For as long as we can remember, probiotics have been the poster child for gut health. Just pop one of these babies daily and you’ll be well on your way to a flatter belly and improved digestion, right? Well, maybe not. According to new research from Israel’s Weizmann Institute of Science, probiotics not only do sweet nada for improving your gut health, but they can actually make it worse.
The two studies published in the journal Cell investigated the effectiveness of probiotics, and whether they really can restore the good bacteria in someone’s gut after a course of antibiotics. In the first study, participants were put into two groups. One was given a commercial probiotic, and the other was given a placebo.
When the researchers analysed their bacteria through an upper endoscopy and colonoscopy, they found that the probiotics caused one of two responses. The bacteria either traveled from one end to the other without attaching to the gut (aka. it did nothing) or it only caused minimal changes to the microbiome.
In the second study, participants were given either commercial probiotics or a transplant of their own gut bacteria (taken before the study) following a course of antibiotics. There was also a third group, who were given no further treatment after their antibiotics. Compared to the first study, the probiotics were significantly better at colonising in the gut after antibiotics. But—and here’s where it gets interesting—the researchers found that the probiotics actually prevented the gut from returning to its previous, healthy state.
“This was worse than not doing anything. It was significantly bad and persistent,” Professor Eran Elinav, the lead author for both studies explained. Yikes.
So, what do we make all of this? Should we throw our expensive bottle of probiotics from the health store out the window? Well, not necessarily. The study looked primarily into commercial probiotics—the ones you buy in the supermarket.
“We wanted to determine whether probiotics such as the ones you buy in the supermarket do colonise the digestive tract like they’re supposed to, and then whether these probiotics are having any impact on the human host. Surprisingly, we saw that many healthy volunteers were actually resistant in that the probiotics couldn’t colonise their gastrointestinal (GI tracts),” adds Professor Elinat.
But if the study tells us anything, it’s that there needs to be a move away from a one-size-fits-all approach to probiotics. They aren’t all created equal in terms of quality, and not everyone needs to be taking probiotics. In the future, we’re likely to see a more personalised approach to probiotics, where they are tailored to an individual’s needs. In the meantime, it’s worth chatting to your GP or naturopath before you invest in a pricey bottle of probiotics.