Psychobiotics to tackle mild MDD, study suggests moving from pharma to probiotic strains

13 Mar 2023 --- Probiotic strains such as Lactobacillus and Bifidobacterium can interact with major depressive disorder (MDD) and may hold the potential to complement or replace pharmaceutical care for depression, depending on its severity. This is according to a new study published in Nature.

The authors demonstrate that prior research has shown gut dysbiosis – an imbalance of gut bacteria – is often present in people struggling with depression. Usually, gut dysbiosis in depressed people includes a lack of microbial diversity and an inversely proportional abundance of pathobionts to beneficial microbiota compared to those not depressed.

The concept of psychobiotics follows a microbiota-targeting diet, making probiotics a “traditional psychobiotic agent that exerts pronounced anti-depressive effects similarly” as it modulates gut-brain communication, increasing mental health well-being.

Restoring balance
The authors note that the role of probiotics for depression is to restore the gut microbial balance by modulating the microbiota. Most of the results are based on preclinical studies carried out on mice or rats, which the authors argue is similar to the gut microbiome of humans. 

Based on the study’s results, probiotics can potentially treat MDD.Based on its literature review, probiotics can potentially treat MDD. However, “seeking to validate probiotics usage for this indication will be challenging and elusive, considering the inherently ambiguous nature of this enigmatic branch of medicine and the scarcity of probiotic studies in clinical depression,” says the study.

The authors also say that probiotics are worth considering for clinical depression as a treatment in combination with general treatments. For those patients with mild MDD, stand-alone treatments are suggested as there might not be a need for pharmacological intervention.

Furthermore, probiotics might work as a preventative treatment for those developing MDD.

“It seems only fitting that scientists and industrialists are considering developing probiotic strains that effectively ameliorate depression by tackling different neurobiological and genetic bases of this disorder,” states the study. 

“The presented probiotic strains could be utilized as starter strains for industrial development and manufacturing of meta biotics to address the gap in determining the selection of target novel probiotics.”

A double-edged sword
The authors argue that the human gut is exposed to various pathogenic and commensal microorganisms as “a double-edged sword.”

Further elaborating that as long as the intestinal immune system can discriminate between beneficial and pathogenic activities of microbes and bring out the appropriate response, “the human host will continue to reap the positive physiological outcomes of this cross-talk between the gut microbes and the immune system.”

“However, if the gut microbial balance is disturbed, homeostatic regulation will be severely affected, leading to the manifestation of immune responses,” notes the study.

Highlighted foods with psychobiotic effects are high-fiber fruits and vegetables, whole grains, legumes and fermented foods.Foods with psychobiotic effects are high-fiber fruits and vegetables, whole grains, legumes and fermented foods.

When fermenting dietary fibers, microbial metabolites are produced, which play a role in the modulation of neurotrophic factors and neurotransmitters, inflammation, gut barrier functions and neuronal transcription, detail the authors.

Mental health
Another recent study published in the Journal of Affective Disorders found that probiotics contributed to structural and functional changes, which decreased depressive symptoms in people consuming probiotics compared to those who did not.

NutritionInsight covered a study from June last year on the increased interest and investments in psychobiotics to become an alternative to antidepressants. 

With recent attention to the gut-brain axis, industry members argue that the gut is connected to more than such. AB Biotics previously told us about other health aspects linked to the gut, such as the gut-eye, gut-immunity and gut-skin axes.

Edited by Beatrice Wihlander