Could Probiotics Soon Evolve And Cause More Harm Than Good?


It’s pretty common knowledge that these days you’ll find plenty of people taking regular probiotics in food or supplements in the hope of boosting their digestive health and immune system. But a new, small study suggests that some people may not benefit as much as others from these so-called good bacteria, and that the benefits of these probiotics may actually end up causing more harm than good in the long run.

Firstly, what exactly identifies as a Probiotic? Essentially, Probiotics are live bacteria that are consumed with the aim of improving or maintaining the microbiome, or the many “good” bacteria that are found naturally in our bodies, according to the Mayo Clinic.

A number of probiotic products are on the market currently, including a number of different varieties, including yogurts, supplements and skin creams, with an estimated 3.9 million people in America using these popular products alone.

During the new study, researchers discovered that, when people consumed standard probiotic bacterial strains, some people’s stomachs appeared to resist against the bacteria, meaning the bacteria failed to successfully live in or colonise their stomach. But for others, the bacteria readily grew and flourished in the stomach. Because of this, the study suggests that not everyone may benefit equally from standard probiotic treatments.

“This suggests that probiotics should not be universally given as a ‘one-size-fits-all’ supplement,” study co-senior author Eran Elinav, an immunologist at the Weizmann Institute of Science in Israel, said in a statement. However, it may be possible to tailor probiotic treatments to the individual, based on the types of microbes already in his or her gut, as well as other factors, so that he or she gets the most benefit from probiotics, according to the researchers involved in the study.

In addition to these findings, yet another study that recently took place suggested that probiotics could have a potentially harmful effect if taken after antibiotics. Because both studies were small, however, more research is needed to confirm the claim. Additionally, most studies on the topic that have looked at the effects of probiotics have used participants’ stool samples as a proxy for what’s going on inside their bodies, but it’s unclear whether stool samples really reflect the bacteria living in the stomach, or whether some bacteria are shed in stool more easily.

In the new study, the researchers analysed information from 15 healthy volunteers who took either a probiotic product containing 11 strains of bacteria, or a placebo product, for a total of four weeks. The participants also underwent colonoscopies and upper endoscopies before they took the probiotics or the placebo, and again after the four-week treatment period. During these procedures, the researchers took samples from inside participants’ stomach. During the study, researchers discovered that the probiotic bacteria were able to colonise the stomach in six participants. However, researchers also discovered that the remaining participants were “resisters,” meaning the bacteria did not colonise their stomach, even though the probiotic bacteria were shed in their stool.

“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,” co-senior author Eran Segal, a computational biologist at the Weizmann Institute, said in the statement. “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.”

Later, when further analysing the data discovered, the researchers also found that they could predict whether the probiotics would take hold in people’s stomach by simply examining their microbiome and gene expression in the stomach taken at the start of the study.

Since the study, the researchers involved have called for further research to be conducted to better understand why some people resist colonisation by probiotics, as that future research may enable researchers to counteract the resistance and conduct more studies accordingly.


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