MHM Magazine

How can GUT BACTERIA be so powerful? Let's refresh on the anatomy of the small intestine. The small intestine lumen is lined by a velvety layer of villi. Each villi is covered by a single layer of epithelium consisting of different cell types. One significant cell type is the enteroendocrine cell which can communicate through synapses with the vagus nerve. Enteroendocrine cells with synapses are called neuropod cells which can sense mechanical, thermal and chemical stimuli such as nutrients in the gut lumen. Inside the neuropod cell , signals from the stimuli are converted to electrical impulses which propagate onto nerve connections directly with the vagus nerve, thereby directly linking the gut to the CNS. That chemical stimulus (nutrient) can travel from the gut lumen to the CNS within a few seconds. More about the gut microbiome The gut microbiome develops intrauterine. A healthy gut microbiome consists of a large variety of different bacteria. For optimal health we need a balance between healthy and unhealthy bacteria which means a small amount of unhealthy bacteria IS needed for good health. Food supplies nutrients which are metabolised by various enzyme reactions in the gut. The microbiome plays an important role in breaking down and absorbing important proteins from food. Some of these important proteins absorbed will serve as building blocks for essential neurotransmitters such as SEROTONIN, DOPAMINE, GABA etc. Research has shown that the following bacteria are involved in the synthesis of respective neurotransmitters: • Lactobacillus and bifidobacterium-the synthesis of GABA from monosodium glutamate • E. Coli, Bacillus and Saccharomyces - norephedrine synthesis. • Candida, streptococcus, Escherichia and enterococcus - serotonin synthesis. • Bacillus and Serratia-involved in dopamine synthesis. What causes gut dysbiosis/ disruption of the gut microbiome? • Physical stress -inflammation, pain • Mental stress - BOTH real and perceived trigger same response • Environmental stress-extreme temperatures • Nutrient deficiency or excess esp. excess of sugar • Alcohol use disorders • Excessive sedentary lifestyle • Lack of good quality sleep • Aging Any form of stress triggers overgrowth of some species and undergrowth of other species of bacteria in the gut, e.g. decrease in bacteroides and increase in clostridium species in the caecum, thereby triggering an immune response which results in inflammation at the gut. The inflammatory markers travel to the CNS via both: • The blood stream and • Change in protein/ neurotransmitters produced by the microbiome via the neuropod cells to the vagus nerve Is there hope? We CAN improve gut microbiome by several simple but consistently applied strategies: Stress management • Meditation • Mindfulness • Regular exercise: consistency is more important than intensity • Maintain a consistent diurnal eating pattern because the gut microbiome also follows some form of circadian pattern. Gut microbiomes differ from day to night. • Good quality and adequate sleep • Healthy and varied diet with fresh fruits and vegetables and healthy meats OR where this is not possible supplement the patients diet appropriately e.g. omega supplements or IMI vitamin B supplements. • Encourage prebiotic foods which are high in fibre • Encourage probiotic foods - such as plain natural or Greek yogurt. Where necessary- probiotic supplements may be used. • Small amounts of fermented foods are evidenced to help maintain a healthy microbiome. Vagal Nerve stimulation (VNS): There is novel treatment for treatment resistant depression which has recent FDA approval. A new hypothesis is the current from the chest electrode may trigger changes to the gut microbiome and thereby trigger important neurotransmitter proteins such as serotonin, dopamine, GABA to be produced relieving depressive symptoms. Early clinical trials show positive evidence for the use of VNS in treating: • ADHD • OCD • PTSD Autism spectrum disorders (ASD): Some evidence suggests that patients with ASD have high amounts of a certain bacterial molecule/by-product in the blood. Rodents with the same molecule displayed irritability, anxiety and brain activity similar to that seen in ASD patients. Parkinson's disease (PD): PD is characterised by tremors, muscle stiffness and unsteady gait believed to be caused by the mis- folding of a protein in the motor part of the brain. A new hypothesis that a particular strain of E. Coli in the microbiome is responsible for producing a mis- folded protein similar to that seen in PD. In a study, when the same strain of E. Coli was transferred into mice, the same misfolded protein was detected. After 2 months, the same mice displayed the neurological changes and symptoms common to PD. Overall there seems to be an increasing understanding of what the gut microbiome is and its function in the body. It’s likely that ongoing scientific research in this field will reveal stronger evidence for the role that the gut microbiome plays in important human behaviour such as mood, memory, cognitive function, and perhaps even motor function. New scientific wisdom in this field will enable better and holistic management of mental well-being. In the meantime, there can only be benefits to obtaining a thorough dietary and lifestyle history for all patients including those presenting with mental illness. References available on request. MHM | 2024 | Volume 11 | Issue 2 | THE GUT- BRAIN AXIS: Are we being controlled by our GUT instinct? MHM Issue 2 | 2024 | MENTAL HEALTH MATTERS | 15 MHM