Will Probiotics Ever Live Up to the Hype?

Changing your microbiome takes more than just swallowing a pill full of bacteria.

A bucket of glass bottles of kombucha over ice
Tibrina Hobson / Getty

“Altering someone’s microbiome is as complicated as changing a rainforest or a coral reef,” The Atlantic’s Ed Yong told an audience at the National Institutes of Health on Tuesday. “It’s not easy.”

In conversation with Francis Collins, the director of the NIH, Yong discussed the future of microbial medicine. He argued that doctors should focus on an “ecological type of thinking” instead of the more simplistic approach behind “medically underwhelming” probiotic treatments. “It’s not just thinking of microbes as a pill that you could give to someone to fix a lack of something,” Yong said.

One recent study that Yong praised for taking a “careful” and “clever” approach to probiotics involved preventatively treating newborns in India with a carefully selected cocktail of bacteria along with sugar to help the microbes colonize their new environment in the infants’ guts. That two-pronged approach—called a synbiotic—was extremely successful. Rates of sepsis among the babies after just a week of daily doses were 40 percent lower than in the control group. Yong called the trial “an important step in the right direction.”

Probiotics that are less attentively designed, Yong said, are likely to have little effect on the balance of bacterial strains living in your gut. “Taking probiotics,” he said, “is a little bit like raising a small number of captive, zoo-born animals and then releasing them into the jungle and hoping that they’ll do well.” For this reason, as Yong has written in his recent book, I Contain Multitudes, haphazard probiotic treatments are like a breeze blowing between two open windows: “It might rattle some objects,” but the introduced bacteria won’t stick around long enough, or in high enough numbers, to make much of a difference.

To see robust effects in randomized, controlled studies, researchers may have to invest more thought and resources into treatments that give bacteria some of the tools they need to survive, like the one in the Indian study, or into personalized probiotics. As Yong told the audience at the NIH, “the arithmetic around microbial medicine is not going to be that simple.”

Watch the full interview below: