Are you suffering from relentless gut symptoms? Are you experiencing relentless mental health ups and downs? Today’s blog post is going to explain how these two things are intrinsically linked, and how your mental health may just improve from addressing your gut health.
The human body is a complex ecosystem, consisting of trillions of microorganisms that reside within our gut. These microorganisms, collectively known as the gut microbiome, play a crucial role in maintaining our physical and mental wellbeing. In recent years, research has uncovered a fascinating link between the gut microbiome and mental health, revealing the profound influence that gut bacteria can have on our brain function and emotional wellbeing via the complexities of the vagus nerve. We’ve all heard about the gut-brain connection, but this post will delve into the intricacies of that connection, discuss how this communication actually occurs, and draw on recent research that highlights this link to various health conditions.
The Gut-Brain Axis: A Bidirectional Communication Pathway
The gut-brain axis is a pathway that connects the gastrointestinal tract and the central nervous system. It allows for constant interaction and information exchange between the gut and the brain. The gut microbiome, with its diverse community of bacteria, fungi, and viruses, plays a pivotal role in this communication process through microbial signalling. The key component of this channel is the vagus nerve which serves as the communication highway, linking emotional and cognitive centres of the brain with enteric gastrointestinal functions. This long winding nerve extends from the brain stem, innervating all the way down to and throughout the digestive tract. It plays a vital role in transmitting signals and information between the gut and the brain.
Here’s more on how the gut-brain axis works:
Regulation of Neurotransmitters
The gut microbiome produces neurotransmitters such as serotonin, dopamine, and gamma-aminobutyric acid (GABA). As we know, these neurotransmitters regulate mood, cognition, and behaviour. Studies have shown that alterations in the gut microbiome composition can affect the production and availability of these neurotransmitters, potentially leading to mood disorders such as depression and anxiety and having an impact on neuropsychiatric disorders.
Immune System Modulation
The gut microbiome influences the development and regulation of the immune system. Emerging research suggests that immune dysregulation, caused by an imbalance in gut bacteria and/or poor integrity of the gut lining, can contribute to the development of mental health disorders. For example, individuals with psychiatric conditions have been found to exhibit altered immune responses and increased levels of systemic inflammation and gut inflammation.
Stress Response
The gut microbiome is intricately involved in the regulation of the body's stress response system. Studies have shown that certain gut bacteria can modulate the production of stress hormones, such as cortisol. This influences the function of the hypothalamic-pituitary-adrenal (HPA) axis, which plays a key role in stress regulation. Dysregulation of this axis has been implicated in mood disorders and anxiety, and related to poor tone of the vagus nerve.
Neuroinflammation
Inflammation in the brain has been linked to various mental health conditions, including depression and schizophrenia. The gut microbiome helps regulate systemic inflammation, and disruptions in gut microbial composition can contribute to chronic inflammation and subsequent neuroinflammation.
After reading these few topics, what are your first thoughts? Are there any realisations or conditions that spring to mind?
Here’s my initial thoughts… How is the gut microbiome not one of the first and foremost components addressed in those with neuropsychiatric disorders and neurodegenerative disease?
Luckily in more recent years, there has been some investigation to understand the diversity of the gut microbiome in individuals with mental health and neurological conditions, including bi-polar, schizophrenia, Parkinson’s and Alzheimer’s. It has become clear that many of these individuals do in fact have gut dysbiosis and gut hyper-permeability (“leaky gut”), linking specific microbial configurations with various conditions. This also includes the world of neurodivergence, which is another topic of its own!
Due to the way the gut microbiome influences mood, cognition, stress response, neuroinflammation, and neurotransmitter dysregulation, there has been emerging evidence to suggest that alterations in the gut microbiome composition can contribute to and further progress neurocognitive impairment, for example those with bi-polar disorder or Alzheimer’s disease. Here’s a catch-22… antipsychotic medications are known to heavily disrupt the gut microbiome and cause further neuroinflammation. This is why there has been a recent push for alternative or conjunctive treatment options that include the use of probiotics or psychobiotics.
This microbiome-centred treatment may be an effective approach for many conditions or symptoms alike including mood swings, depression, anxiety and brain fog. More research is certainly warranted in this area, but it’s pretty riveting stuff! What do you think?
As you can see the gut-brain axis is a complex, intricate, and sensitive topic. But after reading today's blog post, whether you have mental health symptoms or not, I hope you take this as your sign to optimise, prioritise or investigate your gut health!
References:
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Cryan, D. M., & Dinan, T. G. (2012). Mind-altering microorganisms: the impact of the gut microbiota on brain and behavior. Nature Reviews Neuroscience, 13(10), 701-712.
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Dai, W., Liu, J., Qiu, Y., Teng, Z., Li, S., Yuan, H., Huang, J., Xiang, H., Tang, H., Wang, B., Chen, J., & Wu, H. (2022). Gut Microbial Dysbiosis and Cognitive Impairment in Bipolar Disorder: Current Evidence. Frontiers in pharmacology, 13, 893567. https://doi.org/10.3389/fphar.2022.893567
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Foster, J. A., & McVey Neufeld, K. A. (2013). Gut-brain axis: how the microbiome
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Kelly, J. R., Kennedy, P. J., Cryan, J. F., Dinan, T. G., Clarke, G., & Hyland, N. P. (2015). Breaking down the barriers: the gut microbiome, intestinal permeability and stress-related psychiatric disorders. Neuroscience and Biobehavioral Reviews, 55, 396-408.
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Munawar, N., Ahsan, K., Muhammad, K., Ahmad, A., Anwar, M. A., Shah, I., Al Ameri, A. K., & Al Mughairbi, F. (2021). Hidden Role of Gut Microbiome Dysbiosis in Schizophrenia: Antipsychotics or Psychobiotics as Therapeutics?. International journal of molecular sciences, 22(14), 7671. https://doi.org/10.3390/ijms22147671
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Slyepchenko, A., Carvalho, A. F., Cha, D. S., Kasper, S., McIntyre, R. S. (2014). Gut emotions - mechanisms of action of probiotics as novel therapeutic targets for depression and anxiety disorders. CNS & Neurological Disorders - Drug Targets, 13(10), 1770-1786.
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Zheng, P., Zeng, B., Zhou, C., Liu, M., Fang, Z., Xu, X., ... & Xie, P. (2016). Gut microbiome remodeling induces depressive-like behaviors through a pathway mediated by the host's metabolism. Molecular Psychiatry, 21(6), 786-796