Research Reveals Probiotics Can Help Improve Mood

When most people think about the benefits of probiotics, they typically center around the gut, but these beneficial bacteria do more than that. In fact, probiotics can have a profound impact on mental health, and new research published in 2025 even found that they can help improve mood over time.

More specifically, a study published in npj Mental Health Research revealed that daily probiotic supplementation can significantly reduce negative mood in healthy adults. Conducted by researchers at Leiden University in the Netherlands, the study highlights the potential of probiotics as a natural approach to enhancing emotional well-being and adds to the growing body of evidence suggesting that gut health plays a crucial role in mental well-being.

Study: Probiotics and mood

Researchers conducted a randomized, double-blind, placebo-controlled trial involving 88 healthy volunteers. Participants were divided into two groups: one received a multispecies probiotic supplement containing strains like Lactobacillus and Bifidobacterium, while the other received a placebo.

Over a four-week period, participants completed daily mood assessments, psychological questionnaires and emotional processing tasks. Participants reported their moods daily and completed psychological questionnaires and emotional processing tasks at the beginning and end of the study.

The study found that those taking probiotics reported a noticeable reduction in negative mood, such as feelings of anxiety, stress and fatigue, beginning after two weeks of supplementation. Interestingly, these improvements were detected through daily self-reports rather than standard psychological assessments, suggesting that traditional tools may not capture subtle mood changes effectively.

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The study also found that individuals with risk-averse personality traits benefited more from probiotic supplementation, indicating that personal characteristics may influence the effectiveness of probiotics on mood.

The researchers concluded that probiotics could benefit mental health in the general population and identified traits of individuals who derive the greatest benefit, allowing future targeting of at-risk individuals.

Other benefits of probiotics

Beyond mood improvement, probiotics have been associated with various mental health benefits. They may enhance emotional processing, as evidenced by improved accuracy in recognizing facial expressions among probiotic users.

Additionally, certain probiotic strains have demonstrated potential in alleviating symptoms of neurodegenerative and neurodevelopmental disorders, such as Parkinson’s and Alzheimer’s diseases.

Probiotics also contribute to cognitive function by reducing oxidative stress and inflammation, enhancing neurotransmitter production, and improving the integrity of the blood-brain barrier. These mechanisms collectively support better mental health and cognitive performance.

Beyond mood enhancement, probiotics offer a range of health benefits. They are known to improve digestive health by balancing gut bacteria, which can alleviate symptoms of conditions like irritable bowel syndrome and inflammatory bowel diseases.

Probiotics also support immune function, reduce inflammation, and may positively impact skin health and weight management.

The gut-brain axis, a communication network linking the gastrointestinal tract and the brain, plays a crucial role in these benefits. Probiotics can influence this axis by modulating neurotransmitter production, such as serotonin and GABA, and by affecting the body’s stress response systems.

Incorporating fermented foods, such as yogurt, kefir, kimchi and miso, into the diet can naturally introduce beneficial probiotics, as can taking a probiotic supplement.

More ways to improve mood

While probiotics offer promising benefits, they are most effective when combined with other natural mood-enhancing strategies. Incorporating probiotics and probiotic foods into one’s diet is just one approach to enhancing mood naturally.

Other effective strategies include:

• Regular exercise: Engaging in physical activity releases endorphins, which are natural mood lifters.
• Balanced diet: Consuming a diet rich in fruits, vegetables, whole grains, lean proteins and other mood-boosting foods supports overall mental health. (You should also avoid bad mood foods.)
• Mindfulness and meditation: Practices like meditation, deep breathing and yoga can reduce stress and anxiety and promote emotional balance.
• Adequate sleep: Ensuring sufficient and quality sleep helps regulate mood and stress levels.
• Social connections: Maintaining strong relationships and social interactions can provide emotional support and enhance happiness.

Conclusion

• The study from Leiden University adds to the growing body of evidence suggesting that probiotics can play a role in improving mood and emotional well-being and underscores the potential of probiotics as a natural intervention for reducing negative mood in healthy individuals.
• By incorporating probiotics into a holistic approach that includes exercise, a balanced diet, mindfulness, adequate sleep and social engagement, individuals can take proactive steps toward improved mental well-being.
• While more research is needed to fully understand the mechanisms and long-term effects, incorporating probiotics (either through supplements or fermented foods) alongside other healthy lifestyle practices offers a promising, natural approach to enhancing mental health.
• For individuals seeking to boost their moods and overall well-being, considering probiotics as part of a holistic lifestyle may be beneficial.