Exploring the Role and Potential of Probiotics in the Field of Mental Health: Major Depressive Disorder

Abstract

The field of probiotic has been exponentially expanding over the recent decades with a more therapeutic-centered research. Probiotics mediated microbiota modulation within the microbiota–gut–brain axis (MGBA) have been proven to be beneficial in various health domains through pre-clinical and clinical studies. In the context of mental health, although probiotic research is still in its infancy stage, the promising role and potential of probiotics in various mental disorders demonstrated via in-vivo and in-vitro studies have laid a strong foundation for translating preclinical models to humans. The exploration of the therapeutic role and potential of probiotics in major depressive disorder (MDD) is an extremely noteworthy field of research. The possible etio-pathological mechanisms of depression involving inflammation, neurotransmitters, the hypothalamic–pituitary–adrenal (HPA) axis and epigenetic mechanisms potentially benefit from probiotic intervention. Probiotics, both as an adjunct to antidepressants or a stand-alone intervention, have a beneficial role and potential in mitigating anti-depressive effects, and confers some advantages compared to conventional treatments of depression using anti-depressants.

Psychological Symptoms in COVID-19 Patients: Insights into Pathophysiology and Risk Factors of Long COVID-19

“…Probiotics are one of the potential adjunctive treatments for psychiatric sequelae among COVID-19 survivors, other than the conventional use of psychotropic medications. Within the last decade, numerous research and clinical trials have been conducted to determine the effects of probiotics on mental health, and clinical trials have proven efficacy for improving mental illness [ 165 ]. A systematic review and meta-analysis have shown that probiotic administration was associated with lower depression and anxiety, relative to the placebo group at the end of treatment [ 166 ].…”

“…Thus, probiotics come into place in this context, as they have anti-inflammatory, antipathogenic, and antimicrobial properties, which aids the restoration and maintenance of intestinal homeostasis and microbial balance. They mediate its anti-inflammatory effects by modulating pro-inflammatory cytokines, regulating IDO activity, and restoring intestinal barrier function [ 165 ] ( Figure 2 ). A recent meta-analysis revealed that probiotic intervention can significantly reduce the expression of IDO, an important enzyme which metabolizes tryptophan to kynurenine, in the immune cells and plasma of patients across several clinical trials [ 174 ].…”

Cortical and Subcortical Brain Volumes Partially Mediate the Association between Dietary Composition and Behavioral Disinhibition: A UK Biobank Study

“…Specifically, several known causal pathways exist through which diet can influence brain functioning. For instance, intake of healthy foods is known to decrease inflammation markers and thereby decrease neuroinflammation [ 51 , 52 ]. Similarly, HPA-axis activation is shown to be downregulated through decreased pro-inflammatory cytokines and glucocorticoid levels in response to dietary alterations.…”

Nutrition and Cancer Risk from the Viewpoint of the Intestinal Microbiome

“…Examples of probiotics include supplements such as yogurt, natto, miso, lactic acid bacteria, and bifidobacteria. They are often used in diseases, such as infectious diarrhea (travelers' diarrhea), antibioticassociated diarrhea, Helicobacter pylori infection, constipation, irritable bowel syndrome, hepatic encephalopathy, Crohn's disease, and ulcerative colitis [86][87][88][89].…”