I remember when I first recognized the association of what I ate and my mood. Most people I shared this with thought this was a crazy notion. But what does research say?
There are various health conditions that impact people’s personality and overall mental health that have been associated with dysbiosis, which is a bacterial imbalance in the gastrointestinal tract that often gives people symptoms of maldigestion, fatigue, and skin manifestations. Some conditions that dysbiosis is known to contribute to are anxiety, depression, bipolar, multiple sclerosis (MS), Parkinson’s disease, bipolar disorder, and celiac disease.
You may be wondering how gut bacteria could impact someone’s emotions and mood. There is something called the gut-brain-axis. This essentially means that what is happening in the gastrointestinal tract impacts the brain, and what is happening in the brain can impact the gastrointestinal tract.
NEUROTRANSMITTERS: SEROTONIN
One way that the gut can affect the brain is through neurotransmitters, which are chemicals that send messages through the nerves in your body and control a whole bunch of systems in your body, including hormones, mood, memory, thoughts, sleep, stress, and digestion. The brain uses neurotransmitters such as serotonin, dopamine, norepinephrine, GABA, and histamine to send signals, and affect people’s mood, happiness, energy, and stress levels.
Serotonin is neurotransmitter, that is considered to be a happiness hormone. In addition to elevating the mood, it also helps with memory and digestion. Low levels of serotonin is associated with depression, anxiety, schizophrenia, bipolar, and other mood disorders. The vast majority of serotonin in our bodies isn’t even made by us. Our gut bacteria make 95% of our serotonin and the rest is made in the brain (carpenter 2012). Although bacteria produce the majority of serotonin, there are also certain bacteria in the gut that metabolize the serotonin precursor tryptophan and use it up, so that our bodies aren’t able to create as much serotonin (Kaur, 2019). So you can see how dysbiosis could lead to not enough production of serotonin, from either not having enough bacteria or having too much of the wrong bacteria and this can lead to mood changes and mental illness (Kaur, 2019). A similar story of other neurotransmitters and the gut could also be told.
Lets now take a look at how the gut may impact specific illnesses that affect the brain and mood such as Parkinson’s disease, MS, Celiac disease, bipolar disorder, and irritable bowel syndrome.
PARKINSON’S DISEASE AND MS
Parkinson’s disease and MS are considered neurodegenerative diseases. These diseases change people’s personalities. In Parkinson’s disease people lose dopaminergic neurons in the brain which leads to a decrease and eventually the inability to produce dopamine. Dopamine is another neurotransmitter, and it serves to give people feelings of pleasure, and help with memory and concentration, along with other functions such as movement. People with Parkinson’s disease tend to experience depression, anxiety, apathy, and lack of interest in things they used to enjoy. In MS people tend to have anxiety, depression, altered personalities, changes in emotions, and have cognitive decline. There is evidence that indicates these diseases are influenced and may even be triggered or caused by dysbiosis.
MS tends to begin after dysbiosis has occurred. Incredibly, some case studies have shown a complete reversal of MS after a fecal transplant, which is a procedure where they take a poop sample from a healthy individual and transplant it into the patient’s colon (Parodi, 2021). These fecal transplants can correct dysbiosis. There is also evidence from mice studies that giving probiotics may give major benefits to MS patients (Parodi, 2021). It seems that changing the gut bacteria has a significant role in MS.
Several mice studies have demonstrated an association between Parkinson’s disease and leaky gut, which is a phenomenon where the gut lining has increased permeability so that toxins and particles can pass through the gut lining and enter into the body. In Parkinson’s disease, there is a pathological protein called, α-synuclein, that is found in the brain and is associated with the neurodegenerative symptoms in Parkinson’s disease. When this protein was injected into the intestinal muscular lining of mice, it was able to travel through the vagus nerve and into the central nervous system (the brain) and cause destruction of dopaminergic neurons and produce parkinsonian symptoms (Parodi, 2021). It has been found that when mice that overexpress the a-synuclein protein are given fecal transplants from patients with Parkinson disease, they developed parkinsonian symptoms, whereas fecal transplants from healthy donors did not (Sampson, 2016). This means that the gut bacteria play a big role in whether the toxic protein α-synuclein can make it through the gut barrier and travel to the brain.
CELIAC DISEASE
Many people who have celiac disease or gluten sensitivity experience an impact on their mood and mental health after eating gluten. It has been found that people with celiac disease are more likely to have major depressive disorder, panic disorder, and bipolar disease (Carta, 2015). When people with celiac disease and gluten sensitivity went on a gluten free diet, they were found to have a reduction in depression (Busby, 2018).
BIPOLAR DISORDER
Neurotransmitter dysregulation, such as serotonin and norepinephrine, have been associated with bipolar disorder. As we discussed earlier, bacteria in our gut produce many of the neurotransmitters in our body, including serotonin and norepinephrine. This is one way that gut health may be impacting bipolar disorder. There has even been a case report of a fecal transplant curing someone of bipolar disease, and trials are currently being conducted to evaluate the safety and efficacy of this treatment (Parker, 2022).
IRRITABLE BOWEL SYNDROME
Anxiety and irritable bowel syndrome go hand and hand together. Irritable bowel syndrome is when people have abdominal pain and often have irregular bowel movements, either diarrhea or constipation. This syndrome can greatly decrease a person’s quality of life. One study showed that in patients with IBS 44% had anxiety and 84% depression, whereas compared to those without IBS only 8% had anxiety and 6% had depression (Banerjee 2017).
In conclusion, mental health is not just in the mind, and more accurately, it can be said that it is driven by the gut. I work with people’s gut health, to help restore gastrointestinal health, which in turn can help restore mental health. Schedule an appointment to discuss your complex health challenges and we can start your journey towards healing.
Resources
Banerjee, A., Sarkhel, S., Sarkar, R., & Dhali, G. K. (2017). Anxiety and Depression in Irritable Bowel Syndrome. Indian journal of psychological medicine, 39(6), 741–745. https://doi.org/10.4103/IJPSYM.IJPSYM_46_17
Busby, E., Bold, J., Fellows, L., & Rostami, K. (2018). Mood Disorders and Gluten: It’s Not All in Your Mind! A Systematic Review with Meta-Analysis. Nutrients, 10(11), 1708. https://doi.org/10.3390/nu10111708
Carpenter, D. S. (2012). That gut feeling. Monitor on Psychology. Retrieved December 2, 2022, from https://www.apa.org/monitor/2012/09/gut-feeling
Carta, M. G., Conti, A., Lecca, F., Sancassiani, F., Cossu, G., Carruxi, R., Boccone, A., Cadoni, M., Pisanu, A., Francesca Moro, M., & Demelia, L. (2015). The Burden of Depressive and Bipolar Disorders in Celiac Disease. Clinical practice and epidemiology in mental health : CP & EMH, 11, 180–185. https://doi.org/10.2174/1745017901511010180
Clapp, M., Aurora, N., Herrera, L., Bhatia, M., Wilen, E., & Wakefield, S. (2017). Gut microbiota’s effect on Mental Health: The gut-brain axis. Clinics and Practice, 7(4), 987.https://doi.org/10.4081/cp.2017.987
Kaur, H., Bose, C., and Mande, S. (2019). Tryptophan Metabolism by Gut Microbiome and Gut-Brain-Axis: An in silico Analysis. Frontiers in Neuroscience. Retrieved December 2, 2022, https://doi.org/10.3389/fnins.2019.01365
Parodi, B., Kerlero de Rosbo, N. (2021). The Gut-Brain Axis in Multiple Sclerosis. Is Its Dysfunction a Pathological Trigger or a Consequence of the Disease? Frontiers in Immunology. Retrieved December 2, 2022, fromhttps://doi.org/10.3389/fimmu.2021.718220
Parker, G., Spoelma, M. J., & Rhodes, N. (2022). Faecal microbiota transplantation for bipolar disorder: A detailed case study. Bipolar Disorders, 24(5), 559–563. https://doi.org/10.1111/bdi.13187
Sampson, T. R., Debelius, J. W., Thron, T., Janssen, S., Shastri, G. G., Ilhan, Z. E., Challis, C., Schretter, C. E., Rocha, S., Gradinaru, V., Chesselet, M.-F., Keshavarzian, A., Shannon, K. M., Krajmalnik-Brown, R., Wittung-Stafshede, P., Knight, R., & Mazmanian, S. K. (2016). Gut microbiota regulate motor deficits and neuroinflammation in a model of parkinson’s disease. Cell, 167(6). Retrieved December 2, 2022, from https://doi.org/10.1016/j.cell.2016.11.018