Probiotics & The Immune System

Probiotics are defined by the World Health Organization as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host”

Changes in the gut microbiome can have a therapeutic response which has led to the use of probiotics in traditional medicine since long before probiotics were identified and acknowledged as the mechanism of this response. As the use of probiotics grows, so to does the body of knowledge we have about the relationship between the microorganisms that inhabit our gut and our overall health. We are now able to realize the delicacy of our gut’s environment. Negative changes to the gut microbiome result in altered activity of neurotransmitter systems & immune function which can be potentially detrimental and contribute to a number of disorders or conditions. Similarly, targeted positive changes to the gut microbiome may reduce the symptoms of and possibly even reverse certain conditions.

 Links have been made between gut health and depression, anxiety, stress, even sleep. A recent study tested this relationship in mice, which provide a very useful model of our own digestive and nervous system. The study found that treatment with a lactic acid producing strain of probiotic may help to reduce stress as well as depression and anxiety. The lactic acid producing bacteria “induced region-dependent alterations in GABAB1b mRNA in the brain with increases in cortical regions (cingulate and prelimbic) and concomitant reductions in expression in the hippocampus, amygdala, and locus coeruleus, in comparison with control-fed mice” and more importantly, “reduced stress-induced corticosterone and anxiety- and depression-related behavior” (Bravo, 2011).

Ongoing research is investigating whether gut bacteria are one reason for the mood symptoms in medical conditions


A growing body of evidence suggests that probiotics play an important role in maintaining the function of the immune system. Additionally, researchers are finding that the microorganisms in our gut profoundly impact immunity in humans (and other mammals).

The GI tract’s intestinal mucosa functions as a barrier against antigens.
Probiotics re-balance gut flora to bolster immune defenses.

In various studies probiotics have been found to reduce the number of respiratory tract infections, the average length of illness, need for antibiotics, & work absences.

What are the benefits of probiotics?

Regular use of probiotics can help reduce the risk of developing cold & flu, and reduce the duration and severity of cold & flu if you do get sick.

Bacillus Coagulans is a novel lactic-acid producing probiotic which studies have found to be beneficial for its ability to:

  • promote intestinal digestion
  • produce enzymes to facilitate excretion and digestion
  • regulate host symbiotic microbiota and inhibit the growth of pathogenic bacteria
  • normalize immune cell functions

“Compared with traditional commercial probiotics, B. coagulans is more likely to exert its probiotic role in the intestinal tract than traditional live probiotics due to its ability to produce spores. B. coagulans can survive from the stomach in the form of spores and germinate in the intestine, thereby exerting its probiotic effect.”

Studies have confirmed that B. coagulans is able to normalize the amount of immune system cells (the number of lymphocytes, macrophages, and T-cells) as well as those cells’ ability to promote immune system function (Bomko, Nosalskaya, Kabluchko, Lisnyak, & Martynov, 2017).

Daily oral consumption of Bacillus Coagulans in capsule form “significantly increased T-cell production” in response to viruses (Baron, 2009). “[B. coagulans] probiotic may be a safe and effective therapeutic option for enhancing T-cell response to certain viral respiratory tract infections”.


Hooper, L. V., Littman, D. R., & Macpherson, A. J. (2012). Interactions between the microbiota and the immune system. Science (New York, N.Y.), 336(6086), 1268–1273.

Baron M. (2009). A patented strain of Bacillus coagulans increased immune response to viral challenge. Postgraduate medicine, 121(2), 114–118.

Bomko, T. V., Nosalskaya, T. N., Kabluchko, T. V., Lisnyak, Y. V., & Martynov, A. V. (2017). Immunotropic aspect of the Bacillus coagulans probiotic action. The Journal of pharmacy and pharmacology, 69(8), 1033–1040.