| Scientist - News - 19-05-2008: Probiotic combinations may be less effective than single strains Beintema, Nienke Finnish researchers examined the impact of eleven bacterial strains on human immune system parameters. They investigated the effects of these strains alone and in combinations. Their aim was to identify potential enhancing or synergistic effects. However, they found no such effects, and suggest that different strains may compete with each other. The Finnish researchers analysed cytokine production – an important measure of immune system activation – in human blood cells, in response to stimulation with eleven different potentially probiotic bacterial strains. These strains came from six bacterial genera: Streptococcus, Lactobacillus, Bifidobacterium, Lactococcus, Leuconostoc and Propionibacterium. The team examined four different cytokines: IL-10, IL-12, IFN-g and TNF-a. They found that the cytokine response depended on the kind of bacterial strain. All bacterial genera enhanced TNF-a production. Streptococcus and Leuconostoc were found to be the best inducers of IL-12 and IFN-g, while Bifidobacterium and Propionibacterium strains induced the highest IL-10 production. Lactobacillus, a probiotic commonly used in dairy products, induced significantly less cytokine response. Interestingly enough, the Fins found that bacterial combinations did not result in any enhanced effects. They suggest that different bacterial strains compete with each other, offsetting some of the positive effect that each strain has individually. The authors stress that this is one of the few studies comparing cytokine effects of probiotic bacteria and their combinations within the same experiment. The team, which included researchers from the Finnish National Public Health Institute, Valio Research Centre and the University of Helsinki, published their findings in the February issue of the World Journal of Gastroenterology. For more information: World Journal of Gastroenterology «Back |