• A recent clinical trial suggests that probiotics could help improve negative moods.

  • New research supports the idea that the gut-brain axis is important for emotional regulation.

  • However, professionals advise that probiotics should not replace traditional psychiatric treatments.

A recent clinical trial has found that probiotics can lessen negative moods, bolstering evidence that the gut-brain link is key to mental health.

In this randomized, double-blind, placebo-controlled trial, it was observed that improvements in mood could be seen in participants as soon as two weeks after starting probiotic supplementation.

This study included healthy adults, suggesting that probiotics might be beneficial for mental wellness broadly, not just for those with clinical depression.

The findings were detailed in the April 9 issue of the journal npj Mental Health Research.

The researchers pointed out that daily mood tracking helped identify subtle mood improvements that might be overlooked by other mental health evaluations.

Katerina Johnson, PhD, the study’s lead author from the University of Oxford, UK, explained to Healthline, “This is the inaugural study using daily mood monitoring to gauge the impact of probiotics. Remarkably, by study’s end after a month, participants’ mood continued to enhance,”

The study contributes to the growing interest in the gut-brain connection, which is thought to significantly influence our emotions and mood through complex interactions.

The gut is responsible for producing a significant amount of serotonin (about 95%), a neurotransmitter that affects everything from mood to appetite, suggesting that better gut health could be linked to improved mental health.

Enhancement of Mood Through Probiotics

The study involved 88 healthy volunteers, averaging 22 years of age, who were neither overweight nor engaged in heavy alcohol or drug use.

Participants were randomly assigned to either a multispecies probiotic blend or a placebo for a period of 28 days.

The probiotic blend contained nine bacterial strains, including varieties of Bifidobacterium, Lactobacillus, and Lactococcus. Each participant consumed a 2-gram sachet dissolved in lukewarm water daily.

Before and after this four-week period, participants underwent a series of psychological assessments, including tests for anxiety, worry, depression, and negative affect.

While traditional psychological assessments showed minimal difference between the probiotic and placebo groups, daily mood tracking revealed significant mood improvement in the probiotic group starting around the two-week mark.

“Daily monitoring gives us a clearer picture of mood changes over time with probiotic use,” Johnson commented. She further explained that psychological questionnaires often categorize feelings into specific emotions, which might miss overall mood improvements.

This suggests that probiotics may be beneficial for mental health even among the general, healthy population, and that conventional research methods might not capture these benefits. Interestingly, the improvements were specific to negative mood, with positive mood remaining stable in both groups.

Lisa Durette, MD, from the University of Nevada Las Vegas, who was not involved in the study, noted the importance of exploring alternative mental health treatments. “Many patients report feeling emotionally muted by antidepressants, a side effect not observed with probiotic use,” she said.

The study also indicated that individuals with a higher baseline risk aversion seemed to benefit the most from probiotic use in terms of mood improvement.

Probiotics as a Complement, Not a Replacement for Mental Health Care

Despite the encouraging findings, experts emphasize that probiotics should not replace established psychiatric medications or therapies.

While probiotics may enhance mental health strategies, they are not adequate as stand-alone treatments for mental disorders.

Christoph Thaiss, PhD, a pathology professor at Stanford University who did not participate in the research, remarked, “It’s crucial to remember that probiotics are dietary supplements and do not undergo the rigorous efficacy testing that FDA-approved medications do.”

He added that probiotics could still play a supportive role in managing mood disorders clinically.

Durette also highlighted the importance of holistic approaches, including diet and exercise, in mental health treatment, advising patients to be well-informed about the benefits and risks of supplements like probiotics.

However, Durette acknowledged the need for further research to determine the appropriateness of these interventions as substitutes for traditional treatments.