Probiotics and antimicrobial peptides: the creatures' and substances' future in the twenty-first century: an opinion letter.

While the number of scientific publications related to health-promoting bacteria and antimicrobials of proteinaceous nature is growing, there is an obvious need for a better comprehension of what these studies actually provide the community and which directions these studies should be taking. With no intention of neglecting fundamental science (in which true knowledge helps separate fact from fiction, and eventually finds its practicality), I would still like to step on a dangerous path and speculate on the near-future progress in the aforementioned field of science with emphasis on possible beneficial outcomes. The number of marketed food products and dietary supplements labeled as ‘‘probiotics’’ or ‘‘containing probiotic bacteria’’ is virtually incalculable. In 2010, the global probiotic market was estimated at $22.6 billion and is projected to reach $28.8 billion by 2015 [1]. Very few microorganisms have been subjected to thorough in vitro studies confirming their specific health-promoting activity, and even fewer were subsequently subjected to and passed the appropriate human trials. A few studies of interest include those which investigated the strains Lactobacillus plantarum 299v, Lactobacillus casei Shirota, Lactobacillus rhamnosus GG should probably be mentioned—yet even the latter was reported on several occasions as associated with bacterial sepsis (for review see: [2]). Additionally, probiotics can be truly dangerous, posing as a wolf in the sheep’s clothing: They have been linked to an increase in mortality rate if administered to severely immunocompromised patients [3]. Those interested in ‘‘legal’’ probiotics may consider looking at the list of so-called ‘‘Commercial Strains Sold As Probiotics’’ [4] where the phrase ‘‘sold as’’ is perhaps the most telling in indicating the less that firm certainty about these strains being large-scale human trialproven as delivering measurable benefits. Still, there is WHO guidance on probiotics [5] and a brief overview of the claims discussed as required and sufficient for placing a microorganism into a group of ‘‘good fellows’’ [6]. Finally, NIH Grant 5R01HG005171-02 resulted in a document entitled ‘‘Federal Regulation of Probiotics: An Analysis of the Existing Regulatory Framework and Recommendations for Alternative Frameworks’’ [7] which only confirms the murky reality of less than stringent and frequently disconnected regulations currently being observed. As of December 14, 2012, the European Food Safety Authority (EFSA) posed serious and soundly justified [8] restrictions on labeling food products containing probiotics—the matter was strongly opposed by the major world manufacturers of microorganism-fermented/containing food products and by the large-scale manufacturers of microbial cultures [9]. Currently, there are two (European and North American) different statuses resulting in two different approaches addressing the real problem: how to separate the truly beneficial microorganisms from the crowd of overall harmless but ‘‘indifferent’’ bugs broadly used to make some products attractive to the consumers [10]. All of these leave a few questions and hopefully some answers. The diversity and multiplicity of the human microbiota cannot be ignored. While broad generalizations can be made concerning the frequency of certain species in our body’s ecological niches, they are genetically variable [11]. Certainly, the common strains associated with healthy human subjects should do no harm when ingested with a food product or administered otherwise. The additional health benefits are somewhat doubtful; why should they deliver anything in addition to what they already provide? M. L. Chikindas (&) School of Environmental and Biological Sciences, Rutgers State University, New Brunswick, NJ 08901, USA e-mail: tchikindas@AESOP.Rutgers.edu