Rocky Road Ahead for Probiotics

Lactobacilus AcidophilusThere is a seeming paradox in the probiotic field between compelling research and allowable product claims. PubMed retrievable human studies investigating the clinical benefits of probiotics exceed 1,100. More than  60 meta-analyses or systematic reviews have been published on probiotics, many of which indicate that results are promising; at least one professional organization has developed practice guidelines for probiotic use (World Gastroenterology Organisation); and media personalities such as Dr. Oz recommend probiotics to followers. Yet, not a single claim for probiotics has been approved in Europe. And in the U.S., the Federal Trade Commission has issued actions (Dannon, Nestle) against probiotic companies for misleading advertising, while  litigators have decided that probiotic health benefit claims are fertile ground for class action lawsuits. Unfortunately, these efforts seem to target the companies that actually have some good data on their products; other companies – less appealing targets perhaps due to the depth of their pockets – are left to make wholly unsubstantiated claims.

Probiotic science is neither as superb nor as dreadful as these recent developments suggest.

This situation, seemingly inspired by Dr. Doolittle’s Pushmi-pullyu, is perhaps best understood by saying that probiotic science is neither as superb nor as dreadful as these recent developments suggest. Certainly, there are limitations in the science. Better characterization of the microbiota and host genome of subjects enrolled in human studies might help clarify the responders and non-responders for a specific probiotic intervention. In some cases, magnitudes of effects are small and may be lost in the noise of a human study. Studies are often underpowered, resulting in primary endpoints that show no statistically significant improvement. But probiotics are also caught in the crossfire of regulatory agencies that erect roadblocks to human research, not acknowledging the legal right to conduct human research in the U.S. on probiotic-containing foods and supplements; or processes for reviewing claims in Europe with seemingly unreasonably high bar for studies on foods and supplements (  In the U.S., FDA does not see foods as useful for the dietary management of symptoms, for improving absorption or reducing side effects of drugs (even though your prescription medication can specifically state “take this medication with food”), or for managing pathogen transmission in institutions plagued with nosocomial threats to patients. Such uses would all be seen as drug uses.

It is the plight of probiotics that such uses are also the types that have been studied for probiotic foods and supplements. In the U.S., these products are left making unsatisfying claims such as “helps support digestive health,” which tell consumers and healthcare providers little about the science behind the product. The FDA simply states that products seeking to have such effects take the long, expensive drug path to market. Unfortunately, the food companies aren’t interested. So in the end, it is the consumer who will suffer when research in this category wanes and yogurt becomes just another food to consume because it tastes so good.

Related reading:

Katan MB.Why the European Food Safety Authority was right to reject health claims for probiotics. Benef Microbes. 2012 Jun 1;3(2):85-9.

Sanders ME, Heimbach JT, Pot B, Tancredi DJ, Lenoir-Wijnkoop I, Lähteenmäki-Uutela A, Gueimonde M, Bañares S. Health claims substantiation for probiotic and prebiotic products. Gut Microbes. 2011 May-Jun;2(3):127-33