The synbiotic concept was first defined along with prebiotics in 1995 by Gibson and Roberfroid, 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, by selectively stimulating the growth and/or by activating the metabolism of one or a limited number of health-promoting bacteria, thus improving host welfare.”1
The objective behind this concept is to enhance the survival and effect of probiotic strains in the gut that are already documented for their modes of action and benefits in humans. Based on the example of a synbiotic developed to reinforce children’s digestive microflora and protect their health, this article gives an insight into synbiotic formulation and its benefits.
Synbiotic formulation for children
Children have a totally different microbiota profile than adults. While bifidobacteria species are less important in adults, they are the predominant bacterial species in breastfed babies. According to many studies, bifidobacteria may play an important role in maintaining the intestinal microflora balance in children.2 Thus, when designing a child-specific formula, bifidobacteria appeared as the obvious choice. Two different strains were selected from Rosell’s culture collection: Bifidobacterium Rosell-71 and Bifidobacterium Rosell-33. These strains survive the digestive process, have the ability to adhere to epithelial cells, and have been recognized for their barrier effects and ability to inhibit pathogen attachment to the gut wall. In addition, it has been shown that Bifidobacterium Rosell-71 seems able to modulate some immunological parameters of inflammation. Moreover, Bifidobacterium Rosell-33 has the ability to inhibit intestinal pathogens. It has been shown to strongly inhibit growth of Staphylococcus aureus, Listeria monocytogenes, Clostridium difficile, Salmonella typhimurium, Clostridium perfringens and Escherichia coli.
Since their immune system is still developing, we know that children are usually more susceptible to pathogen challenges than adults. For this reason, a third probiotic strain known for its strong anti-pathogenic effect was added to the formula—Lactobacillus Rosell-52. This strain, which is one of the most studied probiotic strains, substantiated by many in vivo, pre-clinical and clinical studies, also has the ability to modulate the immune response. Studies have shown that Lactobacillus Rosell-52 has the ability to compete with pathogens and to alter the host responses to microbial pathogens through multiple mechanisms of action, including the reduction of mucosal inflammation by promoting the anti-inflammatory host responses.3
The reason why strains from different genera and species were selected is that the distribution of microbial species along the gut varies according to their ability to resist oxygen, acid and bile salts. Hence, the combination of lactobacilli and bifidobacteria allows for the probiotic effects to be exerted in both the distal end of the small intestine and throughout the colon, thus being able to balance the whole intestinal flora.
Why prebiotics matter
In order to maximize the survival and effects of the probiotic and to favor the growth and activity of resident bifidobacteria, a prebiotic was selected to complete the formula. Prebiotics are non-digestible oligosaccharides that are able to selectively stimulate the growth and/or activity of one or a limited number of bacterial species, either endogenous or probiotics. Among them, fructo-oligosaccharide (FOS) is one of the most widely used prebiotics and was chosen for its bifidogenic effect—the ability to increase bifidobacteria population in the gut. Indeed, FOS is selectively digested by bifidobacteria in the colon.4 Breast milk contains relatively high levels of FOS and it has been shown that the population of bifidobacteria is ten times higher in the gut of breastfed babies as compared to those who are fed on formula. Being widely used, we also know that FOS is well tolerated by all populations.
A 2010 review of published clinical studies on the health benefits of probiotics reported that the prebiotic effect was associated with modulation of biomarkers and activity(ies) of the immune system. Confirming the studies in adults, it has been demonstrated that, in infant nutrition, the prebiotic effect includes a significant change of gut microbiota composition, especially an increase of fecal concentrations of bifidobacteria. Such evidence favors the choice of a synbiotic formula to potentially enhance children’s defenses.
The efficacy of our synbiotic formula to enhance children’s defenses and prevent common infections was evaluated by a randomized double-blind placebo-controlled study.5 The study involved healthy, school-age children who had suffered from at least three episodes of ear-nose-throat (ENT), bronchopulmonary or gastric disorders during the course of the previous winter. Children were supplemented daily with either the synbiotic preparation or a matched placebo for three months.
This study suggested that the synbiotic supplementation was able to significantly decrease the risk of occurrence of common infectious diseases in children by 25 percent and limit school absenteeism due to these episodes by 40 percent.
No side effect was observed in this study, confirming the safety of the supplement.
Several in vivo studies with the selected bacteria strains alone or in combination support the observed benefits and help explain possible modes of action. Most recently the synbiotic formula has been described for its ability to modulate the two types of immune response Th1 and Th2 in animal models.6
While probiotics are well documented for their benefits in various health areas, in particular gut health and increasingly in immune support, it appears that the synbiotic concept is very promising but still in its infancy. Indeed, worldwide experts that gathered at a workshop at Yale University stated that further evidence is still needed to prove that they actually work better than probiotics alone.
1. Gibson GR, Roberfroid MB. Dietary modulation of the human colonic microbiota: introducing the concept of prebiotics. J Nutr. 1995 Jun;125(6):1401-12.
2. Bartram HP, Scheppach W, Gerlach S, Ruckdeschel G, Kelber E & Kasper H (1994): Does yogurt enriched with Bifidobacterium longum affect colonic microbiology and faecal metabolites in healthy subjects. Am. J. Clin. Nutr. 59, 428-432.
3. Johnson-Henry K.C., et al. Amelioration of the Effects of Citrobacter rodentium Infection in Mice by Pretreatment with Probiotics. The Journal of Infectious Diseases 2005; 191:2106–17.
4. Mitsuoka et al. (1987): Effect of fructooligosaccharides on intestinal microflora. Die Nahrung, 31, 427-36.
5. Cazzola M, Pham-Thi N, Kerihuel JC, Durand H, Bohbot S. Efficacy of a synbiotic supplementation in the prevention of common winter diseases in children: a randomized, double-blind, placebo-controlled pilot study. Ther Adv Respir Dis. 2010a - October 2010 vol. 4 no. 5 271-278.
6. Cazzola M, Tompkins T.A. and Matera M. G. Immunomodulatory impact of a synbiotic in TH1 and TH2 models of infection Ther Adv Respir Dis 2010b - vol. 4 no. 5 259-270.