The Enteric Nervous System (ENS) is the second brain of your body. But instead of controlling and regulating your entire body, the ENS is in charge of your gut. Like the brain, it also contains neurons. Specialised cells that do the work of receiving and utilising information received from the gut microbiome and the brain to regulate gut health. Specifically, the ENS is responsible for regulating the movement and function of YOUR digestive system. Individuals whose gut microbes are unhealthy often suffer from reduced movement and functioning of the digestive system. Although probiotics may improve constipation for some, how exactly they work, and the difference between food-based probiotics and supplementation, is unknown. This study focused on the if and how a common probiotic, Lactobacillus rhamnosus GG (LGG), improves the functioning of the ENS in mice.

Type of study

This study gave conventional mice and germ-free mice with a common probiotic supplement, Lactobacillus rhamnosus GG (LGG), along with other non-probiotic strains. Here ‘conventional mice’ means that the mice were raised in a standard way. Exposed to bacteria and inhabited by a healthy, diverse microbiome. Germ-free means that the mice were raised without any exposure to bacteria, therefore completely lacking microbes.


Study Findings

In mice given the probiotic supplement for 1 to 2 weeks, researchers observed changes to the neuron (nerve cells) populations in the ENS and improved functioning of the digestive system. Moreover, when the LGG probiotic was taken daily for two weeks, researchers found improved overall digestive system functioning. As well as increased stool frequency in both conventional and germ-free mice groups.

Together this study indicates that daily consumption of this specific probiotic supplement (in mice at least) does cause change. It may influence both the structure and function of the ENS but before we can jump to conclusions in humans, we need more research.


Study Limitations

Since this study was done on mice rather than humans, we cannot directly translate these results to humans. Regardless, these studies are a good proxy measure. As it can be tough to tightly control studies done with humans in the same way that we can in mice.



The bottom line? It seems that consumption of certain probiotics may directly impact how the enteric nervous system of mice operates.  Which in turn controls their digestive system. Although these results are promising, we need to further explore the link between probiotics and ENS functioning in humans.


About the author

Hana is a Senior at the Minerva Schools at KGI, studying cells and organisms, an interdisciplinary major combining biology, chemistry, and bioengineering and minoring in data science. She is interested in science communication, gut health, and neuroscience.


Qin, Y., & Wade, P. A. (2018). Crosstalk between the microbiome and epigenome: messages from bugs. The
Journal of Biochemistry, 163(2), 105–112. Retrieved from