The Second Brain and Depression

Julia Malkowski, ND, DC | February 22, 2022

Have you noticed an increasing prevalence of depression in your practice recently?  Not only have reports of depression increased since the pandemic, but post-COVID depression has been reported in up to 40% of those recovered. Strong links exist between the gut microbiome and mental health. Evaluating the gut may benefit neuronal serotonin synthesis and brain derived neurotrophic factor. Addressing diet and microbial mediators, such as short chain fatty acids, may influence inflammation, a potential link in the pathogenesis of depression. Assessing and addressing microbiome abundance and diversity may be the most definite functional medicine application of the gut-brain axis.

The gut-brain axis is a highly complex system that merits clinical consideration. One mechanism of action may be the gut microbiome’s influence over serotonin synthesis and brain derived neurotropic factor (BDNF). Depressed individuals have lower levels of BDNF and the gut microbiome has been noted to play a role, specifically Lactobacilli species. It is estimated that up to 95% of serotonin is produced in the gut. Optimal levels of Clostridia are a factor in gut serotonin synthesis. Gut derived serotonin stimulates neuronal serotonin expression via the Vagus nerve.

Inflammation is one consideration regarding the pathogenesis of depression. Pro-inflammatory levels of cytokines are noted in inflammatory bowel disease (IBD) and depression. IL-6 has been noted to be significantly elevated in depressed individuals. The standard American diet (SAD) may be associated with depression. A SAD, characterized by excess fats, proteins and processed food items, is associated with inflammation and elevated Parabacteroides. Lactobacillus may be associated as well, as this bacterium plays a role in modulating inflammatory cascades. The gut microbiome is greatly influenced by diet, that provides microbial accessible substrates that support productive commensal bacteria.

A study has shown that women suffering depression consumed less fiber and had lower fecal short chain fatty acids (SCFAs) than non-depressed women. More research is needed in this area, yet soluble fiber is a significant contributing factor to a healthy and diverse microbiome. Soluble fiber feeds our gut as prebiotics, the bacteria in our gut ferment these, and produce SCFAs. These SCFAs act as microbial mediators communicating with the brain via the Vagus nerve. The effect may be reduced inflammatory signals to our brain, as well as increased serotonin and BDNF synthesis. Furthermore, probiotics have been suggested to improve synaptic signaling pathways and neuronal connections.

Studies consistently indicate that greater microbial abundance and diversity is associated with positive health outcomes. Depression is associated with gut microbiome dysbiosis characterized by decreased abundance and diversity. Those diagnosed with depression have been shown to have lower levels of F. prausnitzii, Lachnospiraceae, Bifidobacterium and Dialister species, and elevated levels of Allistipes and Parabacteroides. Supporting a robust and diverse microbiome may be a useful strategy regarding those suffering depression.

Mental status and mood are a complex physiological and psychological phenomenon. While more research is needed, utilizing the latest discoveries regarding the gut-brain axis may benefit our patients. A dietary regime inclusive of adequate soluble fiber to enhance microbial abundance and diversity provides a low risk intervention for depression. While attending to the gut-brain axis may improve patient outcomes, this approach is not meant to circumvent behavioral, psychological and pharmacological interventions as appropriate.

 

References

  1. Capuco, A., Urits, I., Hasoon, J., Chun, R., Gerald, B., Wang, J. K., Kassem, H., Ngo, A. L., Abd-Elsayed, A., Simopoulos, T., Kaye, A. D., & Viswanath, O. (2020). Current Perspectives on Gut Microbiome Dysbiosis and Depression. Advances in therapy, 37(4), 1328–1346. https://doi.org/10.1007/s12325-020-01272-7
  2. Fontana, A., Manchia, M., Panebianco, C., Paribello, P., Arzedi, C., Cossu, E., Garzilli, M., Montis, M. A., Mura, A., Pisanu, C., Congiu, D., Copetti, M., Pinna, F., Carpiniello, B., Squassina, A., & Pazienza, V. (2020). Exploring the Role of Gut Microbiota in Major Depressive Disorder and in Treatment Resistance to Antidepressants. Biomedicines, 8(9), 311. https://doi.org/10.3390/biomedicines8090311
  3. Limbana, T., Khan, F., & Eskander, N. (2020). Gut Microbiome and Depression: How Microbes Affect the Way We Think. Cureus, 12(8), e9966. https://doi.org/10.7759/cureus.9966

The Power of the Circadian Rhythm: Surveying the Many Health Benefits of Melatonin

Krista Anderson Ross, ND

March 2, 2022 at 9:30 AM and 12 PM Pacific

Approximately 60 minutes with Q&A

Learning Objectives:
  1. Learn how and when the body secretes melatonin and its primary functions
  2. Review the relationship between melatonin and cortisol
  3. Explore how melatonin is associated with more than just sleep/wake cycles (immune function, mental health, inflammation, etc.)
  4. Determine the impact that age and lifestyle choices may have on native melatonin secretion
  5. Consider research on the safety of supplementing throughout the life cycle including pregnancy and childhood
  6. Review naturally occurring melatonin in food (phytomelatonin)
  7. Obtain supplementation considerations

Disclaimer: All information given about health conditions, treatment, products, and dosages are for educational purposes only and do not constitute medical advice.

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