Parkinson’s disease (PD) is a condition in which parts of the brain become progressively damaged over many years leading to stiff muscles, slow movement, shaking and some psychological problems. Commonly, constipation occurs before PD, and there may be some changes in the gut of people with this condition as the protein that causes PD has been found both in the brain and the gut of individuals with the disease. The gut in humans has a variety of helpful bacteria whose balance and harmony can change depending on our diet, environmental circumstances and genes. The imbalance in the microbial bacteria gut is known as Dysbiosis. The gut and the brain impact one another through substances known as hormones and pathways such as nerves (fibres that transmit impulses and information in our body). There is literature suggesting that our gut environment may be involved in PD. It is therefore considered whether inflammation and immune responses in the gut may spread to the brain and cause the start of movement problems in PD.
This paper analyses various papers that have been published to investigate whether there is a connection between our gut environment, and whether it may be a factor in causing PD. There are many studies, mostly carried out on animals on how substances which are known to cause disease in PD have been shown to be present in the gut as well. Potentially, this could indicate that changes in the gut system may spread or cause changes in the brain. Further research is needed to understand the exact relationship here as there have been some studies with contradicting results. An important study to note is one that surgically removed the structure that communicates with the brain and gut directly to see if this would change the outcomes. Although, the studies in animals have shown positive results, when attempted on humans it has been less successful. This is the case for many potential studies in this area. In conclusion this is an important area to investigate further, as drugs could be used to alter the gut environment and thus affect disease progression in PD.