A recently published study that prompted researchers to call one-size-fits-all probiotics “quite useless” has drawn sharp criticism from the natural products industry.
Research by scientists at the Weizmann Institute of Science in Israel, published earlier this month in the journal Cell, showed that ‘probiotic resistance’ was likely to make probiotic supplements less effective than thought, and in some cases may produce long-term adverse effects. The study also suggests that current methods of measuring the persistence of probiotic bacteria may give misleading results.
The Weizmann Institute team say that the science around the efficacy of probiotics remains “very controversial”. They point out that most of the studies carried out to test how effective probiotics are at at colonizing the gastrointestinal tract have used stool samples to act as a proxy for microbe activity in the GI tract, while their own studies were based on investigations that measured gut colonization directly.
In the study, 25 volunteers underwent upper endoscopies and colonoscopies to sample their baseline microbiome in regions of the gut. Fifteen of those volunteers were then divided into two groups. The first group consumed an 11 strain probiotic preparation, while the second group received a placebo. Both groups then received second round of upper endoscopies and colonoscopies to assess their internal response before being followed for another 2 months.
“What we found was very surprising,” senior researcher, Erab Elinav, told The Guardian: “Of those who were given probiotics, we could group the individuals into two distinct groups: one which resisted the colonization of the probiotics, and one in which the probiotics colonised the gut and modified the composition of the gut microbiome and the genes of the host individual.”
“This tells us the currently used paradigm of one-size-fits-all probiotic preparation and treatment should be replaced by a tailored therapy which harnesses science and measurement and technology.”
Elinav told the BBC: “… just buying probiotics at the supermarket without any tailoring, without any adjustment to the host, at least in part of the population, is quite useless.”
“… just buying probiotics at the supermarket without any tailoring, without any adjustment to the host, at least in part of the population, is quite useless”
Dr Trevor Lawley, a microbiome researcher at the Sanger Institute, told the BBC he was not surprised by the findings. “Probiotics have been around for a long time and they’re coming under more scrutiny. The gut has a natural property to stop colonisation, as it usually blocks pathogens, and that is something we have to outmanoeuvre.”
Natural products industry groups and commentators have been quick to criticise the study’s findings, and the media coverage of it. Nathan Gray, a senior editor at the website nutraingredients.com, said the BBC’s coverage was of the type that was “potentially damaging to the sector and consumer understanding”. Grey said the BBC article made a “serious mistake” of “confusing colonization with efficacy”.
US trade body the Natural Products Association meanwhile attacked the researchers over what it called their “dangerous advocating” of faecal microbiota transplant therapy over “safe probiotic supplements”.
“There are good reasons why probiotics are taken by almost four million adults and prescribed by up to 60% of health care providers: they’re safe and effective”
Daniel Fabricant, president and CEO of the NPA commented: “There are good reasons why probiotics are taken by almost four million adults and prescribed by up to 60% of health care providers: they’re safe and effective.” By contrast, the NPA added, faecal transplants are associated “with a high rate of adverse events, including serious adverse events”.