Written by Joyce Smith, BS. This post hoc analysis revealed that an eight-week supplementation with B. longum and L. helveticus in depressive patients improved depression symptoms, possibly by increasing BDNF levels.
Psychobiotics refer to probiotics (or prebiotics that support probiotics) that when ingested in adequate amounts, have been shown to positively influence mental health 1,2. Their impact on mental health is through the microbiota-gut-brain axis (MGBA), a two-way highway of communication between the central nervous system (CNS) and the gut microbiota. Studies have shown that alterations in gut microbial composition, or weakening of the tight junction barrier and increased intestinal permeability and inflammation can, via the MGBA, have a modulatory effect on brain chemistry. Supplementation with psychobiotics can positively influence mental health by modulating circulating cytokines, chemokines, neurotransmitters, or brain-derived neurotrophin factor (BDNF) levels via the MGBA. 2 BDNF, as a neurotrophin, regulates neurogenesis by promoting cell growth, proliferation, migration, differentiation, and death.
Researchers have recently shown that a psychobiotic combination of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175; CEREBIOME significantly improved anxiety and depression symptoms in patients with depression 3. Psychobiotics, in recent animal studies, have also shown improved stress and anxiety in rats 3 and depression in mice 4 suggesting that the gut microbiota increased BDNF levels in the brain hypothalamus 5. However, the role of psychobiotics on depression in humans has to date not been characterized, which led researchers to do the following exploratory post hoc analysis of a double-blind, randomized placebo-controlled trial 6. The purpose of the analysis was to glean additional knowledge into the potential mechanisms of action of psychobiotics, particularly with respect to the beneficial effects of a psychobiotic formulation containing L. helveticus R0052 and B. longum R0175 on depressed patients and to assess changes in serum BDNF levels.
In the original trial, 110 patients were randomized to receive either a probiotic combination, a prebiotic or a placebo of which 78 patients were included in the post hoc analysis. For this analysis, 28 patients received probiotic; 25 received prebiotic and 25 received placebo. Serum BDNF levels of participants were measured at baseline and endpoint. Becks Depression Inventory (BDI) scores were determined and a correlation between depression severity and BDNF levels was assessed for the three interventions.
After 8 weeks of supplementation, BDNF levels differed significantly between the probiotic, prebiotic and placebo groups (P < 0.001). Furthermore, BDNF levels in the probiotic group were significantly higher than in both the prebiotic (P < 0.001) and placebo groups (P = 0.021). In the prebiotic group, BDNF levels were reduced but not significantly compared to the placebo group (P > 0.05), while the BDNF levels of the probiotic group were inversely correlated with depression severity compared to placebo P < 0.001). These findings were consistent with previous studies that evaluated the effects of probiotics on BDNF levels in animal models (22). BDI score changes over the 8 weeks were also inversely correlated and were significantly reduced in the probiotic group compared to placebo group; however, were not different in the prebiotic group. The authors suggested that fermentation of the probiotics used in this post hoc analysis may interact with enteric neurons to regulate the enteric nervous system excitability, and affect the CNS via vagal pathways. They recommend future clinical trials to confirm the potential benefits of other probiotics and prebiotics on BDNF levels and depression in psychiatric populations.
An important study limitation was the failure to address intestinal microbiota composition or sex hormones in the study participants which could possibly cause interactions.
Source: Heidarzadeh-Rad, Nazanin, Hülya Gökmen-Özel, Asma Kazemi, Negin Almasi, and Kurosh Djafarian. “Effects of a Psychobiotic Supplement on Serum Brain-derived Neurotrophic Factor Levels in Depressive Patients: A Post Hoc Analysis of a Randomized Clinical Trial.” Journal of neurogastroenterology and motility 26, no. 4 (2020): 486.
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Posted November 9, 2020.
Joyce Smith, BS, is a degreed laboratory technologist. She received her bachelor of arts with a major in Chemistry and a minor in Biology from the University of Saskatchewan and her internship through the University of Saskatchewan College of Medicine and the Royal University Hospital in Saskatoon, Saskatchewan. She currently resides in Bloomingdale, IL.
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- Arseneault-Bréard J, Rondeau I, Gilbert K, et al. Combination of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 reduces post-myocardial infarction depression symptoms and restores intestinal permeability in a rat model. Br J Nutr. 2012;107(12):1793-1799.
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- Heidarzadeh-Rad N, Gökmen-Özel H, Kazemi A, Almasi N, Djafarian K. Effects of a Psychobiotic Supplement on Serum Brain-derived Neurotrophic Factor Levels in Depressive Patients: A Post Hoc Analysis of a Randomized Clinical Trial. J Neurogastroenterol Motil. 2020;26(4):486-495.
