A Microbiome Bust? Lack of Probiotic Benefit for Acute Pediatric Gastroenteritis

William F. Balistreri, MD


January 31, 2019

In This Article

Probiotics, live microorganisms administered with the intent of inducing a beneficial effect in the host, have been recommended by healthcare professionals to treat a wide variety of diseases in clinical practice.[1,2,3] Probiotic preparations are also commonly consumed by healthy individuals simply in hopes of achieving various health benefits, improved quality of life, and disease prevention. The market for probiotics has therefore expanded into a multibillion-dollar industry offering an increasing variety of preparations.

The rationale for the use of these products is based in part on the observation that the composition of the microbiome (endogenous microflora) has broad effects on health and disease. It is postulated that in ailments as varied as obesity, autoimmune disorders, and infectious diseases, harmful bacteria predominate.[4]Thus, probiotics have become a primary tool for realizing the therapeutic goal of reversing presumed "dysbiosis"—replace harmful microflora with beneficial microorganisms.

It may not be a simple matter of "good bugs in, bad bugs out," however; there clearly are strain-specific effects. For example, a specific probiotic strain, Lactobacillus rhamnosus, has been reported to be beneficial in a wide variety of conditions, including antibiotic-associated diarrhea, Clostridium difficile–associated diarrhea, weight loss, and necrotizing enterocolitis in preterm babies.[1,2,3,5] Thus, when interpreting the results of a clinical trial, consideration must be given to the composition and content of the probiotic strain administered.

A key obstacle to this critical interpretation is the fact that the microbial identity/content, purity, strength, and composition of probiotic products, as well as their efficacy and safety, are not subjected to review and approval by the US Food and Drug Administration. In addition, consumers may not be aware that probiotics may present risks for allergic reactions and opportunistic infections.[1]

Despite the absence of evidence, probiotics are freely promoted as supplements that confer a health benefit. Scientists and clinicians have questioned whether there exists enough evidence to support the myriad claims and have called for high-quality independent studies.[1,3,6]


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