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The Gut Microbiome and Brain Health.

The Gut Microbiome and Brain Health.

Oct 20 Sean Orr, M.D.

 

How the Microbiome Influences Brain Health

 

The gut microbiome, a complex community of trillions of microorganisms residing in our gastrointestinal tract, has emerged as a critical player in overall health. Recent research has illuminated its significant impact on brain health, influencing everything from mood and cognition to the development of neurological disorders. This post explores the importance of the gut microbiome in brain health, drawing upon current scientific findings.

 

The Gut-Brain Axis: A Two-Way Communication System

The gut-brain axis refers to the bidirectional communication network that links the enteric nervous system (the gut's nervous system) with the central nervous system (the brain and spinal cord). This connection involves neural, hormonal, and immunological pathways, allowing the gut microbiome to influence brain function and vice versa [1].

 

Microbiome's Influence on Neurotransmitters

1. Serotonin Production

  • The gut produces approximately 90% of the body's serotonin, a neurotransmitter crucial for regulating mood, appetite, and sleep [2].
  • Certain gut bacteria can synthesize serotonin or influence its production, affecting emotional well-being.

 2. GABA and Other Neurotransmitters

  • Gut microbes like *Lactobacillus* and *Bifidobacterium* species can produce gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter that reduces neuronal excitability and anxiety [3].

 

Impact on Neurodevelopment and Behavior

 1. Early Life Microbiota and Brain Development

  • The composition of the gut microbiome during critical developmental periods can shape neural circuits and impact behavior later in life [4].
  • Dysbiosis, or imbalance in gut microbes, has been linked to neurodevelopmental disorders such as autism spectrum disorder (ASD) [5].

 2. Stress Response Modulation

  • The gut microbiome can modulate the hypothalamic-pituitary-adrenal (HPA) axis, influencing stress responses [6].
  • Probiotics have been shown to reduce stress-induced cortisol levels, suggesting therapeutic potential [7].

 

Role in Neuroinflammation and Neurodegeneration

1. Immune System Interaction

  • Gut microbes interact with the immune system, influencing systemic inflammation that can affect the brain [8].
  • Chronic inflammation is a risk factor for neurodegenerative diseases like Alzheimer's and Parkinson's disease.

2. Microbial Metabolites

  • Short-chain fatty acids (SCFAs), produced by bacterial fermentation of dietary fibers, have neuroprotective effects [9].
  • SCFAs like butyrate can cross the blood-brain barrier and modulate brain function.

 

Mental Health Implications

1. Depression and Anxiety

  • Studies have found differences in the gut microbiota composition of individuals with depression compared to healthy controls [10].
  • Fecal microbiota transplantation (FMT) from depressed patients to germ-free mice induced depressive-like behaviors in mice [11].

2. Probiotics as Psychobiotics

  • Certain probiotics, termed "psychobiotics," may confer mental health benefits by modulating the gut-brain axis [12].
  • Clinical trials have shown that probiotic supplementation can alleviate symptoms of depression and anxiety [13].

  

Diet, Microbiome, and Brain Health

1. Dietary Influence on Microbiota

  • Diet is a major determinant of gut microbiota composition.
  • Diets rich in fiber, polyphenols, and omega-3 fatty acids support a healthy microbiome [14].

 2. Mediterranean Diet and Cognitive Function

  • Adherence to a Mediterranean diet is associated with a reduced risk of cognitive decline and neurodegenerative diseases [15].
  • The diet's positive effects may be mediated through beneficial alterations in the gut microbiome.

 

 

Strategies to Support Gut-Brain Health

1. Probiotics and Prebiotics

  • Probiotics: Live beneficial bacteria that can be consumed through supplements or fermented foods (e.g., yogurt, kefir, sauerkraut).
  • Prebiotics: Non-digestible fibers that nourish beneficial gut bacteria (e.g., inulin, fructooligosaccharides).

 2. Dietary Interventions

  • Increase intake of fruits, vegetables, whole grains, and fermented foods.
  • Limit processed foods, excessive sugars, and unhealthy fats.

3. Lifestyle Factors

  • Stress Management: Chronic stress can disrupt the gut microbiome.
  • Regular Exercise: Physical activity positively influences gut microbial diversity [16].

  

Conclusion

The gut microbiome plays a pivotal role in brain health, influencing neurodevelopment, neurotransmitter production, immune function, and behavior. Understanding and nurturing this complex ecosystem opens new avenues for preventing and treating neurological and psychiatric disorders. By adopting dietary and lifestyle practices that promote a healthy microbiome, we can support optimal brain function and overall well-being. 

Support your gut-brain health by incorporating microbiome-friendly practices into your daily routine. Explore our range of supplements designed to promote a healthy gut at www.myactionpotential.com.

 

Disclaimer: The information provided in this blog post is for educational purposes only and is not intended to replace professional medical advice. Please consult a qualified healthcare provider for personalized recommendations.

 

References

  1. Cryan, J. F., & Dinan, T. G. (2012). Mind-altering microorganisms: The impact of the gut microbiota on brain and behaviour. Nature Reviews Neuroscience, 13(10), 701–712. https://doi.org/10.1038/nrn3346
  2. Yano, J. M., et al. (2015). Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis. Cell, 161(2), 264–276. https://doi.org/10.1016/j.cell.2015.02.047
  3. Lai, T. T., Liou, C. W., Tsai, Y. H., Lin, Y. Y., & Wu, W. L. (2023). Butterflies in the gut: the interplay between intestinal microbiota and stress. Journal of biomedical science, 30(1), 92. https://doi.org/10.1186/s12929-023-00984-6
  4. Stilling, R. M., et al. (2014). The neuropharmacology of butyrate: The bread and butter of the microbiota-gut-brain axis? Neurochemistry International, 99, 110–132. https://doi.org/10.1016/j.neuint.2016.06.011
  5. Ding, H. T., et al. (2017). Gut microbiota and autism: Key concepts and findings. Journal of Autism and Developmental Disorders, 47(2), 480–489. https://doi.org/10.1007/s10803-016-2960-9
  6. Moloney, R. D., et al. (2014). The microbiome: Stress, health and disease. Mammalian Genome, 25(1-2), 49–74. https://doi.org/10.1007/s00335-013-9488-5
  7. Kato-Kataoka, A., Nishida, K., Takada, M., Suda, K., Kawai, M., Shimizu, K., Kushiro, A., Hoshi, R., Watanabe, O., Igarashi, T., Miyazaki, K., Kuwano, Y., & Rokutan, K. (2016). Fermented milk containing Lactobacillus casei strain Shirota prevents the onset of physical symptoms in medical students under academic examination stress. Beneficial microbes, 7(2), 153–156. https://doi.org/10.3920/BM2015.0100
  8. Fung, T. C., Olson, C. A., & Hsiao, E. Y. (2017). Interactions between the microbiota, immune and nervous systems in health and disease. Nature neuroscience, 20(2), 145–155. https://doi.org/10.1038/nn.4476
  9. Dalile, B., Van Oudenhove, L., Vervliet, B., & Verbeke, K. (2019). The role of short-chain fatty acids in microbiota-gut-brain communication. Nature reviews. Gastroenterology & hepatology, 16(8), 461–478. https://doi.org/10.1038/s41575-019-0157-3
  10. Jiang, H., et al. (2015). Altered gut microbiota profile in patients with generalized anxiety disorder. Journal of Psychiatric Research, 63, 1–7. https://doi.org/10.1016/j.jpsychires.2018.07.007
  11. Zheng, P., et al. (2016). Gut microbiome remodeling induces depressive-like behaviors through a pathway mediated by the host’s metabolism. Molecular Psychiatry, 21(6), 786–796. https://doi.org/10.1038/mp.2016.44
  12. Dinan, T. G., & Cryan, J. F. (2017). Gut instincts: microbiota as a key regulator of brain development, ageing and neurodegeneration. The Journal of physiology, 595(2), 489–503. https://doi.org/10.1113/JP273106
  13. Wallace, C. J. K., & Milev, R. (2017). The effects of probiotics on depressive symptoms in humans: a systematic review. Annals of general psychiatry, 16, 14. https://doi.org/10.1186/s12991-017-0138-2
  14. Ghosh, T. S., Rampelli, S., Jeffery, I. B., Santoro, A., Neto, M., Capri, M., Giampieri, E., Jennings, A., Candela, M., Turroni, S., Zoetendal, E. G., Hermes, G. D. A., Elodie, C., Meunier, N., Brugere, C. M., Pujos-Guillot, E., Berendsen, A. M., De Groot, L. C. P. G. M., Feskins, E. J. M., Kaluza, J., … O'Toole, P. W. (2020). Mediterranean diet intervention alters the gut microbiome in older people reducing frailty and improving health status: the NU-AGE 1-year dietary intervention across five European countries. Gut, 69(7), 1218–1228. https://doi.org/10.1136/gutjnl-2019-319654
  15. Valls-Pedret, C., Sala-Vila, A., Serra-Mir, M., Corella, D., de la Torre, R., Martínez-González, M. Á., Martínez-Lapiscina, E. H., Fitó, M., Pérez-Heras, A., Salas-Salvadó, J., Estruch, R., & Ros, E. (2015). Mediterranean Diet and Age-Related Cognitive Decline: A Randomized Clinical Trial. JAMA internal medicine, 175(7), 1094–1103. https://doi.org/10.1001/jamainternmed.2015.1668
  16. Allen, J. M., Mailing, L. J., Niemiro, G. M., Moore, R., Cook, M. D., White, B. A., Holscher, H. D., & Woods, J. A. (2018). Exercise Alters Gut Microbiota Composition and Function in Lean and Obese Humans. Medicine and science in sports and exercise, 50(4), 747–757. https://doi.org/10.1249/MSS.0000000000001495
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