The diversity and health of our gut microbes plays a significant role in our mental health and our body’s ability to fight infection, manage moods, downregulate the production of the stress hormone, cortisol and much more [36, 37]. Gut health and homeostasis (balance) is disrupted by our lifestyle, unhealthy eating styles, and stress [38]. Put simply, the health of our stomach and what we put in it affects the functioning of our brain [36, 37]. For some time, the gut has been called the “second brain” because its network and interconnectivity is more complex and influential than previously known. Through three communication pathways (the nervous system, endocrine system and immune system) the “gut-brain” pathway constantly sends information from the digestive tract directly to the brain (Brian) to maintain homeostasis [35. 36].

In general we begin to suffer when the good/bad bacteria percentage ration falls below 85/15. When this ration is disturbed a condition known as leaky gut can develop over time which is linked to the development of autoimmune disorders such as rheumatoid arthritis, lupus, Hashimoto’s and others. When pathogens creep up, due to illnesses, aging, stress and poor nutrition, dysbiosis takes place [109]. In this state, we’re more vulnerable to infections and disease, which can pass directly into our brain. It’s an odd thought, but the gut microbiome is among the larger organs in our body [36, 37].

Diets high in saturated fats (cholesterol) affect gut functioning resulting in intestinal inflammation that in turn, alters the blood brain barrier, leading to the onset of neuroinflammation [38]. This disruption in communication between our gut and host systems leads to the development of metabolic disorders, diabetes mellitus, and autoimmune disorders. This disruption also contributes to the development of neuropsychiatric disorders, including autism, anxiety, ADD/ADHD, major depressive disorders and dementia [38]. High cholesterol has been positively linked as a significant factor for the onset of Alzheimer’s.

Ghrelin is a gut peptide released in response to nutrients that is directly correlated with activation of brain regions that control food intake regulation, emotional circuitry, and reward responses]. Stress that elevates glucocorticoid secretion will elevate circulating ghrelin levels that in turn lead to increased food intake. Leptin is another important factor in the “gut-brain” pathway because it signals fullness and reduces appetite [38]. When our brain loses sensitivity to leptin signaling, we tend to eat more than we need because the gut-brain messaging that we’ve consumed “enough” becomes unreliable.