do probiotic preparations for humans really have efficacy?

Microbial ecology studies have provided convincing evidence for the crosstalk between members of the autochthonous microbiota and the host immune system. The tight interrelationship between microbiota and host mucosal cells are mediated by microbial metabolites that are responsible for bacterial cell-to-cell communication by quorum-sensing mechanisms and also through the activation of eukaryotic cells following secretion of host defensins and modulation of cytokine expression profiles. All these host functions can be positively influenced by probiotic bacteria of human origin. However, few requirements for evaluating these strains for use in humans have been set according to their composition and metabolic activity. In this article, we have reported the scientific data published to date on the advantages of either mono- or multispecies probiotic products based on the outcome of the most significant clinical trials. According to published clinical trials, the efficacy of probiotic intervention for infectious or antimicrobial treatment-induced diarrhea, caused by different opportunistic bacterial or viral pathogens, was 48%. The probiotic preparations’ efficacy for silencing the clinical symptoms of IBS was 75% and for attenuating the inflammatory response during IBD was 83% whereas multistrain probiotics appear to have better efficacy.This article has been commented on by Tore Midtvedt, Editor-in-Chief. Please follow this link http://www.microbecolhealthdis.net/index.php/mehd/article/view/11620 to read his Editorial Remarks