It’s become increasingly clear that there’s much more to our guts than the simple breakdown and digestion of food.
In recent years, studies have repeatedly shown that:
- An unhealthy gut microbiome is a threat to the aging process.
- On the contrary, a healthy gut can actually make it easier to work through post-traumatic stress disorder (PTSD).
- In fact, it’s linked to multiple mental health disorders, from ADHD to schizophrenia.
Now, a new paper just published in npj Mental Health Research argues that – at least in healthy adults – probiotics can fight back against negative feelings.
“The gut–brain connection provides various routes through which bacteria in the gut can influence how we feel and behave, including via the vagus nerve, immune system and hormones,” co-author and Research Associate in Oxford University’s Experimental Psychology Department Katerina Johnson, PhD, said.
The study offers up some new information about how probiotics might influence our mental health.
“We found that various traits, most notably a propensity for risk avoidance, were associated with a greater effect of probiotics on mood,” Johnson added.
Methodology
The researchers recruited 88 healthy young adults. They relied on a randomized, double-blind, placebo-controlled design to explore how a multispecies probiotic might influence emotion regulation and mood. Throughout the four-week study, participants ran through a battery of assessments. They included psychological questionnaires, emotional processing tasks, and daily mood ratings.
The standard psychological questionnaires revealed almost no change in participants’ emotional states after the probiotic intervention. But the daily mood tracking offered up a revelation. The researchers noticed a clear and consistent drop in negative mood in those taking probiotics. It was a trend the authors first noticed about halfway through the study.
“It is striking that by simply asking participants how they were feeling each day, we could detect the beneficial effects of probiotics on mood,” co-author and Leiden University assistant professor Laura Steenbergen, PhD, remarked. “In contrast, the standard psychological questionnaires that are common in this field were not sensitive enough to pick up these changes.”
Larger Implications of Probiotics
The research underscores the growing importance of methodological design in evaluating mental health interventions. Traditional tools, such as symptom questionnaires, while valid, might miss some of the more nuanced changes in one’s emotional experience. This particular study’s use of daily mood ratings, for example, provided a high-resolution view of the participants’ emotional trajectories.
The implications could be huge. As public interest in gut health accelerates and mood disorders rise worldwide, more people recognize probiotics as a potential tool for supporting mental well-being.
Interestingly, the researchers also identified psychological traits that predicted who benefited the most. Participants who scored higher in risk aversion — a trait linked to vulnerability to depression — were more likely to experience a reduction in negative mood. This suggests probiotics might offer the greatest benefit as an early intervention strategy.
Though probiotics didn’t make much of a difference in cognitive tasks, the authors noticed signs that they might boost emotional awareness. In one example, the authors discussed how the probiotic group showed slight improvements in accurately recognizing facial expressions, hinting at a possible bump in emotional processing.
Notably, the timeline parallels that of traditional antidepressants, which typically take about two weeks to start curbing symptoms. While probiotics and antidepressants operate differently, the researchers point out that both might influence mood via anti-inflammatory effects and neural pathways.
Digging Deeper
Finally, the authors suggest that probiotics might offer a subtle but meaningful mental health benefit for the general population. Specifically, this study opens the door to targeted probiotic use. It suggests probiotics could serve as a mental health support strategy. This approach might help stave off the onset of more serious conditions.
“Perhaps in the future probiotics could be used in a targeted way as an early intervention to reduce the chances of negative feelings progressing to mental health conditions such as depression, though more research would be needed to confirm that,” Steenbergen suggested.
Further Reading
The Road Between The Gut And Schizophrenia Runs Both Ways
