Gut – Brain Connections: How colon bacteria affect mental health

Grand discoveries which explain long sought-after connections between different phenomena in our bodies come by taking keen observations and methodically teasing apart the threads that connect the web of our metabolism.  Researchers knew that some connection between autoimmune disorders, anxiety symptoms, and gut bacteria existed.  This article lays out how researchers at several institutions tried to peal back another layer of understanding using mice.

They first created a set of germ-free mice by either antibiotic delivery or through breeding.  These mice demonstrated a reduced ability to recognize when a dangerous signal was removed.  When they looked at the RNA of microglia (brain immune cell type) in these mice, they noted changes in RNA levels for specific genes.  The altered gene levels concerned proteins that remodeled synapse (connections) between brain cells.  Healthy mice did not show these changes.   They hypothesize that the changes in pruning of brain cell connections could contribute to the psychiatric changes.

Of course, researchers wondered if they could fix the problem they created.  They restored gut flora to affected mice at different ages.  They found that only when the bacteria were added right after birth, would the microglia function normally.

The study authors further commented on the possible connections to varied diseases from Autism to Parkinson’s or PTSD.  They admitted that the road to full understanding had a long way to go but were hopeful.

In the meantime as we wait for more research, at Sanctuary, we work on keeping patient’s gut bacteria in top shape as much as possible.  Discerning what our patient’s GI tracts need requires study, good listening, and testing.  While everyone needs a low inflammatory diet avoiding preservatives, pesticides, and processed foods, fine tuning patients for their preference and specific health needs requires time.  When we get that on target, we see not only GI symptoms improve, but we often see joint pains improve, mood improve, energy improve, and autoimmune diseases improve.

In helping patients live a healthier more abundant life, the gut is an important foundation for brain health and other body systems.


Original Article:

Coco Chu, Mitchell H. Murdock, Deqiang Jing, Tae Hyung Won, Hattie Chung, Adam M. Kressel, Tea Tsaava, Meghan E. Addorisio, Gregory G. Putzel, Lei Zhou, Nicholas J. Bessman, Ruirong Yang, Saya Moriyama, Christopher N. Parkhurst, Anfei Li, Heidi C. Meyer, Fei Teng, Sangeeta S. Chavan, Kevin J. Tracey, Aviv Regev, Frank C. Schroeder, Francis S. Lee, Conor Liston & David Artis. The microbiota regulate neuronal function and fear extinction learning. Nature, 2019 DOI: 10.1038/s41586-019-1644-y


Thanks to Science Daily:

Weill Cornell Medicine. “Gut instincts: Researchers discover first clues on how gut health influences brain health.” ScienceDaily. ScienceDaily, 23 October 2019. <>.



Others research links:

Belkaid, Y. & Hand, T. W. Role of the microbiota in immunity and inflammation. Cell 157, 121–141 (2014).

Hill, D. A. & Artis, D. Intestinal bacteria and the regulation of immune cell homeostasis. Annu. Rev. Immunol. 28, 623–667 (2010).

Vuong, H. E., Yano, J. M., Fung, T. C. & Hsiao, E. Y. The microbiome and host behavior. Annu. Rev. Neurosci. 40, 21–49 (2017).

Mielcarz, D. W. & Kasper, L. H. The gut microbiome in multiple sclerosis. Curr. Treat. Options Neurol. 17, 344 (2015).

Krajmalnik-Brown, R., Lozupone, C., Kang, D. W. & Adams, J. B. Gut bacteria in children with autism spectrum disorders: challenges and promise of studying how a complex community influences a complex disease. Microb. Ecol. Health Dis. 26, 26914 (2015).

Zheng, P. et al. Gut microbiome remodeling induces depressive-like behaviors through a pathway mediated by the host’s metabolism. Mol. Psychiatry 21, 786–796 (2016).

Hoban, A. E. et al. Regulation of prefrontal cortex myelination by the microbiota. Transl. Psychiatry 6, e774 (2016).

Braniste, V. et al. The gut microbiota influences blood-brain barrier permeability in mice. Sci. Transl. Med. 6, 263ra158 (2014).

Sanctuary Functional Medicine, under the direction of Dr Eric Potter, IFMCP MD, provides functional medicine services to Nashville, Middle Tennessee and beyond. We frequently treat patients from Kentucky, Alabama, Mississippi, Georgia, Ohio, Indiana, and more... offering the hope of healthier more abundant lives to those with chronic illness.

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