The gut-brain-microbiota axis
When your gut health is not optimal, it is not uncommon to have issues with your mental health too and vice versa.
If you’re feeling low, anxious or experiencing mood swings it could be related to your gut.
Indeed, the gut and the brain are interconnected. They communicate to each other via the vagus nerve like a walkie-talkie where signals are sent both ways between the two organs (1).
Remember the butterfly feelings on a first date or the urge to go to the toilet before a stressful event? This is them talking!
Our microbiota (our gut bugs) is so powerful that it is able to produce neurotransmitters such as serotonin, dopamine and GABA, which affect our nervous system function. Serotonin and dopamine play a crucial role in our mood and emotions, and GABA is also crucial for regulating anxiety (1,2).
If a dysbiosis (a bad mix of the wrong type of bacteria) or intestinal permeability (also called leaky gut) is present in the gut, the production of those neurotransmitters is at risk.
The gut-brain axis is now well established in scientific papers and research shows a link between functional gastrointestinal disorders and central nervous disorders such as autism and anxiety-depressive behaviours (3).
In fact, almost every type of disease has a gastro-intestinal bacterial dysbiosis connection somewhere (4,5).
This is why I will always look at your gut health if you come to my practice!
Processed foods, low fibre diets, environmental pollutants, lack of sleep, lack of chewing, lack of exercise, chronic stress, poor dental hygiene, antibiotics, excessive alcohol consumption and high sugar intake are all risk factors of an impaired microbiota (and this list is not exhaustive!) (5,6,7,8,9,10,11,12).
This can be overwhelming to read. The gut-brain-microbiota axis is complex but the good news is that nutrition and lifestyle medicine have a direct and positive impact on reducing these harmful bacteria.
References
1.Appleton, J. (2018) The Gut-Brain Axis: Influence of Microbiota on Mood and Mental Health, PubMed Central (PMC). Integr Med. 2018 Aug; 17(4): 28–32.Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6469458/
2. Serra, D., Almeida, L. and Dinis, T. (2018) ‘Dietary polyphenols: A novel strategy to modulate microbiota-gut-brain axis’ Trends in Food Science & Technology, [online] 78, pp.224-233. Available at: https://doi.org/10.1016/j.tifs.2018.06.007
3. Carabotti. M et al. (2015) The Gut-Brain Axis: Interactions Between Enteric Microbiota, Central And Enteric Nervous Systems. [online] PubMed. Available at: <https://pubmed.ncbi.nlm.nih.gov/25830558/>
4. Shreiner, A., et al., 2015. The gut microbiome in health and in disease. Current Opinion in Gastroenterology, [online] 31(1), pp.69-75. Available at: <http://10.1097/MOG.0000000000000139> [Accessed 9 December 2020].
5. Nicolle, L. and Woodriff Beirne, A. (2010) Biochemical Imbalances in Disease: A Practioner's Handbook, Singing Dragon.
6. Cao, H., et al. (2017) ‘Dysbiosis contributes to chronic constipation development via regulation of serotonin transporter in the intestine’. Scientific Reports, [online] 7(1). Available at: https://www.nature.com/articles/s41598-017-10835-8
7. Codella, R., Luzi, L and Terruzzi, I. (2018) ‘Exercise has the guts: How physical activity may positively modulate gut microbiota in chronic and immune-based diseases’ Digestive and Liver Disease, [online] 50(4), pp.331-341. Available at: http://10.1016/j.dld.2017.11.016
8. Jin, Y., et al. (2017) ‘Effects of environmental pollutants on gut microbiota’ Environmental Pollution, [online] 222, pp.1-9. Available at: https://doi.org/10.1016/j.envpol.2016.11.045
9. Monda, V., et al. (2017) ‘Exercise Modifies the Gut Microbiota with Positive Health Effects’ Oxidative Medicine and Cellular Longevity, [online] 2017, pp.1-8. Available at: https://doi.org/10.1155/2017/3831972
10. Rogers, G., et al (2016) ‘From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways’. Molecular Psychiatry, [online] 21(6), pp.738-748. Available at: http://10.1038/mp.2016.50
11. Sen, T., et al. (2017) ‘Diet-driven microbiota dysbiosis is associated with vagal remodeling and obesity’ Physiology & Behavior, [online] 173, pp.305-317. Available at: https://doi.org/10.1016/j.physbeh.2017.02.027
12. Valdes, A., et al. (2018) ‘Role of the gut microbiota in nutrition and health’ BMJ, [online] p.k2179. Available at: https://doi.org/10.1136/bmj.k2179