The microbes in your lower intestine are like Rodney Dangerfield—they get no respect. So, I am guessing that the bacteria in your bowels helping you digest turkey and pumpkin pie are near the bottom of your list of things you will be thanking God for this Thanksgiving Day. Perhaps this article will change that.
I have written previously about the benefits of increasing our gut bacteria. A study shows that humans who were richly endowed with anti-inflammatory bacterial species in their gut were much less likely to be plagued by obesity.1 Another study reveals that what you eat determines the diversity of your gut bacteria.2
Now, new research shows the likelihood that gut intestinal microbiota influence brain development and neurological behavior.3 These studies follow previous findings that demonstrated that mammals raised in sterile, germ-free conditions exhibited negative behaviors resulting from impaired brain physiology and neurochemistry.
The new studies reveal that gut microbes influence our brains through certain hormones, immune system molecules, and metabolites they produce. For example, a study of residents of Walkerton, Canada, who, over a short time period, ingested contaminated drinking water—thus, severely damaging their gut bacteria—suffered widespread depression and anxiety disorders that persisted for eight years.4 Another study showed that certain gut microbes break down complex carbohydrates to produce the fatty acid butyrate, which strengthens the blood-brain barrier.5 A complementary study demonstrated that disruption of the brain-gut-microbiota axis likely contributes to the development of Parkinson’s disease.6 Yet another study established that gut microbes directly alter neurotransmitter levels. Specifically, this study showed that certain metabolites from gut microbes promote serotonin production.7 Still another study reveals that the health condition of gut microbiota during the host’s early development might affect neurodevelopment, especially in males,8 which has touched off speculation about autism disorders.
Emerging, not-yet-published research findings show that, in at least one part of the brain, gut microbes influence the formation of the fatty sheathings that insulate nerve fibers.9 An older published study shows a probable link between multiple sclerosis and the disabling of a metabolite produced by certain types of gut bacteria.10
As this growing research demonstrates, if you want a healthy, high-functioning brain and an optimal psychological state of mind, it will be important to take good care of your gut microbiota. As your mother said, “Eat your vegetables”—especially the green ones.
Our Creator meticulously designed a diverse array of gut microbes to ensure that our brains can function for many decades at a high-capacity level that enables us to enjoy creation and to fulfill all the purposes for which He created us. This Thanksgiving, select a menu that will be kind to your gut microbes and take some time to thank God for the marvelous way He designed your gut bacteria.
- Emmanuelle Le Chatelier et al., “Richness of Human Gut Microbiome Correlates with Metabolic Markers,” Nature 500 (August 2013): 541–46, doi:10.1038/nature12506.
- Aurélie Cotillard et al., “Dietary Intervention Impact on Gut Microbial Gene Richness,” Nature500 (August 2013): 585–88, doi:10.1038/nature12480.
- Peter Andrey Smith, “The Tantalizing Links between Gut Microbes and the Brain,” Nature 526 (October 2015): 312–14, doi:10.1038/526312a.
- John K. Marshall et al., “Eight Year Prognosis of Postinfectious Irritable Bowel Syndrome Following Waterborne Bacterial Dysentery,” Gut 59 (May 2010): 605–11, doi:10.1136/gut.2009.202234.
- Viorica Braniste et al., “The Gut Microbiota Influences Blood-Brain Barrier Permeability in Mice,” Science Translational Medicine 6 (November 2014): 263ra158, doi:10.1126/scitranslmed.3009759.
- A. Mulak and B. Bonaz, “Brain-Gut-Microbiota Axis in Parkinson’s Disease,” World Journal of Gastroenterology 21 (October 2015): 10609–20.
- J. M. Yano et al., “Indigenous Bacteria from the Gut Microbiota Regulate Host Serotonin Biosynthesis,” Cell 161 (April 2015): 264–76, doi:10.1016/j.cell.2015.02.047.
- E. Jašarević et al., “Alterations in the Vaginal Microbiome by Maternal Stress Are Associated with Metabolic Reprogramming of the Offspring Gut and Brain,” Endocrinology 156 (September 2015): 3265–76, doi:10.1210/en.2015-1177.
- Smith, “The Tantalizing Links,” 312–14.
- Yun Kyung Lee et al., “Proinflammatory T-Cell Responses to Gut Microbiota Promote Experimental Autoimmune Encephalomyelitis,” Proceedings of the National Academy of Sciences, USA 108, Supplement 1 (March 2011): 4615–22, doi:10.1073/pnas.1000082107.