Obesity has reached epidemic proportions in Australia. Two out of three adults are either overweight or obese. There is a high prevalence of mood disturbances with overweight and obesity which can be linked to the gut-brain axis and the microbiome.
The typical Western diet of highly refined carbohydrates, sugar and fats and behaviours including high alcohol intake, low exercise, and a sedentary lifestyle all contribute to dysbiosis. Dysbiosis is an imbalance of good and bad bacteria in the body. Dysbiosis contributes to changes in gut-brain signalling and increased inflammation.
The gut-brain axis transfers information from hormones in the gut to the central nervous system, which relays these messages to the brain. Therefore, the gut microbiome can influence the gut-brain axis and alter brain messages through neurotransmitters.
These neurotransmitters can contribute to the development of obesity and also mood disturbances that can drive individuals to eat more or increase high-energy foods. The microbiome can signal to increase appetite, rewire reward messages and energy balance.
Changes in the microbiome can also affect neurotransmitters, leading to increased anxiety and stress. Stress can make individuals seek food as a reward, leading to overconsumption, especially of energy-dense foods. Stress also leads to fat accumulation around the abdomen through high cortisol (the stress hormone) and insulin resistance. Insulin resistance increases sugar in the body, leading to a higher deposition of fat and is a precursor to diabetes.
Dysbiosis can also increase inflammation through bad bacteria, increasing fatty acids and insulin resistance. An increase in fatty acids and inflammation can influence signalling in the brain, leading to anxiety and depression. Hence, it is a vicious cycle.
Natural medicines that can restore the microbiome and aid proper gut functioning are probiotics, prebiotics, gut barrier supplements and nutriceuticals to heal the gut's mucosal lining. Supplements, herbs and a healthy diet can also aid in mood regulation, lowering inflammation and regulation of blood glucose to aid overweight or obese individuals.