write 1600 words essay from this outline:
ESSAY PLAN
Title: The Gut Microbiome: A Key Player in Mental Health and Well-Being
I. Main idea (Thesis Statement):
The gut microbiome forms one important constituent of the gut-brain axis, and bad gut health will be disastrous for psychological well-being.
II. Paragraph 1 - The Gut-Brain Axis: A Two-Way Street
A. Direct nerve signaling between gut and brain
1- The vagus nerve may detect the metabolites secreted from the gut microbiota, which conveys a signal of gut status to the brain for an integrated response for maintaining homeostasis. (Bonaz,2018. p1)
2- Recent data show that enteroendocrine cells in the gut are also capable of forming synapses with vagal afferents, pointing to a more direct neural circuit for the transmission of sensory information about nutrient intake. (Kaelberer, 2018. P2)
B. Gut bacteria themselves produce neurotransmitter-like chemicals, i.e. serotonin (Enders, 2014, p. 121)

Modulate mood, cognition, and behavior (Enders, 2015, p. 60)
Changes in the gut microbiota were proven to cause changes in brain functions and behavior. For instance, germ-free mice depicted higher locomotor activity with lower anxiety as compared to conventionally colonized animals. It was thus concluded that normal colonization of gut microbiota is required for the proper development and maintenance of the brain and behavior regulation (Diaz, 2011 P4074)
C. Immune modulation by Gut microbes affects brain
1- Gut microbiota are among the immune responses that contribute to brain health. They make a contribution to the integrity of the blood-brain barrier that is quite necessary for protection against most pathogens, therefore preserving neurological function (Braniste. 2014. P3).
III. Paragraph 2 - Gut Dysbiosis: A Recipe for Mental Distress, changes in gut bacteria may impact mood disorders, depression, and anxiety.
A. Several diseases are characterized by a reduced abundance of gut microbiome
The gut microbiome has an important role in the production of various neuroactive compounds, both SCFAs and neurotransmitters. The disturbed microbiome could be unable to continue this process; therefore, it may potentially lead to or worsen psychiatric conditions. (de Vos, 2022 P.1024)
Various psychiatric conditions have been related to gut microbiota composition, ranging from autism spectrum disorders, schizophrenia, and neurodegenerative diseases such as Alzheimer's and Parkinson's. Gut microbiota has been seen altered in such conditions, pointing towards the protective role of a healthy microbiome against such ailments. (Cryan, 2019, P1877)
B. More Susceptibility to Chronic Diseases
Metabolic disorders could be the result of an imbalanced gut microbiome, like obesity and type 2 diabetes through impaired glucose metabolism and inflammation. Indeed, according to studies, dysbiosis is associated with higher levels of systemic inflammation, which in turn easily deteriorates chronic diseases (Zhang, 2022 P.3)
IV. Paragraph 3 - Gut Nurturing for a Healthy Mind
A. Probiotics can restore healthy microbial balance
Prebiotics encourage the good bacteria, hence decreased amount of toxins generated within the gut. (Enders, 2015, p. 216)
B. Antibiotics can cause significant changes in our gut flora.
Our microbe collection becomes less diverse and the capabilities of the bacteria in it may shift. Changes include the amount of cholesterol they can absorb, their ability to manufacture vitamins-like skin-friendly vitamin H-and the type of foodstuffs they can help us digest. (Enders, 2014, p. 199)
C. Diet is one of the best choices for health
Different types of diet have been associated with different impacts on the composition of the gut microbiota (Cryan, 2019, P1935)
The beneficial effects of Mediterranean diet are mediated by its anti-inflammatory potential but also bring about marked changes at the level of gut microbiota - increasing the abundance of phylum Bacteroidetes and Clostridium, while reducing the abundance of Proteobacteria and Firmicutes phyla (Cryan, 2019, P1935).
V. Conclusion
The gut and the brain are closely related; thus, the state of our gut microbiome is deeply connected. Negligence of the gut microbiome is capable of carrying heavy repercussions in mental health because of the extensively delicate lines of communication between them.