International Probiotics Association responds to Washington Post article critical of probiotic supplementation

The International Probiotics Association (IPA; Dollard des Ormeaux, Quebec, Canada) has issued a response to a recent article from The Washington Post that called into question the benefits of probiotics, and suggested that probiotics may in fact have a negative impact on the gut microbiome. In its response, the IPA criticizes the author of misrepresenting the data by taking research out context. One study cited by the author, published in Cell, found that probiotics following antibiotics did not result in a recovered microbiome, but rather a less diverse microbiome compared to stool transplants and placebo. This led the author to conclude that use of probiotics may have no benefit, and actually reduce microbiome diversity.

“This is a false equivalency and is not at all supported by scientific evidence,” explains IPA. “Microbiome profiling is often performed in probiotic studies, but is not a clinically-accepted biomarker, and varies greatly in how it is performed, analyzed, and interpreted. Also, a recent scientific review paper on safety of probiotics discourages relying on microbiome profiling as a safety assessment. Thus, while lower diversity in the gut microbiota is generally linked to several health problems, no evidence has been provided by the author to demonstrate that probiotics can lower the diversity and thus cause health problems.”

The paper itself was previously criticized by the International Scientific Association for Probiotics and Prebiotics (ISAPP) as well for its methodology. The main takeaway from ISAPP and IPA is that the study did not actually track clinical endpoints, just microbiome data, which is therefore not evidence of a lack of clinical or physiological effects. They also point out that the treatments were administered seven days after treatment. This is important because probiotics are recommended for use before or during treatment with antibiotics, not after, as a preventive measure. This means that the results of the study do not necessarily constitute a real-world scenario.

Considering this, IPA points out: “It is antibiotics that cause damage to the microbiota, not probiotics.”

The article also suggested that consumers add more fermented food to their diets rather than buy and consume probiotics. While there is nothing wrong with adding fermented food to one’s diet, IPA points out that fermented foods do not in fact contain probiotics, nor do they consistently contain beneficial microbes. “Unless the microbial components have demonstrated a health benefit in a good quality clinical trial at the strain level, the microbes in fermented foods should be considered beneficial dietary microbes, not probiotics,” writes IPA. “Fermented foods by default also do not necessarily contain prebiotics or postbiotics, as they do not typically list specific microbial components, nor their live microbial content through to end of shelf life. It is also noteworthy that not all fermented foods contain live microbes if they have been heat treated or pasteurized. Furthermore, fermented foods may contain an uncharacterized synbiotic culture of bacteria and yeast, so inconsistencies may occur between batches depending on the manufacturing process.”

Arguably, IPA argues, the composition of fermented foods is more complex and less known compared to probiotic products that have higher levels of standardization.

Ultimately the message IPA drove home in its response is the fact that probiotics as a class of ingredients are well established and well researched despite what the article claims. “Underpinning this multibillion-dollar industry are over 1600 registered probiotic clinical studies, over 700 indications for probiotic supplements, and millions of probiotic doses taken daily around the world by a variety of individuals, with no reported deaths in healthy people due to probiotic supplementation to date,” says IPA. “Probiotic foods and dietary supplements are regulated around the world with a variety of safe lists, and a number of quality and manufacturing procedures. This is not hype, this is a science-backed, established industry.”

IPA’s full response can be read here.