. “Oligofructose stimulates calcium absorption in adolescents.” Am. J. Clin. Nutr., 69:544-548.
Van Loo J. 2004. “The specificity of the interaction with intestinal bacterial fermentation by prebiotics determines their physiological efficacy.” Nutrition Research Reviews, 17: 89 – 98.
Van Loo J., Bosscher D., Caderni G., Collins J.K., Pool-Zobel B., Rowland I., Watzl J. 2005. “Consumption of chicory fructans and probiotics reduces cancer risk biomarkers in colon cancer and polypectomized human subjects.” Poster, AARC Frontiers in cancer prevention, Chicago.
Waligora A.J., Campeotto F., Nicolis I., Bonet A., Dupont C., Butel, AJ. “Effects of oligofructose supplementation in infants 6 to 24 months of age on gut microflora and well-being: a double-blind, placebo-controlled, randomized trial. Submitted for publication.
Wang X., Gibson G.; 1993; “Effects of the in vitro fermentation of oligofructose and inulin by bacteria growing in the human large intestine.” Journal of Applied Bacteriology, 75:373-380.
Yuki, N., Watanabe, K., Mike, A., Tagami, Y., Tanaka, R., Ohwaki, M., Morotomi, M. 1999. “Survival of a probiotic, Lactobacillus casei strain Shirota, in the gastrointestinal tract: Selective isolation from faeces and identification using monoclonal antibodies.” International Journal of Food Microbiology, 48:51-57.
Zhong J., Luo B., Xiang M., Lui H., Zhai Z., Wang T., Craig SAS. 2002. “Studies on the effects of polydextrose on physiological function in Chinese people.” American Journal of Clinical Nutrition 72:1503-9