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Microorganisms. 2019 Apr 11;7(4). pii: E104. doi: 10.3390/microorganisms7040104.

Probiotics: If It Does Not Help It Does Not Do Any Harm. Really?

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B. Rappaport School of Medicine, Technion-Israel Institute of Technology, Haifa 3200003, Israel.
AESKU.KIPP Institute, 55234 Wendelsheim, Germany.
The Zabludowicz Center for Autoimmune Diseases, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel-Aviv University, Tel Aviv 5262000, Israel.
AESKU.KIPP Institute, 55234 Wendelsheim, Germany.


Probiotics per definition should have beneficial effects on human health, and their consumption has tremendously increased in the last decades. In parallel, the amount of published material and claims for their beneficial efficacy soared continuously. Recently, multiple systemic reviews, meta-analyses, and expert opinions expressed criticism on their claimed effects and safety. The present review describes the dark side of the probiotics, in terms of problematic research design, incomplete reporting, lack of transparency, and under-reported safety. Highlighted are the potential virulent factors and the mode of action in the intestinal lumen, risking the physiological microbiome equilibrium. Finally, regulatory topics are discussed to lighten the heterogeneous guidelines applied worldwide. The shift in the scientific world towards a better understanding of the human microbiome, before consumption of the probiotic cargo, is highly endorsed. It is hoped that better knowledge will extend the probiotic repertoire, re-confirm efficacy or safety, establish their efficacy and substantiate their beneficial effects.


probiotics, autoimmune disease, horizontal gene transfer, virulent factor, antibiotic-resistant genes, public health

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