Psychobiotics are a class of probiotics (live bacteria) that confer a mental health benefit. The gut is often referred to as the “2nd brain” and houses 90% of your body’s serotonin – the “feel good” hormone. As the link between the gut and the brain becomes more evident, utilizing psychobiotics to improve mental health will likely continue to gain traction.
Your brain and gut microbes are intimately linked – the microbes in your gut produce neurotransmitters (dopamine, norepinephrine, serotonin, GABA, etc.) and metabolites like short chain fatty acids (SCFAs) that are key to optimal brain function and maintaining the integrity of the blood-brain barrier – the lining of tightly packed cells that filters and blocks harmful substances from entering your brain. Gut microbiome imbalance (known as dysbiosis) affects the communication between the two organs and is linked to mental health disorders like anxiety and depression.
An estimated 20% of Americans suffer from a mental health condition, so mental health therapeutics is a really important field. Studies show that a psychobiotic diet – high in dietary fiber and fermented foods – is linked to improved gut bacteria balance and can positively impact mental health conditions, including perceived stress, depression, and anxiety. These findings have led to more pill-focused investigations – if a diet high in pre- and probiotic foods can improve mental health, can a pill do the same?
A 2024 article published in Nutrients reviewed multiple studies from 2000 to 2023 that looked at psychobiotic pills for the treatment of cognitive and psychiatric disorders. Out of 51 studies and over 3,000 patients, researchers found that psychobiotics may have a “high measure of effectiveness” and are most effective in treating depressive symptoms in older females. Unfortunately, due to the wide range of demographics, varying treatment timeframes (from 4 to 24 weeks) and different types of probiotics (Lactobacillus and Bifidobacteria strains were most effective), the study’s ability to validate specific psychobiotic treatment protocols for improving mental health is limited.
A 2019 study looked at 10 clinical trials where psychobiotics were used to treat anxiety and depression. Findings showed that while probiotics reduced depressive symptoms, there was no reduction of symptoms in those with anxiety or acute stress. Other studies have used probiotics alongside psychotherapy and found positive results.
While research shows some improvements in mental health symptoms with psychobiotics (mostly in depressive symptoms), scientists stress the importance of a multi-faceted approach to improving mental health, including proper nutrition (like the microbiome-enhancing diet in The Microbiome Solution) exercise, stress reduction, and psychotherapy. If you choose to supplement with a probiotic pill, keep in mind that high potency probiotic pills are not currently indicated for the treatment of mental health disorders, and more research is needed to solidify probiotics as an effective tool in treating psychological conditions.
Finally, if you decide to incorporate probiotic pills as a tool in your mental health box, remember your pill is only as powerful as the diet you feed it; helpful bacteria will not take root and multiply without providing them with the whole food plant fiber they thrive on (prebiotic foods).
For more information on this topic, check out these Gutbliss resources:
- Episode #16 from The Gutbliss Podcast, Gut-Brain: The Second Brain in Your Gut
- Episode #25 from The Gutbliss Podcast, The Future of Probiotics: Viral Illnesses, Psychobiotics, and More
- From The Gutbliss Blog, Diet impacts depressive symptoms in young adults
- From The Gutbliss Blog, Microbial change improves anxiety, not with probiotics
- From Dr. Chutkan’s Office Hours series, Cognitive Decline & the Gut
