THE LINK BETWEEN THE GUT AND DEPRESSION: A SYSTEMATIC REVIEW OF THE MECHANISMS INVOLVED IN THE GUT-BRAIN AXIS

Abstract

The link between the gut and depression has been the subject of study and research over the past few years. This systematic review aims to analyze the mechanisms involved in the gut-brain axis and their relationship with the occurrence of depression. The intestine is considered a "second brain" due to its complex network of neurons, known as the enteric nervous system. This network is involved in controlling basic intestinal functions such as digestion, but it also plays an important role in regulating mood and behavior. Recent studies have shown that there are several factors that can influence communication between the intestine and the brain and, consequently, affect an individual's mental state. One of these factors is the intestinal microbiota, that is, the bacteria that inhabit the intestine. Changes in the composition of this microbiota have been associated with depression, due to their ability to modulate the production of neurotransmitters and inflammatory substances. Furthermore, stress has been identified as a key mediator in the link between the gut and depression. Chronic stress can lead to changes in intestinal permeability, causing toxins and bacteria to leak into the bloodstream, triggering an inflammatory response that can negatively affect brain function. Another mechanism involved in the gut-brain axis is the production of neurotransmitters in the intestine. Studies have shown that the intestine is capable of producing neurotransmitters, such as serotonin, which play a crucial role in regulating mood. Changes in the production or absorption of these neurotransmitters may contribute to the onset of depression. In conclusion, this systematic review highlights the importance of the relationship between the intestine and depression, highlighting the mechanisms involved in the intestine-brain axis. Understanding these mechanisms may open new avenues for developing more effective therapeutic strategies for treating depression.