For years, we’d drawn a quiet line between what belongs to mental health and what belongs to physical health. But science keeps uncovering just how connected they really are.
Take for example the interconnections between the brain and the gut. Top researchers are now looking more deeply into the body’s interconnected signaling pathways and how they influence brain function and behavior.
We’ve put together an infographic to help break down the complexity of this process, and to illustrate how deeply mental and physical health are integrated.
Have a look.
Click the image to enlarge
It’s a complex conversation
– Adapted in part from the work of Kirsten Tillisch, MD –
The brain, gut, and microbiota communicate back-and-forth constantly through multiple pathways that influence each other.
-BRAIN: Affects mood, cognition, stress response, and behavior.
-NEURAL Signaling: Neural pathways in the brain, gut, and between the two allow them to send messages back and forth and work together.
-ENDOCRINE Signaling: Gut hormones and stress hormones help coordinate communication between the brain and gut.
-IMMUNE Signaling: The gut and its microbes influence immune responses, affecting communication between the gut and brain.
-METABOLIC Signaling: Microbes produce metabolites, which can affect how the gut and brain communicate.
-GUT: The gut contains extensive neural networks, trillions of microbes, and much of the immune system, constantly communicating with the brain. It is impacted by our environment, thoughts, and feelings.
-MICROBIOTA: Trillions of active organisms that live inside of us – including bacteria, fungi, viruses, and protozoa – interact with one another and influence mood and health.
This isn’t one message traveling along one pathway. It’s many conversations happening at once. These pathways influence one another, creating a dynamic, interconnected system that supports both brain and gut health.
(If you’re sharing this infographic, please be sure to include the copyright information. We put a lot of work into creating these resources for you. Thanks!)
If you’d like to print a copy, just use one of these links:
Mayer, E. A., Tillisch, K., & Gupta, A. (2015). Gut/brain axis and the microbiota. The Journal of Clinical Investigation, 125(3), 926–938. https://doi.org/10.1172/JCI76304
Cryan, J. F., O’Riordan, K. J., Cowan, C. S. M., Sandhu, K. V., Bastiaanssen, T. F. S., Boehme, M., Codagnone, M. G., Cussotto, S., Fulling, C., Golubeva, A. V., Guzzetta, K. E., Jaggar, M., Long-Smith, C. M., Lyte, J. M., Martin, J. A., Molinero-Perez, A., Moloney, G., Morelli, E., Morillas, E., … Dinan, T. G. (2019). The microbiota-gut-brain axis. Physiological Reviews, 99(4), 1877–2013.
Morais, L. H., Schreiber, H. L., IV, & Mazmanian, S. K. (2021). The gut microbiota–brain axis in behaviour and brain disorders. Nature Reviews Microbiology, 19, 241–255.
Cryan, J. F., & Dinan, T. G. (2012). Mind-altering microorganisms: The impact of the gut microbiota on brain and behaviour. Nature Reviews Neuroscience, 13(10), 701–712.
Spencer, N. J., et al. (2026). Gut–brain communication: Types of sensory nerves and mechanisms of activation. Nature Reviews Gastroenterology & Hepatology.
O’Riordan, K. J., et al. (2025). The gut microbiota-immune-brain axis: Therapeutic implications. Cell Reports Medicine.
Grundeken, M. J., & El Aidy, S. (2025). Enteroendocrine cells: The gatekeepers of microbiome-gut-brain communication. npj Biofilms and Microbiomes.
Mukhopadhya, I., & Louis, P. (2025). Gut microbiota-derived short-chain fatty acids and their role in human health and disease. Nature Reviews Microbiology.
Ohara, T. E., & Hsiao, E. Y. (2025). Microbiota–neuroepithelial signalling across the gut–brain axis. Nature Reviews Microbiology.
Jiang, C., Nageeb, W. M., Batool, S., Hashish, A., Alkhawagah, S. M., Ibrahim, H. A. A., Zhu, W., Che, C., Li, X., Jin, M., Zhang, X., Ghonaim, A. H., Ren, M., & Li, S. (2026). Unraveling the gut microbiota-brain axis: Mechanisms, pathophysiology, and therapeutic opportunities. iScience, 29(6), 116224.
Sudo, N., Chida, Y., Aiba, Y., Sonoda, J., Oyama, N., Yu, X.-N., Kubo, C., & Koga, Y. (2004). Postnatal microbial colonization programs the hypothalamic-pituitary-adrenal system for stress response in mice. The Journal of Physiology, 558(1), 263–275.
Bravo, J. A., Forsythe, P., Chew, M. V., Escaravage, E., Savignac, H. M., Dinan, T. G., Bienenstock, J., & Cryan, J. F. (2011). Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proceedings of the National Academy of Sciences, 108(38), 16050–16055.
Bercik, P., Denou, E., Collins, J., Jackson, W., Lu, J., Jury, J., Deng, Y., Blennerhassett, P., Macri, J., McCoy, K. D., Verdu, E. F., & Collins, S. M. (2011). The intestinal microbiota affect central levels of brain-derived neurotrophic factor and behavior in mice. Gastroenterology, 141(2), 599–609.e3.
Tillisch, K., Labus, J., Kilpatrick, L., Jiang, Z., Stains, J., Ebrat, B., Guyonnet, D., Legrain-Raspaud, S., Trotin, B., Naliboff, B., & Mayer, E. A. (2013). Consumption of fermented milk product with probiotic modulates brain activity. Gastroenterology, 144(7), 1394–1401.e4.
Now we’d like to hear from you. Where are you noticing connections between mental and physical health in our work with clients?
Please leave a comment below.
Linda Mailhot, Coach, Redding, CA, USA says
will use and abide by the policy
Linda Hallstrom, Teacher, Huntley, IL, USA says
WOW!! Thank You for this Infographic. I’ve been studying this connection for the past 5 years. I see a direct relationship between IBS, stress & anxiety. Even though I have a ‘dietetic education’, sugar is my drug. Head knowledge doesn’t always connect to behavior.
Claudia Gary, Teacher, (suburb), DC, USA says
Having overcome an eating disorder in the distant past, I think this connection would be especially valuable to consider when treating eating disorders. For example, how do the gut’s responses to sugar and carbohydrates affect the brain? Also, how much are eating disorders driven by the “addictive” nature of sugar, whether that is true addiction or simply a result of insulin response?