A conversation about mental health currently dominates all social media platforms; the issue affects 19% of the adult and 46% of the teenage population. Drawing people’s attention towards its importance and witnessing an incline in research on the interactions between the human brain, the gastrointestinal tract, the bacteria resident in the gastrointestinal tract, and their bidirectional relationship: the brain-gut– microbiome axis.
The human gut contains 1013–1014 microorganisms, 100 times more genes than our genome, weighing about 1 kg in the adult. Bidirectional communication exists between the brain and the gut, through multiple pathways of neural (Vagus nerve) and/or spinal cord, endocrine (HPA, axis), immune (cytokines), and metabolic. It is considered to be a ‘second brain’, for it is highly networked and functional. It is the main organ to flaunt its autonomous sensory system, a system of 100 million neurones implanted in the gut lining and 100 trillion organisms colonising the GI tract that are basic to wellbeing.
Microorganisms which call the human gut home are a multifarious and inimitable mix of bacterial species, partially dictated by hereditary traits and to some extent by the makeup of microorganisms living in and on people around, medical practices and exposure. The food we consume, the day-to-day stress represent aspects of lifestyle that have the potential to influence the microbiota. Microbes residing in our gut, symbiotic or pathobionts, are capable of producing neurochemicals that in turn aid in normal functioning and preventing certain neurodegenerative diseases.
When analyses of gut microbiomes of individuals struggling with psychiatric or neurological disorders were carried out, great differences were seen concerning the composition of the microbiome. It has been found that any disturbance or decline to the normal, healthy balance of microorganisms within the gut can be detrimental for immune relationships, neuroendocrine and gastrointestinal systems.
Neurotransmitters, γ-aminobutyric acid (GABA), Serotonin, Dopamine (DA), Acetylcholine (ACh) are secreted by the microbes, which are used by the cerebrum in controlling essential physiological functions such as cognition, sleep, motor control, and reward and reinforcement behaviour. Bacteria such as Lactobacillus species are found to yield acetylcholine and GABA; Bifidobacterium is a known producer of GABA; Escherichia secretes norepinephrine, serotonin and dopamine, Streptococcus & Enterococcus are producers of serotonin and Bacillus yields norepinephrine and dopamine.
Faulty neurotransmission leads to several pathological conditions, such as hyperprolactinaemia, depression, autism spectrum disorder, schizophrenia, ADHD and Parkinson’s disease. These conditions rely on heavy doses of prescribed medications (antidepressants and antipsychotics) causing uncomfortable side effects leading to non-compliance by the patients.8 An alternative on the basis of accumulating scientific evidence could be a dietary supplementation of probiotic strains that replenish the gut and synthesise DA in moderation along with other essential metabolites that are a requirement of the body.
When Hippocrates coined “let food be thy medicine” over 2000 years ago, it revolutionised modern approach on nutritional research which has been at the core of medical, economic, cultural and social research. Health organisations all over the globe are endeavouring to achieve proper standards for a healthy diet which is the perfect blend of micro and macronutrients, as diet has proven to be a pivotal determinant of microbial composition in the gut. Augmenting gut microbiome employing probiotics, prebiotics or nutritional change, can largely impact to enhance mood and alleviate anxiety.
Microbiome-focused therapy is becoming more intriguing, as people are gaining an in-depth understanding that everyone has a unique gastrointestinal fingerprint and that treatment might more often than not be tailor-made for the needs of that individual.
Now more than ever it is essential to shift perspectives on microorganisms and taking their help in improving health and finding long-lasting treatments for mental illness. They have been evolving for years now while surviving in the human gut and it is very likely that they hold the key for a breakthrough for human health (digestive, mental, cardiac and immune).
The cross-talk between the Gut-microbiome and the brain via the Brain-gut axis is crucial to neurodevelopment and a promising therapeutic approach as an alternative to mind-altering drug treatments.
I undertook an undergraduate research project, focusing on the same area. Isolated Lactobacillus and Saccharomyces from Yakult and homemade curd. Following purification, they were bulk grown anaerobically with amino acid, tyrosine, a precursor for DA. On ultra-sonication and centrifugation, a crude dopamine extract obtained was quantitatively and qualitatively assessed against a standard solution of dopamine hydrochloride via a UV Spectrophotometer: at λ max of 300nm, Lactobacillus spp yielded the highest quantity of dopamine (48mg/ml) and using Thin-Layer Chromatography: yellow bands on the TLC plate indicated presence of dopamine.