The Gut-Brain Connection

How do Bacillus spores support mental health?

The term “gut-brain axis” refers to the bidirectional communication between the gut and the brain. Gut bacteria play an essential role in this system due to their ability to support neurotransmitters, hormones, and neuropeptides production. These compounds are able to cross-talk with the brain in direct and indirect ways.[1]  

Research has shown that gut bacteria can influence the brain, and may impact sleep, trigger food cravings and feelings of low mood among other things. Fascinating discoveries in the world of probiotics and gut health have revealed that the use of bacillus spores can offer positive results for those experiencing mood-related conditions[2]

The connection between low mood and Bacillus spores

Healthy gut bacteria help support the regulation of cytokine activity, brain function, nerve health, appetite and more. Bacillus spore supplementation is a novel strategy to support a healthy mood. While many Bacillus strains can support short-chain fatty acid (SCFAs) production, they can also support the growth of other commensal gut populations that have health supporting capabilities. In addition, they support a healthy gut barrier and brain – which, as we are finding out, are connected via the gut-brain axis. Bacillus spores appear to be an effective, and more natural approach for mood and sleep issues. 

Bacillus coagulans is associated with a  healthy mood and digestion. This is interesting because some digestive issues are associated with having a high risk for low mood! Spore-forming bacteria like B.coagulans supports SCFA production. Did you know that SCFA’s are amongst some of the most important postbiotics currently known? Postbiotics are the metabolic by-products of healthy flora that support the gut and the entire body; these compounds can be prebiotic, immune supportive and hormonally active[3]

Additionally, Bacillus subtilis supports serotonin synthesis by supporting the production of the amino acid precursor tryptophan[4]. Tryptophan levels in the gut are correlated with serotonin levels in the brain. Serotonin is not just a mood hormone, it plays a role in gut motility, cardiovascular health, and sexual function. By supporting serotonin activity, all of these areas inside and outside of the brain may also be supported. 

Bacillus indicus, HU36™, a carotenoid-rich probiotic, naturally produces forms of lycopene, astaxanthin, zeaxanthin, beta-carotene and lutein in the digestive tract right at the site of absorption. These carotenoids are more bio-accessible and bioavailable (about 4.5 times as high!) than beta-carotene[5]. This is exciting because it is now becoming more well known that what we eat can impact our mood – and specifically, antioxidants can have a positive impact on low mood[6]

An essential part of any healthy mood toolkit

Mood-supporting supplements are increasing popular as modern lifestyles become more demanding and stressful. Although probiotics are a recent entry to the mood supplement category, their entry is supported by science[7]. Research demonstrating the gut-brain connection, an increase in consumer awareness around probiotics, and science demonstrating the efficacy of spore-based probiotics in particular, make spore-based probiotics an essential companion to other mood supplements. 


[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] Wegh CAM, Geerlings SY, Knol J, Roeselers G, Belzer C. Postbiotics and Their Potential Applications in Early Life Nutrition and Beyond. Int J Mol Sci. 2019;20(19):4673. Published 2019 Sep 20. doi:10.3390/ijms20194673 

[4] Bjerre K, Cantor MD, Nørgaard JV, Poulsen HD, Blaabjerg K, Canibe N, Jensen BB, Stuer-Lauridsen B, Nielsen B, Derkx PM. Development of Bacillus subtilis mutants to produce tryptophan in pigs. Biotechnol Lett. 2017 Feb;39(2):289-295. doi: 10.1007/s10529-016-2245-6. 


[6] Huang Q, Liu H, Suzuki K, Ma S, Liu C. Linking What We Eat to Our Mood: A Review of Diet, Dietary Antioxidants, and Depression. Antioxidants (Basel). 2019 Sep 5;8(9):376. doi: 10.3390/antiox8090376. PMID: 31491962; PMCID: PMC6769512. 

[7] Marotta A, Sarno E, Del Casale A, et al. Effects of Probiotics on Cognitive Reactivity, Mood, and Sleep Quality. Front Psychiatry. 2019;10:164. Published 2019 Mar 27. doi:10.3389/fpsyt.2019.00164 

By Jessica Sanders, Gutsi® Naturopath.