It might be time to load up on the kombucha — because, apparently, it could put you in a better mood.
In a new study from the Leiden Institute of Brain and Cognition, psychologists Laura Steenbergen and Lorenza Colzato found that people spend less time dwelling on bad feelings and experiences from the past after drinking probiotics for four weeks.
Probiotics are live bacteria and yeasts that are improve your digestive health and immune function. While bacteria commonly has a negative stigma, probiotics are considered "good" bacteria, because they help promote gut health. These researchers set out to find out if these microorganisms have any impact on mental health, too.
Their focus? Rumination.
"Rumination is one of the most predictive vulnerability markers of depression," said Steenbergen in a press release. "Persistent ruminative thoughts often precede and predict episodes of depression."
The randomized trial included 40 healthy young adults without mood disorders. Half took a powdered probiotic supplement either mixed with milk or water and the other half received a placebo powder. Both groups thought they were getting the probiotic and drank their concoction nightly for four weeks.
Twice, the subjects were asked to fill out a questionnaire that determines sensitivity to depression: once before the four weeks and once after they were over. Using this survey, the researchers could figure out how likely a subject was to convert a sad thought to a lingering depressive episode.
There was no difference between the two groups before the intervention began, but after four weeks, those who took the probiotic reported significantly less ruminative thoughts than the control group. In other words, when the probiotic-takers were in a sad mood, they had fewer persistent distressing thoughts than the placebo-takers.
Keep in mind, though, that the study is preliminary and could not yet identify the mechanisms by which probiotics could improve mood. Plus, they didn't take into account what kinds of foods the subjects were ingesting — like probiotic-rich foods like kefir and kimchi —throughout the four weeks.
Regardless, "these results provide the first evidence that the intake of probiotics may help reduce negative thoughts associated with sad mood," said Colzato. "As such, our findings shed an interesting new light on the potential of probiotics to serve as adjuvant or preventive therapy for depression."
So, continue eating your daily Greek yogurt (or pickle, like me) to keep your gut happy, and who knows, you could also be keeping your mind healthy, too.