The Gut-Brain Axis: Traditional Chinese Medicine 2.0?

When most people think complementary and alternative medicine (CAM), they often think of Traditional Chinese Medicine, like acupuncture and herbal remedies. While these treatments are viewed by some as Hocus Pocus (#halloween classics), that may be not because they aren’t grounded in science, but because the science hasn’t caught up with these age-old therapeutic approaches. If I could pick one word to summarize my limited understanding of Chinese medicine, it would be Complex.

Eastern medicine approaches often emphasize holistic thinking (the whole is greater than the sum of its parts kinda stuff), trying to conceptualize many different factors within the body1. The Western philosophy of science, in contrast, is reductionistic. This means that most scientific studies try to simplify things (like the body) down to individual components (like cells), but this approach often loses the bigger picture. As a result, Eastern and Western approaches to medicine haven’t meshed the best.

As our understanding of the brain has developed, I would use the same word to describe it: complex. The brain is the most interconnected organ in our body, integrating information from all of the body. While many brain-body links could be important for Chinese medicine, I want to focus on one in particular: The Gut. Research on how the Gut can influence the brain (the Gut-Brain Axis) has exploded over the last several years, leading to some exciting discoveries2.

Neurons (brain cells) use special chemicals called neurotransmitters to communicate information, and many of these neurotransmitters are at least partially, if not fully, made in the gut and heavily influenced by diet3. One neurotransmitter, Serotonin, for example, is made from a particular nutrient called Tryptophan, and serotonin levels can fluctuate based on how much Tryptophan is in your diet4. Serotonin is really important for being able to regulate your mood and promoting neuroplasticity. Fun fact: Tryptophan is found in dark chocolate, so next time your craving some 70% cocoa just remind yourself that it could be your brain letting you know it wants some more serotonin to help boost your mood (I love this excuse to each dark chocolate covered almonds). So now think about all the different nutrients that you eat and all of the different neurotransmitters your brain uses. Is your head spinning yet from all of this complexity? Well, strap yourself in, because the Gut-Brain axis is even more complex. There is an entire ecosystem of bacteria inside of your gut that is involved in regulating the transformation of nutrients to neurotransmitters. The activity of this Microbiota was found to regulate serotonin production, which in turn was related to brain networks involved in anxiety and reward processing5. To summarize, the Gut and the Microbiota are able to strongly influence the brain by regulating neurotransmitters, and this process is anything but simple.

Returning to Traditional Chinese Medicine, it seems like this therapeutic approach might be given a new life through the Gut-Brain Axis. Both Chinese medicine and the Gut-Brain axis are incredibly complex, and its only been recently that science has developed some tools to deal with that complexity. Both Chaos Theory6 (what Jeff Goldblum is talking about in Jurassic Park) and machine learning are great tools for helping neuroscientists understand complicated data without needing to oversimplify it. Between these tools and our new understanding of the Gut-Brain Axis, science is starting to catch up with age-old CAM and it’s becoming clear it was neuroCAM all along.

Ty the Neuro Guy is a cognitive neuroscience graduate student at the University of Utah and the Research Director for Branch Out Neurological Foundation. Inspired by the creative knowledge translation, Ty helps promote scientific literacy through this blog. You can look forward to an article each month helping explain the science of NeuroCAM. If you have any questions or comments about this article or overall blog, feel free to email Ty McKinney at research@branchoutfoundation.com. 

References

  1. Zhao, L., Nicholson, J. K., Lu, A., Wang, Z., Tang, H., Holmes, E., ... & Lindon, J. C. (2012). Targeting the human genome–microbiome axis for drug discovery: inspirations from global systems biology and traditional Chinese medicine. Journal of proteome research11(7), 3509-3519.
  2. Osadchiy, V., Martin, C. R., & Mayer, E. A. (2018). The Gut-Brain Axis and the Microbiome: Mechanisms and Clinical Implications. Clinical Gastroenterology and Hepatology.
  3. Heitkemper, M. M., & Marotta, S. F. (1983). Development of neurotransmitter enzyme activity in the rat gastrointestinal tract. American Journal of Physiology-Gastrointestinal and Liver Physiology244(1), G58-G64.
  4. Culley, W. J., Saunders, R. N., Mertz, E. T., & Jolly, D. H. (1963). Effect of a tryptophan deficient diet on brain serotonin and plasma tryptophan level. Proceedings of the Society for Experimental Biology and Medicine113(3), 645-648.
  5. Osadchiy, V., Labus, J. S., Gupta, A., Jacobs, J., Ashe-McNalley, C., Hsiao, E. Y., & Mayer, E. A. (2018). Correlation of tryptophan metabolites with connectivity of extended central reward network in healthy subjects. PloS one13(8), e0201772.
  6. Bell, I. R., Koithan, M., & Pincus, D. (2012). Methodological implications of nonlinear dynamical systems models for whole systems of complementary and alternative medicine. Complementary Medicine Research19(Suppl. 1), 15-21.