Popular gut probiotic completely craps out in randomized controlled trial

Any striking marketing claims in companies' ads about the gut benefits of a popular probiotic may be full of, well, the same thing that has their target audience backed up.

In a randomized controlled trial, the probiotic Bifidobacterium animalis subsp. lactis—used in many probiotic products, including Dannon's Activia yogurts—did nothing to improve bowel health in people with constipation, according to data from a randomized triple-blind placebo-controlled clinical trial published Wednesday in JAMA Network Open.

The study adds to a mixed and mostly unconvincing body of scientific literature on the bowel benefits of the bacterium, substrains of which are sometimes sold with faux scientific-sounding names in products. Dannon, for instance, previously marketed its substrain, DN-173 010, as "Bifidus regularis."

For the new study, researchers in China recruited 228 middle-aged adults, 85 percent of whom were women. The participants, all from Shanghai, were considered healthy based on medical testing and records, except for reporting functional constipation. This is a condition defined by having two or more signs of difficulty evacuating the bowels, such as frequent straining and having rock-like stool. For the study, the researchers included the additional criterion that participants have three or fewer complete, spontaneous bowel movements (CSBMs) per week.

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