Brain Health and the Gut Microbiome: How the new Jona platform analyzes Brain Health

What happens in your gut can directly impact your brain and vice versa. Emerging research on the gut-brain axis highlights the gut microbiome's role in producing neurotransmitters such as serotonin, commonly known for its capacity in boosting mood. Interestingly enough, ~90% of the Serotonin is produced in the cells lining your gastrointestinal tract, meaning only about 10% is produced in your brain. Your gut-brain connection is a major hub for regulatory functions in your body and It has become increasingly apparent that thisneuroimmune communicationis critical for GI homeostasis and prevention of disease.The GI tract can be considered an extension of the nervous system, from entrance to exit it is riddled with nerves that fire signals throughout the body, and is tied to every individual'sexposome.

In a broad sense, brain health refers to the state of an individual's brain relative to functioning across sensory, cognitive, socio-emotional, behavioral and motor domains. Brain health can be disrupted in many ways, including discontinuous  growth, structural damage, or impaired function, with neurodegenerative diseases and congenital conditions. Given that 1 in 5 adults experience mental illness, it is crucial to recognize mental illness’s role in overall brain health and actively work to improve mental well-being to enhance cognitive function.

The gut-brain axis is the bidirectional communication pathway between the central nervous system (CNS) and the gastrointestinal (GI) tract. This communication is regulated by neural pathways, hormones and immune signals, particularly through the winding vagus nerve, which is the largest cranial nerve extending from your brain to your large intestine. The vagus nerve begins at your brainstem and passes through your neck, chest, heart, lungs, abdomen and digestive tract. The vagus nerve allows your central nervous system to aid in controlling involuntary processes like gastric emptying, breathing and heart rate. Beyond digestion and cognition, the gut-brain connection loops in several other body systems, including the endocrine system and circulatory system — all roads lead to the gut. The gut and the brain operate synergistically, enacting signaling cascades via the matching of chemicals such as neurotransmitters to receptors. Some neurotransmitters contribute to the mutual interactions between the gut microbiome and the host directly, their synthesis controlled by the microbial control of the neurotransmitter precursors. In addition to the classical hypothalamic–pituitary–adrenal axis and endocrine pathways (intestinal peptides and hormones), there is growing evidence that the metabolites (short-chain fatty acids, neurotransmitters, and their precursors) produced by bacteria affect levels of related metabolites in the brain via the blood circulation, meaning they play a role in regulating brain functions and cognition. Life experiences, genetics, and environmental factors intricately shape an individual’s gut composition, which in turn has profound implications for brain health. Understanding this gut-brain connection at a personal level allows us to gain valuable insights into our health and optimize our cognitive function.  

On a microbial level, brain health can be evaluated by observing the varying concentrations of microbes present in an individual's gut. Studies have found unique microbiome compositions linked to everything from Stress to Parkinson’s Disease. Jona’s analysis compares the patterns in your personal microbiome to these studies to see if your microbiome profile fits with these conditions. 

Although stress is common, the exact implications on the microbial level are relatively unknown. The biological cascade that accompanies heightened levels of cortisol observed in the body's stress response increases inflammation and triggers proliferation of bacteria linked to dysbiosis and permeability issues. Various types of stressors ranging from acute to chronic can change the gut microbiome in multiple regions and habitats – including within the lumen and mucosal lining of the gut. One novel study showed that most hostile couples had greater gut permeability than their less-hostile counterparts. In summary, the reshaping of the gut composition via stress hormones, inflammation and stress-induced nervous system issues causes the gut bacteria to release toxins, inflammatory cytokines and metabolites that can alter behaviors and mood.

The gut microbiome also plays a critical role in managing anxiety. Altered microbiome states can lead to inflammation and may contribute to anxiety. Research on the Influence of Microbiota on Mood and Mental Health shows that individuals with gastrointestinal issues, such as irritable bowel syndrome (IBS), often have heightened anxiety levels. Certain gut microbiomes can lead to altered production of neurotransmitters like serotonin and GABA which are essential for regulating mood and anxiety.

Surprisingly, your microbiome can even affect the way you think. There is clear evidence that the gut microbiota is linked to depression. When looking into the physiological factors affected by Major Depressive Disorder, studies have found an elevated abundance of Actinobacteria and diminished grey matter volume, which plays a significant role in all aspects of human life, including enabling individuals to control memory, emotions, and movement.  According to some research, depression may overtake heart failure as the most common disease in the world by 2030. Anxiety and depression can be classified as gut-brain axis disorders where positive gut microbiota alterations are being explored as a potential treatment. These alterations can be done by unique neurotransmitter regulation modification in the brain. When in a depressive state, signals in the form of cytokines, infectious substances and vagal sensory fibers are sent to the brain regarding the state of one's gut.

Research claims that symptoms of ADHD emerge from underlying deficiencies in neurocircuitry and, as we now know, interactions between neurotransmitters and receptors. Like a microbial biological clock, your gut undergoes changes throughout your life from childhood to adulthood, with its diversity gradually increasing. When looking at children with ADHD researchers observed that the gut might be maturing at a faster right, resembling a more adult-like composition. Through our understanding of the gut-brain axis, we can potentially deduce that these microbial changes are likely causing the brain to mature in different ways. Understanding what makes your microbial clock tick is important to optimizing gut function and employing preventative strategies against conditions like ADHD.  Jona’s analysis can provide you with the information to help you do so, in physiological situations where personalization and specificity matters most. 

There is evidence that is indicative of the fact that one's gut microbiota might be involved in migraine development. The biological cascade we observe in Migraines is: heightened stress levels, leading to negative changes in gut composition in which Calcitonin gene-related peptide (CGRP) is secreted, leading to the common symptoms of migraines, including sensitivity, stiffness and fatigue (for more on the connection between the GI tract and the gut microbiome, see here). Migraines are frequently accompanied by GI symptoms such as nausea, vomiting, diarrhea, or constipation. Changes in nervous system activity mediated by cytokines, hormones and transmitters contribute to both the development of migraines and GI disorders – tying the gut and the brain together. 

Similarly to its peers, Parkinson’s disease is also associated with gastrointestinal dysfunction, and symptoms of such can occur up to decades before official diagnosis. In patients with Parkinson’s disease, studies have observed a decrease in short-chain-fatty-acid producing bacteria (SCFA’s), which stimulate gut motility and host immunity, as well as metabolism. SCFA production has also been linked with reduced inflammation and positive metabolic outcomes. Going back to our neural superhighway connecting the gut and brain, the vagus nerve, a 2017 study found that the risk for Parkinson’s is decreased in people who have had their vagus nerve cut, showing a strong indication that degenerative material was transmitted through this nerve. The connection between gastrointestinal dysfunction and Parkinson’s disease highlights the significance of the gut-brain axis, with the integrity of the vagus nerve suggesting a critical pathway for disease progression, but also an avenue for symptom mitigation and disease improvement. It’s all about knowing where to look, and Jona can help you navigate that.