The widely accepted scientific definition of probiotics is: “Live microorganisms that, when administered in adequate amounts, confer a health benefit on the host”. Host can refer to humans and animals. Probiotics are most known for their benefits for gut health. In addition, within the last decade, probiotics have gained attention for their contribution to improved skin health, vaginal and urinary tract health as well as other benefits.
The most well-known probiotics belong to the lactic acid bacteria. Adequate characterization of a probiotic is essential, as different strains of the same species or genus may not have the same health benefits. Probiotics are currently studied for their way of working applying in vitro models as well as animal and human studies in combination with microbiome profiling techniques and genome sequencing to define in more detail their potential effects on specific health outcomes via microbiome modulations and intracellular mode of action.