Claiming that probiotics are useless is not only senseless but also irresponsible. This is according to George Paraskevakos, Executive Director of the International Probiotics Association (IPA), responding to a study that claims probiotics might not be as effective as many think. There are myriad studies underlining the efficacy of probiotics, he says, with platforms now far extending beyond the traditional area of gastrointestinal (GI) health and research moving toward treatment, rather than prevention objectives.
The study in question, published as two back-to-back papers last week in the journal Cell, has caught the attention of the mainstream media, with outlets such as the Guardian reporting on it. Through a series of experiments looking inside the human gut, the researchers aimed to show that many people's digestive tracts prevent standard probiotics from successfully colonizing them. Furthermore, taking probiotics to counterbalance antibiotics could delay the return of normal gut bacteria and gut gene expression to their naïve state.
In the first study, 25 volunteers underwent upper endoscopies and colonoscopies to sample their baseline microbiome in regions of the gut. Fifteen of those were then divided into two groups. The first group consumed generic probiotic strains, while the second was given a placebo.
The scientists discovered that the probiotics successfully colonized the GI tracts of some people, called the “persisters,” while the gut microbiomes of “resisters” expelled them. They also found that stool only partially correlates with the microbiome functioning inside the body, so relying on stool, as was done in previous studies for many years, could be misleading.
“Although all of our probiotic-consuming volunteers showed probiotics in their stool, only some of them showed them in their gut, which is where they need to be,” says senior author Eran Elinav, an Immunologist at the Weizmann Institute of Science in Israel. “If some people resist and only some people permit them, the benefits of the standard probiotics we all take can't be as universal as we once thought. These results highlight the role of the gut microbiome in driving very specific clinical differences between people.”
In the second study, the researchers questioned whether patients should be taking probiotics to counter the effects of antibiotics, as they are often told to do in order to repopulate the gut microbiota after it's cleared by antibiotic treatment.
After the antibiotics had cleared the way, standard probiotics could easily colonize the gut of study participants, but to the team's surprise, this probiotic colonization prevented the host's normal microbiome and gut gene expression profile from returning to their normal state for months afterward. In contrast, participants treated with an autologous fecal microbiome transplant (aFMT) saw their native gut microbiome and gene program returning to normal within days.
Following these results, the researchers posited that the use of probiotics could cause potential adverse side effects when combined with antibiotics that might even bring long-term consequences.
However, in response, Paraskevakos questions the clinical validity of the study.
“It is amazing to me how the press doesn’t take the time to read to a bit deeper into the study, or studies that we have seen published over the last year. There have been one or two [negative studies] about probiotics. I think the study confuses colonization with efficacy. This study was limited to microbiome data,” he notes. “There are a lot of issues that raise flags within the probiotics community that the researchers might not have been experts in this space.”
“Looking at the product in detail, I think that there are some methodology issues that it was not set up as a clinical trial. I believe that not naming the product properly -- it was a formulation of 11 strains – [is an issue],” he says.
Although there are clinical studies on blends, the product used in the research in question had 11 strains which were not itemized.
“None of strains or species in the blend had any clinical justification against it. This raises issues in terms of how the study was set up, and what was claimed. To then publish outcomes that were against the probiotic industry resulted in the mass media sensationalizing it,” he notes.
“There’s a lot of evidence of how probiotics are beneficial. Not only in a general sense, but also for aspects such as gastrointestinal health. The amount of studies published over the past years about very specific health benefits is incredible,” he states.
IPA has funded research and just looking at two databases – clinicaltrials.gov and the WHO database – show over 1,200 studies that come out showing health benefits. To say that they are useless is not only senseless but also irresponsible. You’re misleading government agencies, the press and, of course, consumers,” he says.
Emerging platforms
Probiotics have gone far beyond digestive health in recent years, potentially creating some skepticism in terms of the sheer vastness of the supposed health benefits.
“[Probiotics] are not a magic bullet to health,” Paraskevakos notes in response. “However, anybody publishing or commercializing a product with a specific health benefit must make sure that what that benefit is justified with science.”
“Emerging trends in probiotics are originating from what we are seeing in the science,” he says.
“We are starting to see companies doing specific trials on disease states [such as metabolic diseases], not as prevention, but as treatment. Only time will tell whether are not these trials will be successful, but there is huge investment in that area,” he concludes.
