Hippocrates´ sayings from 4th century BC “death sits in the bowels” and “bad digestion is the root of all evil” are well known.[1]  Probiotics have revealed evidence of efficacy in more than 1000 RCTs from January 2000 till December 2012, viagra sale in relation to human health improvements in many ways.


Probiotics are living microorganisms, which are beneficial for the host. FAO/WHO define probiotics as “Live microorganisms which when administered in adequate amounts confer a health benefit on the host”.[2]   These microorganisms are instrumental for the intestinal microbial population by augmentation.  Lactobacillus and Bifidobacterium are most widely used commercially and have been studied the most.[3], [4]


Prebiotics are a food ingredient that is beneficial for the host’s digestive system and health by stimulating selectively the growth of some bacteria’s in the colon.  Prebiotics are non-digestible and can stimulate the activity of the bacteria in the colon e.g. fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), lactulose and inulin (sugar substitutes).  Known prebotics are i.e. peptides, proteins, lipids and non-digestable oligosaccharides (NDOs).[7]

Clear criteria are needed to classifying food ingredients as a prebiotic.  According to Roberfroid[8] these criteria are:  “ 1) resistance to gastric acidity, to hydrolysis by mammalian enzymes, and to gastrointestinal absorption; 2) fermentation by intestinal microflora; and  3) selective stimulation of the growth and/or activity of those intestinal bacteria that contribute to health and well-being.”


Prebiotics, in some cases, might be beneficial for the probiotic (bifidobacteria especially) and that is “a synbiotic concept”.  According to Andersson et al[9] synbiotics are defined as “mixtures of probiotics and prebiotics that beneficially affect the host by improving the survival and implantation of live microbial dietary supplements in the gastrointestinal tract of the host”.  Examples are FOS and Bifidobacterium and Lactitol and Lactobacillus together.  Fermented milk products are good example.

THE COMPOSITION of the Human Gut Microbiota

Anaerobic bacteria (belonging to few of known bacterial phyla) are dominating in the adult’s human gut.  Major phyla in a “normal” human gut are; Firmicutes (Gram-positive; low G+C; classes Bacilli /Clostridia) and Bacteriodetes (Gram-negative; genera Bacteroides / Prevotella / Alistipes).  Proteobacteria (Gram-negative; genera Escherichia /Salmonella / Vibrio / Helicobacter), Verrumicrobia, Anctinobacteria (Gram-positve; high G+C; genus Bifidobacterium), Fusobacteria and Cyanobacteria are other species of the phyla Proteobacteria, which are also present in the gut.[10],[11],[12]  Bacteroidetes and Firmicutes dominate the distal gut microbiota.  They constitute over ninety percent of the known phylogentetic categories.[13]  From the proximal to the distal gut, the microbial density increases along with increasing bacterial diversity[14] and 300-500 different bacterial species are present only in the large intestines.  There is marked diversity of the gut microbiome amongst healthy individuals, especially with infants, but with time the gut microbiome does converge to more similar phyla.[15],

THE ROLE of the Microbiota in the Gut

The microbes in our body, especially in the gut, play very important part in relation to nutrition and on human physiology.  Microbes are very important for human life and all changes may influence the health of the host.  Bowel diseases and obesity has been associated with changes of the gut microbiome.[16],[17],[18],[19],[20]  Beneficial homeostasis between the host and the microbiota must be ensured by restricted microbial growth in the intestines, where the mucosal immune system operates and tight regulation of the gut microbiota prevents chronic inflammation in the host.[21]  Several aspects of the immune tissues in the host are developed and directed by the intestinal micro-biota, as well as immune cell populations and immune mediators.  According to Baugher et al6 probiotics are important for in the gastrointestinal tract.  Probiotics help to suppress allergic asthma, decrease flue-like symptoms in children, lower serum cholesterol levels and protects against infection.[22],[23],[24],[25]

IMPACTING Factors on the Microbiota Composition

Dysbiosis or dysbacteriosis is a microbial imbalance in the gut and first coined by Metchnikoff.[26]  When the microbiota produces harmful effects through quantitative as well as qualitative changes in the gut flora alongside changes in their metabolic activities and in their local distribution, it can be referred as a state of dysbiosis.[27]  The gut microbial ecosystem is modulated by the diet.[28]  Hydrogen sulfate inhibits oxidation of butyric acid leading to interrupted mucous and lipid synthesis for the coloncyte membranes and incomplete absorption of ions.[29],[30]  Dietary changes can harm the beneficial flora[31] in the gut as well as stress[32],[33],[34],[35],[36],[37] (psychological and physical), radiation, chronic inflammation and metabolic dysfunction, hygiene, hyper-immunity (IL-6, IL-12, TNF) and altered GIT.[38]  The most common cause and the most significant one is the use of antibiotics.  The influence depends on the spectrum of activity, length of administration, dosage and pharmacokinetics.  When an antimicrobial agent is active against both gram-negative and gram-positive organisms, there will be greater impact on the gut flora.[39],[40]   Altered intestinal flora can lead to several diseases e.g. asthma, obesity, cardiovascular diseases, arthritis and inflammatory bowel diseases.

PROBIOTIC Products and Major Marketing Issues in the EU

In December 2006 the Council and Parliament approved the Regulation on nutrition and health claims, which lays the rules across the EU.[41]  Regarding probiotics, specific health claims on foods are allowed, if sufficient evidence is available.[42],[43]

PROBIOTIC Products and Major Consumption Issues in the EU

In Europe, the probiotic dairy products e.g. yogurts and milks account for 65% of the functional foods market. Products need to be made to fit the consumer’s health-beliefs and lifestyle and the target for marketing must be appropriate.  Consumer researches have reviled that, predominately females, well-educated and high earners aged 35-55 years as well as being focused on their health, are typical functional-food-consumers.  Future opportunities could lie in natural alternatives like probiotics to inhibit pathogens, as increasing resistance to antibiotics is becoming a major public health problem.[44]


Probiotics, prebiotics and synbiotics are all important for humans to maintain healthy intestinal flora.  The intestinal flora plays important role in human health, being sensitive to various influences. Dysbiosis is a microbial imbalance resulting from e.g. stress, diet, antibiotics, and infections.  For the last decade researches have revealed good evidences on the importance of maintain healthy intestinal flora in sake of good health for the individual like preventing inflammation.  Altered intestinal flora has been associated with diseases such as heart diseases, asthma, obesity and many more.  There are limiting factors in relation to marketing probiotic products, which emphasizes the importance on continuing research for revealing therapeutic functionality on probiotic products.

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1 Hawrelak JA, Myers SP. The causes of intestinal dysbiosis: a review. Alt Med Rev 2004;9(2):180-197.

2 FAO/WHO. Probiotics in food. Health and nutritional properties and guidelines for evaluation. World Health Organization and Food and Agriculture Organization of the United Nations. Rome 2006. Report no: 85

3 Felis GE, Dellaglio F. Taxonomy of lactobacilli and bifidobacteria. Curr Issues Intest Microbiol 2007;8:44-61.

4 Kleerebezem M, Vaughan EE. Probiotic and gut lactobacilli and bifidobacteria: molecular approaches to study diversity and activity. Annu Rev Microbiol 2009;63:269-90.

5 Reddy RS, Swapna LA, Ramesh T, Singh TR, Vijayalaxmi N, Lavanya R. Bacteria in oral health – probiotics and prebiotics: a review. Int J Biol Med Res 2011;2(4):1226-1223.

6 Baugher JL, Laenhammer TR. Invited review: application of omics tools to understanding probiotic functionality. J Dairy Sci 2011;94:4753-4765.

7 Schrezenmeir J, De Vrese M. Probiotics, prebiotics, and synbiotics- approaching a definition. Am J Clin Nutr 2001;73:361s-364s.

8 Roberfroid M. Prebiotics: the concept revisited. J Nutr 2007;137:830S-837S.

9 Anderson H, Asp NG, Bruce A, Roos S, Wadstöm T, Wold AE. Health effects of probiotics and prebiotics: a literature review on human studies. Scand J Nutr/Naringsforsking 2001;45:58-75.

10 Clemente JC, Ursell LK, Parfrey LW, Knight R. The impact of the gut microbiota on heman health: an integrative view. Cell 2012;148:1258-1270.

11 The Human Microbiome Project Consortium. Structure, function and diversity of the healthy human microbiome. Nature 2012;486:207-2014.

12 Qin J, Li R, Raes J, Arumugam M, Burgdorf KS, Manichanh C, et al. A human gut microbial gene catalogue established by metagenomic sequencing. Nature 2010;464:59-65.

13 Eckburg PB, Bik EM, Bernstein CN, Purdom E, Dethlefsen L, Sargent M, et al. Diversity of the human intestinal microbial flora. Science 2005;308:1635-1638.

14 Sekirov I, Russell SL, Antunes LC, Finlay BB. Gut microbiota in health and disease.  Physiol Rev 2010;90:859-904.

15 Ley RE, Lozupone CA, Hamady M, Knight R, Gordon JI. Worlds within worlds: evolution of the vertebrate gut microbiota. Nature Rev Microbiol 2008;6:1635-1638.

16 Backhed F, Ley RE, Sonnenburg JL, Peterson DA, Gordon JI. Host-bacterial mutualism in the human intestine. Science 2005;307:1915-1920.

 17 Hooper LV, Midtvedt T, Gordon JI. How host-microbial interactions shape the nutrient environment of the mammalian intestine. Annu Rev Nutr 2002;22:283-307.

18 Ley RE, Turnbaugh PJ, Klein S, Gordon JI. Microbial ecology: human gut microbes associated with obesity. Nature 2006;444:1022-1023.

 19 Turnbaugh PJ et al. An obesity-associated gut microbiome with increased capacity for energy harvest. Nature 2006;444:1027-1031.

20 Ley RE, et al. Obesity alters gut microbial ecology. Proc Natl Acad Sci 2005;102:11070-11075. [abstract].

21 Sommer F, Bäckhed F. The gut microbiota – masters of host development and physiology. Nature Rev Microbiol 2013:1-12.

22 Aumeunier A, Grela F, Ramadan A, Phan Van L, Bardel A, et al. Systemic toll-like receptor stimulation suppresses experimental allergic asthma and autoimmune diabetes in NOD mice. PloS ONE 2010;5(7)e11484:1-14.

23 Leyer GJ, Li S, Mubasher ME, Reifer C, Ouwehand AC. Probiotic effects on cold and influenza-like symptom incidence and duration in children. Pediatrics 2009;124(2):e172-9.

24 Ataie-Jafari A, Larijani B, Alavi Majd H, Tahbaz F. Cholesterol-lowering effect of probiotic yogurt in comparison with ordinary yogurt in mildly to moderately hypercholesterolemic subjects. Ann Nutr Metab 2009;54:22-27.

25 Corr SC, Li Y, Riedel CU, O´Toole PW, Hill C, Gahan CG. Bacteriocin production as a mechanism for the antiinfective activity of Lactobacillus salivarius UCC118.

Proc Natl Acad Sci USA 2007;104:7617-21.

26 Murray M, Pizzorno J. Encyclopedia of Natural Medicine. Rocklin, CA: Prima Publishing; 1998:143.

27 Holzapfel WH, Haberer P, Snel J, et al. The fecal microbial population in the irritable bowel syndrome. Microbiologica 1982;5:185-194.

28 Ley RE, Hamady M, Lozupone C, Turnbaugh PJ, Ramey RR, Bircher JS, et al. Evolution of mammals and their gut microbes. Science 2008;320:1647-1651.

29 Roediger WE, Moore J, Babidge W. Colonic sulfide in pathogenesis and treatment of ulcerative colitis. Dig Dis Sci 1997;42:1571-1579.

 30 Carbonero F, Benefiel AC, Alizadeh-Ghamsari AH, Gaskins HR. Microbial pathways in colonic sulfur metabolism and links with health and disease. Front Physiol 2012;3(448):1-11.

31 Gibson GR. Dietary modulation of the human gut microflora using prebiotics. Br J Nutr 1998;80:S209-S212. [abstract].

32 Bailey MT, Coe CL. Maternal separation disrupts the integrity of the intestinal micro-flora in infant rhesus monkeys. Dev Psychobiol 1999;35:146-155.

33 Lizko NN. Stress and intestinal microflora. Nahrung 1987;31:443-447.

34 Holdman LV, Good IJ, Moore WE. Human fecal flora: variation in bacterial compositition within individuals and possible effects of emotional stress. Appl Environ Microbiol 1976;31:359-375.

35 Lyte M, Erickson AK, Arulanandam BP, et al. Norepinephrine-induced expression of the K)) pilus adhesion of enterotoxigenic Escherichia coli. Biochem Biophys Res Commun 1997;232:682-686.

36 Hegde M, Wood TK, Jayaraman A. The neuroendocrine hormone norepinephrine increases Pseudomonas aeruginosa PA14 virulence through the las quorum-sensing pathway. Appl Microbiol Biot 2009;84:763-776.

37 Roberts A, Matthews JB, Socransky SS, Freestone PPE, Williams PH, Chapple ILC. Stress and the periodontal diseases: effects of catecholamines on the growth of periodontal bacteria in vitro. Oral Microbiol Immun 2002;17(5):296-303.

38 Gismondo MR. Antibiotic impact on intestinal microflora. Gastroenterol Int 1998;11:29-30.

39 Nord CE. Studies on the ecological impact of antibiotics. Eur J Clin Microbiol Infect Dis 1990;9:517-518.

 40 Nord CE, Edlund C. Impact of antimicrobial agents on human intestinal microflora. J Chemother 1990;2:218-237. [abstract].

41 European Commission. Health and cunsumers. Health and Nutrition Claims. [Internet]. Updated 20 November 2011.

42 FAO/WHO. Guidelines for the Evaluation of probiotics in food. Report of a Joint FAO/WHO Working Group on drafting guidelines for the evaluation of probiotics in food. London, Ontario, Canada 30 April – 1 May 2002. Report no: 85.

43 Ovesen L. Regulatory aspects of functional foods. Eur J Cancer Prev 1997;6(5):480-2.

44 Stanton C, Gardiner G, Meehan H, Collins K, Fitzgerald G, Lynch PB, et al. Market potential for probiotics. Am J Clin Nutr 2001;73(2):476s-483s.

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