As we discussed last week, microbiota strongly influences brain response through stimulation/inhibition of neurotransmitter release.
Following the same line we are going to talk about the importance of the intestinal microbiota and a good state of mental health.
There are 5 pathways of connection between the microbiota and the brain:
- Neurons of the central nervous system
- Neuroendocrine-hypothalamic-pituitary-adrenal axis
- Gut immune system
- Neurotransmitters and neuronal regulators
- Mucosal-intestinal and hematoencephalic barriers
The main modulatory pathway through which signals reach the brain from the intestine is through the vagus nerve.
An altered microbiota and dysbiosis affect both the communication of signals through the vagus nerve and the release of neurotransmitters.. This has a significant impact on the appearance of psychiatric manifestations.
Vagus nerve stimulation can help treat psychological disorders, including episodes of severe depression. including episodes of severe depression.
This stimulation of the vagus nerve can take place through the administration of probiotics and prebiotics. (minimum for 4 weeks) leading to a decrease in brain regions involved in the emotional processing of negative/sad stimuli.
People who suffer from or are at increased risk for mood disorders process negative and positive stimuli in a biased manner (these biases depend on the specific nature of the stimulus).
Emotion bias represents a key marker of depression and anxiety.
Consumption of prebiotics affects emotional attention and participants show decreased cognitive reactivity to sad mood. less bias towards negative information and decreased cognitive reactivity to sad mood.
In contrast, antibiotic use, which alters the microbiota in a negative way, is related to a greater bias toward sadness.
On the other hand, bacteria in the digestive system are involved in the synthesis of serotonin. (happiness hormone). So, a deregulation of these bacteria results in a lower synthesis of serotonin and, therefore, a lower state of happiness and well-being.
Maintaining a healthy and diverse microbiota through a healthy lifestyle and proper nutrition can prevent the onset of psychological disorders.