Study cautions public to be wary of online probiotic claims

Most websites that provide information on probiotics are unreliable and claims of benefits against disease are often based on mice experiments, according to a new study published in the journal Frontiers in Medicine.

The authors caution that, while Google is adept at sorting the most reliable websites to the top of the list, many websites providing information on probiotics are from commercial sources.

Probiotics are live organisms that, if research holds its promise, could be beneficial to health. There is a large U.S. market for probiotics but less so elsewhere in the world, likely due to stricter regulation for health claims. Nevertheless, the market for probiotics continuously expands with the globalization of online sales.

Concerned that the public has unrealistic expectations about the beneficial effects of probiotics (bolstered by online claims and hype in the news), researchers led by Pietro Ghezzi, PhD, a professor at the Brighton and Sussex Medical School in England, decided to assess the information that the public were exposed to when searching online. They assessed the first 150 webpages brought up by a Google search for "probiotics,” and recorded where they originated from and the diseases they mentioned. The scientific evidence for health benefits of probiotics against these diseases were then examined for scientific rigor.

The researchers used the Cochrane library, a database of clinical trials and meta-analyses of evidence-based medicine, to assess the strength of scientific evidence found online.

News outlets and commercial sources made up the majority of the 150 webpages and the analysis showed these were the least reliable, often not mentioning the side effects on immunocompromised individuals nor any regulatory issues. In addition, the findings of experiments on mice were used to make claims about probiotic benefits against disease in humans.

Ghezzi explained that Google has developed very stringent criteria for ranking health-related websites, however, we should always question where the information originates from.

"Google prioritizes webpages containing more complete and scientifically robust information about probiotics, particularly health portals, and these are given a higher ranking than commercial websites,” he said. “However, the fact that there is such a large amount of commercially-oriented information is problematic for consumers who are searching for honest answers."