The Probiotic Bacteria That Could Reverse Depression And Anxiety

The type of bacteria that helps the brain manage stress, anxiety, and depression.

The type of bacteria that helps the brain manage stress, anxiety, and depression.

The probiotic, Lactobacillus, also known as a ‘good bacteria’ can boost the body’s resilience to environmental stress and reduce symptoms of depression and anxiety.

According to a study, the Lactobacillus species exhibits a protective role against stress, warding off anxiety and depression.

Lactobacillus is found in fermented foods such as yogurt, kefir, and cheese, however, probiotic supplements contain much higher concentrations.

Depression and anxiety are two of the most common and troublesome mental illnesses which affects millions of people, yet current treatments are inadequate.

Dr Alban Gaultier, the study’s senior author, said:

“Our discovery illuminates how gut-resident Lactobacillus influences mood disorders, by tuning the immune system.

Our research could pave the way toward discovering much-needed therapeutics for anxiety and depression.”

Human microbiome & mental health

The gut microbiota (gut flora) consists of trillions of microorganisms including viruses, bacteria, and fungi that live in the digestive tract.

The relationship between the gut flora, the immune system, and the brain has encouraged scientists to look for possible therapies to improve mental health and well-being.

Any illness or poor habit such as lack of physical activity, bad diet, drinking, and smoking could harm the microbiome, leading to serious issues such as cancer and mood disorders.

Past studies on probiotics — due to the vast numbers of microorganisms and the microbiome’s complexity — have struggled to determine what specific bacteria independently influence human brain health.

This research focused on several strains of Lactobacillus, such as L. intestinalis and L. murinus, by removing them in mice.

They found that mice lacking the Lactobacillus species behaved in more stressed and anxious ways.

The findings show the importance of probiotic lactobacilli and how their absence could aggravate depression and anxiety.

Dr Andrea Merchak, the study’s first author, said:

“With these results in hand, we have new tools to optimize the development of probiotics, which should speed up discoveries for novel therapies.

Most importantly, we can now explore how maintaining a healthy level of Lactobacillus and/or interferon gamma could be investigated to prevent and treat anxiety and depression.”


The study was published in the journal Brain, Behavior, and Immunity (Merchak et al., 2023).

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