May 8, 2023
New research is uncovering the connection between the gut and mental health. For anyone who has ever experienced a nervous gut, the signs have been there all along. Now there is scientific backing for why you can’t poop when you get sad - it turns out the gut influences mental health and vice-versa.
Further research into the gut-brain axis may mean new ways of targeting the symptoms of mental illness. This blog will explain the connection and its consequences in the following sections:
Let’s first establish what the gut-brain connection is and how it works.
The brain and the gut are connected by a variety of neural pathways. These pathways make up what is known as the gut-brain axis. The connection runs both ways, from brain to gut and gut to brain. This connection is the reason you get butterflies when you are nervous and the reason for the term “a gut feeling.”
The gut-brain axis is the connection between the central nervous system of the brain and the enteric nervous system of the GI tract. The connection occurs through enteric, vagal and spinal neural pathways. The axis is bi-directional, meaning not only can your mind affect your gut but your gut can affect your mind.
This connection ensures signalling as simple and crucial as communication of hunger through the vagus nerve to more complex, less understood interactions that may play a part in mental health and a host of neurological conditions.
Because the gut and the brain are connected through neural pathways, when inflammation occurs in the gut it may also reach and effect the brain. It can induce anxiety, depression and memory loss. This is due to the release of cytokines and neurotransmitters during inflammation which affect normal brain function.
Inflammation in the gut is often related to dysbiosis of the microbiome. Which is leading scientist to suggest that dysbiosis could be at the root of mental illness.
Dysbiosis is defined as the microbial imbalance of the microbiome. This means a lack of diversity either by way of too much of a certain kind of bacteria or not enough. When dysbiosis occurs, inflammation may be activated in the gut. That inflammation in turn effects pathways to the brain and may affect mood.
Cytokines and neurotransmitters released in the gut due to inflammation can lead to changes in neuroplasticity. Alterations in neuroplasticity can leave a person more vulnerable to feelings of anxiety and depression. Meaning that gut health and depression and anxiety are directly related.
A better understanding of the mental health and the gut-brain axis has lead to an increase interest in gut based treatments for symptoms like anxiety and depression. Multiple studies are currently underway to investigate the efficacy of treating psychiatric symptoms with Fecal Microbiota Transplants (FMT).
Fecal transplants are a bacterial therapy that targets microbes in the gut in order to balance the microbiota. The procedure is done by inserting stool from a healthy person into the colon of a patient. FMT delivers a diverse community of microbes to the gut, that are then able to help the host microbes recover to a more a balanced state. As it is understood, a balanced microbiome may lead to a decrease in anxiety and depression.
One such study is being performed at the Women’s College Hospital in Toronto, Canada. The study is looking at the connection between the gut microbiome and bipolar depression and whether such a disease can be treated effectively using fecal transplants.
In an interview for Designer Shit, the study's lead investigator, Dr Valerie Taylor explained that “depression is a disease where there's usually a deficiency in a brain neurotransmitter, called serotonin.” she went onto say, “We assume that that issue is a brain issue, except that most of your serotonin receptors are actually not in your brain. They're actually in your gut.” Meaning the gut could potentially be targeted in treatment for depression instead of focussing so heavily on treating the brain.
Mental illnesses are not the only brain related conditions being explored in connection to the gut-brain axis. Autism and Parkinson’s are also being looked into. Both are brain affecting conditions that often present with coinciding GI issues, making them prime candidates for bacterial focused treatments.
In a study out of Arizona State University, researchers saw improvements in both GI and cognitive symptoms of children with Autism after FMT. Though the study’s leaders admit more research is needed, early results are incredibly promising and show that the gut microbiota is playing a significant role in Autism.
This research could mean a new approach to the treatment of Autism and other neurological conditions with coinciding GI symptoms, such as Parkinson’s Disease.
Many with Parkinson’s Disease also have coinciding GI issues. It has been found that those with IBD present an increased risk for developing PD, due to alterations in the gut microbiota. Given the microbiome connection, bacterial therapies may be a viable treatment for Parkinson’s in the near future.
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The microbes in our guts have effects beyond the GI tract. Read from the New York Times about other brain conditions affected by the gut microbiota.
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