February 2018



    Probiotics represent a promising approach to improving human health as well as helping in the prevention and treatment of several diseases of clinical interest. Certain probiotics can down-regulate production of pro-inflammatory cytokines and promote intestinal epithelial barrier functions, increasing an anti-inflammatory response and contributing to the host’s overall health. The main mechanisms by which probiotic microorganisms can interact with the host are by modulating the immune system and the epithelial cell functions and interacting with intestinal gut microbiota. However, it is essential to clearly understand which characteristics a microorganism must possess to be used in the formulation of probiotic products, since numerous probiotics available on the market have no beneficial effects on human health and might contain some pathogenic and harmful traits. This paper intended to identify the main characteristics that probiotic microorganisms and products should possess to have a positive impact on the host’s health to allow for an assessment of any probiotic(s) under consideration.

    Here are the author’s “Golden Rules:”

    • Know the correct definition of probiotics: Probiotics are live microorganisms acting as powerful biomodulators, with a positive impact on human health. The official definition of probiotics given by the WHO (World Health Organization) is “live microorganisms which, when administered in adequate amounts, confer a health benefit to the host.”
    • Microbial lysates, non-living bacteria and non-colonizing spores cannot be considered probiotics, even though some have been observed to have a beneficial impact on the host’s immune system and health.
    • Only a well, fully characterized microbial strain should be used for the formulation of probiotic products, including claimed dosage, genetic typing and traceability. Commercial probiotic products currently on the market are not always correctly labeled, as many microorganisms which are claimed to be contained may not be present or their amount may be lower than that declared on the label.
    • Multi-strain products are not necessarily superior. Research on multistrain probiotic formulations should be based on those microorganisms showing in vitro synergistic and symbiotic activities, that if found to be more clinically effective would justify the use of multistrain products instead of monostrain ones.
    • The safety of commercial microbial strains should be assessed before they are marketed to evaluate not only the presence or absence of virulence factors, but also their ability of acquiring and transferring antibiotic resistance-genetic elements. Furthermore, all microorganisms contained in probiotic products should have a susceptible profile with no antibiotic resistance genes.
    • Only probiotic products containing microbial strains able to resist gastrointestinal conditions should be considered for human consumption.
    • A microorganism with a strong in vitro probiotic activity but unable to adhere and colonize the intestinal environment is not a good candidate for a probiotic product.
    • Even if there are few and conflicting data on the impact of probiotics on gut microbiota composition, only probiotic products with a strong intestinal activity and that positively interact with gut microbiota should be marketed.
    • Generally, the real risk in using probiotic products is related more to a compromised health status of the patient than to the microbial strain used in the probiotic product.
    • In the choice of the best probiotic species or strain to use in the presence of a given disease, much attention should be paid towards those microorganisms/strains for which clinical efficacy has been already demonstrated. Furthermore, clear legislation regulating probiotic production, as well as strict safety controls of all phases during the manufacturing of probiotics are needed to guarantee that only beneficial and well-characterized microorganisms are marketed. My Comment: One only has to go to the pharmacy or grocery store to see that sales and marketing of probiotics has become a huge industry. In most cases, the market is well ahead of the science. As healthcare professionals, it is important that we are grounded in the science that is known about this evolving area of medicine, and understand that there are not only potential benefits but also potential harms from ingesting large quantities of live bacterial cultures. Our understanding of the human microbiome and implications of that understanding continues to rapidly evolve.

    Carilion Clinic Department of Family and Community Medicine


    Reference: Toscano M. A consumer’s guide for probiotics: 10 golden rules for a correct use. Digestive and Liver Disease; 49(September 2017):1177–118. 

    Click on the link to review the article.  A Consumer Guide to Probiotics