The Gut brain connection – Bacillus Spores for mental health

The Gut Brain connection –  Bacillus Spore Supplements and Mental Health

The gut-brain axis was first discovered in the 1960’s, but it wasn’t until decades later that this system was further explored for its ability to alleviate mood disorders.1 The term “gut-brain axis” refers to the bidirectional communication between the gut and the brain. Gut bacteria play essential roles in this system due to their ability to produce neurotransmitters, neurohormones, and neuropeptides. Microbe derived factors can affect the brain by traveling through the blood stream and across the blood brain barrier, effecting the brain directly; stimulating the release of gut hormones that help regulate appetite; causing cytokine production; or by activating the vagal nerve, which connects dendritic cells of the gut to the brain stem. Fascinating discoveries in the world of probiotics and gut health have revealed that the use of probiotic bacillus spore supplements offer positive results for those suffering from mental health conditions. 

A recent randomized, double-blind study found that Bacillus coagulans spore supplementation provided significant symptom relief for those suffering from major depressive disorder (MDD).2 In this study, researchers recruited 40 MDD patients and randomly divided them into either a control group or an experiment group. The experiment group received one tablet of B. coagulans per day for 90 days. Results indicated that the treatment group experienced a significant decrease in clinical symptoms of depression, and improved quality of life and quality of sleep.2 Researchers speculate that these positive results may be due to the short-chain fatty acid (SCFA) production of B. coagulans and other similar spore forming bacillus strains.2 SCFAs have potent anti-inflammatory and anti-microbial abilities, which contribute many beneficial effects to the host.

Bacillus subtilis has been studied in pigs for its ability to produce the serotonin precursor known as tryptophan.3 Gut microbe derived tryptophan is directly correlated to serotonin production in the brain, since it can pass the blood-brain barrier. Serotonin is known as a happy molecule, which reduces aggression.4 Results of a recent animal study involving chicken confirmed that the use of B. subtilis spore supplementation reduces aggressive behavior in hens and increases serotonin levels. Researchers highlight that although this is not a human clinical trial, the outcome is promising considering that “neural circuitry for aggression and social behavior appear to be evolutionarily conserved across the vertebrates”.4

Disruptions to the gut barrier are also thought to have negative consequences on mental health. The gut barrier of the large intestine protects the body against the invasion of pathogens and dangerous molecules, such as lipopolysaccharide (LPS). When this protective lining is damaged, due to stress, poor diet, antibiotics, overuse of pharmaceuticals and other factors, LPS can leak into the blood stream. This condition is known as leaky gut syndrome. If LPS crosses the blood-brain barrier, it can injure areas of the brain that effect mood, and cause neuroinflammation. Leaky gut sydrome has recently been proposed as a significant contributor to the onset of depression.5 In fact, recent evidence shows that administration of LPS to mice induces depressive-like symptoms.5 

According to multiple recent studies, administration of Bacillus subtilis, along with a blend of B. subtilis plus B. indicus (HU36), B. coagulans, and B. licheniformis, and Bacillus clausii can repair the gut barrier and significantly reduce levels of LPS leaching into the bloodstream.6,7 In fact, a recent human trial found that 30-day supplementation of a blend of Bacillus spores results diet induced endotoxemia and reduced LPS levels by up to 43%.7

Bacillus spore supplementation is a novel therapeutic strategy to improves mood disorders. While many Bacilllus strains can produce SCFAs and reduce inflammation, they also boost other commensal gut populations that have anti-inflammatory capabilities. In addition, they can heal the gut barrier and reduce total body and brain inflammation. Bacillus spores should be considered a safe, effective and more natural approach for the treatment of depression, anxiety and aggressive behaviors.


1. Holzer P, Farzi A. Neuropeptides and the microbiota-gut-brain axis. Adv Exp Med Biol. 2014;817:195–219. doi:10.1007/978-1-4939-0897-4_9

2. Majeed M, Nagabhushanam K, Arumugam S, Majeed S, Ali F. Bacillus coagulans MTCC 5856 for the management of major depression with irritable bowel syndrome: a randomised, double-blind, placebo controlled, multi-centre, pilot clinical study. Food Nutr Res. 2018;62:10.29219/fnr.v62.1218. Published 2018 Jul 4. doi:10.29219/fnr.v62.1218

3. Bjerre K, Cantor MD, Nørgaard JV, Poulsen HD, Blaabjerg K, Canibe N, et al. Development of Bacillus subtilis mutants to produce tryptophan in pigs. Biotechnology Letters. 2017;39:289-295.

4. Cheng HW, Jiang S, Jiaying H. Gut-Brain Axis: Probiotic, Bacillus subtilis, Prevents Aggression via the Modification of the Central Serotonergic System. InTechOpen. 2019 DOI: 10.5772/intechopen.86775

5. Dang R, et al. Predictable chronic mild stress promotes recovery from LPS-induced depression. Molecular Brain. 2019; 12(42): 1-12.

6. Zhang HL, Li WS, Xu DN, et al. Mucosa-reparing and microbiota-balancing therapeutic effect of Bacillus subtilis alleviates dextrate sulfate sodium-induced ulcerative colitis in mice. Exp Ther Med. 2016;12(4):2554–2562. doi:10.3892/etm.2016.3686

7. McFarlin BK, Henning AL, Bowman EM, Gary MA, Carbajal KM. Oral spore-based probiotic supplementation was associated with reduced incidence of post-prandial dietary endotoxin, triglycerides, and disease risk biomarkers. World J Gastrointest Pathophysiol. 2017;8(3):117–126. doi:10.4291/wjgp.v8.i3.117

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