The article, published in The Washington Post in March, stated: “Studies show that taking probiotic supplements — for overall health or to counter the effects of antibiotics — can alter the composition of your microbiome and reduce the levels of microbial diversity in your gut, which is linked to a number of health problems.”
The author suggested that “in healthy people, probiotic supplements offer little benefit, and they can potentially do more harm than good”.
However, an industry body has hit back, saying this claim is misrepresentative.
Critics point to ‘false equivalency’
The International Probiotics Association (IPA), a global non-profit organisation representing the probiotic sector, described the assertion as “a false equivalency” that was “not at all supported by scientific evidence”.
In a statement released in response to the Post article, it said: “Microbiome profiling is often performed in probiotic studies, but is not a clinically accepted biomarker, and varies greatly in how it is performed, analysed, 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 ‘hype’ of probiotics is real, says IPA
The Post article warned consumers to “beware the hype” around probiotic supplements, adding that they “have grown into a multibillion-dollar industry, spurred by claims that the products will populate your gut with bacteria that can boost your health in numerous ways”.
It said that as many probiotics contain a “limited number of bacterial strains”, taking concentrated doses of them could upset the balance in the gut, leading to dysbiosis.
But the IPA questioned the author’s choice of language.
“Underpinning this multibillion-dollar industry are over 1,600 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,” it said.
“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.”
Probiotic use alongside antibiotics: Findings ‘taken out of context’
The IPA also challenged the article’s assessment of a 2018 study in Cell that looked at probiotic use alongside antibiotics – the idea being that the probiotic supplement helps to rebalance the gut microbiome and minimise any side effects associated with the antibiotic.
The Post reported that the study concluded that the microbiomes of people who took the probiotics had not returned to normal after five months, while they also had less gut microbiome diversity compared to people in the control or transplant groups.
However, the IPA said: “The Suez et al paper from 2018 has already been dismantled by scientific experts but suffice to say that the paper is misquoted and the data has unfortunately been taken out of context yet again.
“The design of the study was such that all groups experienced significant damage to their microbiota by antibiotic administration and then the treatments – including a probiotic – were applied.
“The reality is that most doctors recommend a probiotic at the latest during antibiotic treatment if not before to help mitigate the damage of antibiotics. It is antibiotics that cause damage to the microbiota, not probiotics.”
It added that the results of a 2023 study quoted in the Post article “have been also taken out of context”.
Efforts ‘should focus on positive research’
While the IPA acknowledged that taking a probiotic supplement “is indeed a concentrated dose of microbes”, when compared to the number of microbes that reside in the innate gut microbiota, it amounted to “a drop in the ocean”.
It added: “It is well accepted within the scientific community that probiotics do not colonise and are not detectable after seven to 14 days of cessation of administration; they also do not have the capacity to eliminate species already entrenched in the gut microbiota.”
In its closing comments, the IPA concluded: “The Washington Post should focus their efforts to highlight positive research regarding immunity, gastrointestinal, and overall health instead of relying on social media evidence to fearmonger among consumers who seek to derive benefit for their gut and overall health.”
