Probiotics and Prebiotics
Probiotics, which are meant for life in Greek, can be described as living microorganisms that balance the intestinal flora when taken in certain amounts with nutrients and affect the host's health positively. Another name given to probiotics is 'biogenics' (Holzapfel & Schillinger, 2002).
Definitions used in the literature for probiotics:
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The probiotic term, consisting of two parts, “Pro” and “biota”, means “for life” and is the antithesis of antibiotics (Patterson & Burkholder, 2003).
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Microorganisms added to foods that affect the host physiology positively by organizing the microorganism and nutritional balance in the intestines, and regulating systemic and mucosal immunity (Coşkun, 2006).
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Probiotics, nonpathogenic-living organisms, are able to reach to the colon since they are resistant to digestion against to the acidic environments of stomach. Thus it can positively affect the human health by influencing microbiota.
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Probiotics are live-food additives that affect the balance of the intestinal microorganisms of the host. (Watson, Preedy, Monedero, & Rodríguez-Díaz, 2016).
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Apart from simple nutritive properties, they are living microorganisms that are beneficial to the host's health when taken in sufficient quantities (Shah & Lankaputhra, 1997).
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Probiotics are organisms and substances contributing to the intestinal microorganism balance (Watson, Preedy, Likotrafiti, & Rhoades, 2016).
Prebiotics are indigestible components that increase the number and activities of beneficial bacteria living in the gut and the effect of probiotics. The classical definition of the prebiotic is that non-digestible nutrient components which have impacts on the host's health positively by increasing the number and type of bacteria in the colon. This term was first used by Gibson and Roberfroid in 1995. However, the emergence of prebiotics dates back to the 1950s. György and colleagues described a bifidogenic factor that selectively stimulates the proliferation of bifidobacteria. (Gyorgy, Mello, Torres, & Barness, 1953). Prebiotic food is a food product that contains a prebiotic component. The prebiotic components are oligosaccharides or polysaccharides which are mainly found in the carbohydrate group and generally function as soluble fibers. Prebiotics usually are found in the form of fructose and galactose polymers (Coşkun, 2006). There are four main groups of common prebiotics commonly used in Europe: inulin, fructooligosaccharides, lactulose, galactooligosaccharides. The most common oligosaccharides added to foods are fructooligosaccharides, galactooligosaccharides and polydextrose. Prebiotics affect the composition and activity of intestinal microbiota positively, by regulating intestinal motility, increasing the absorption and bioavailability of minerals, such as calcium and magnesium, and preventing the proliferation of pathogenic microorganisms. In order to define a food component as aprebiotic, it must have the following properties:
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Must be resistant to digestion,
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Must be hydrolyzed by bacteria present in the colon,
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Stimulate the growth of beneficial bacteria in the colon
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There must be positive effects on the host’s health. (Agostoni et al., 2004; Manning & Gibson, 2004).
The positive effects of probiotic microorganisms on human health were first introduced by Nobel Prize-winning Russian researcher, Elie Metchnikoff in 1908. Years ago, Metchnikoff realized that Bulgarian villagers had lived longer. When he investigated the reaoson for that, he found that they consumed plenty of yoğurt. When he examined the yoğurt, he found live bacteria on it and he called it as Lactobacillus bulgaricus (Taşdemir, 2017). Probiotics plays an important role in the gastrointestinal system physiology. These non-pathogenic live microorganisms are using to support the immune system, to regulate the intestinal system, to improve digestion and absorbsion of food components including vitamins and minerals, to inhibit pathogenic bacteria and viruses, to prevent tumor formation, to prevent diarrhea, to reduce lactose tolerance (Tamime & Marshall, 1997; Vinderola, Prosello, Ghiberto, & Reinheimer, 2000).
In order to consider a microorganism as a probiotic, the following properties need to be evaluated.
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To have non-invasive and non-carcinogenic properties for the host,
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To be human origin,
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To be resistant to stomach acid and bile,
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To attach to the intestinal epithelium cell,
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To have clinical effects on health,
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To colonize temporary in the gastrointestinal tract,
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To be able to adapt to natural flora,
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To be suitable for experimental studies (a stable strain, able to survive, culturally obtainable, resistant to oxygen, lyophilized),
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To be able to produce antimicrobial substances (bacteriocins, hydrogen peroxide etc) (Coşkun, 2005; Fioramonti, Theodorou, & Bueno, 2003).
The most studied microorganizms considered as probiotics in the worldwide are Lactobacillus (Lactobacillus acidophilus, L. casei, L. buchneri, L. fermentum, L. delbrueckii subsp. bulgaricus, L. plantarum, L. reuteri, L. johnsonii, L. rhamnosus, L. salivarius, L. crispatus, L. curvatus), Bifidobacterium (B. bifidum, B. adolescentis, B. animalis, B. infantis, B. longum and B. breve), Enterococcus (E. faecium and E. faecalis) and Streptococcus, S. intermedius and S. diacetylactis) (Doğan, 2012; Duwat, Cesselin, Sourice, & Gruss, 2000).
The products formed by the use of probiotics and prebiotics are called synbiotics. With synbiotic application, probiotic bacteria can survive longer and can proliferate better in the colon. The aim of the using synbiotic products is to increase the beneficial effects of bacteria on host’s health. In vitro study findings support this idea that using the synbiotic applications have more advantages than either prebiotic or probiotics alone (Bruzzese, Volpicelli, Squaglia, Tartaglione, & Guarino, 2006; Ewaschuk & Dieleman, 2006).