Parkinson’s and the gut

Parkinson’s is often preceded by problems in the gut, and changes in the nervous system surrounding the gut often accompany the condition. Additionally, the gut microbiome is emerging as an important regulator of neurodegeneration, and accumulating evidence has linked gut microbes to Parkinson’s symptoms and biology.

Emerging evidence suggests that our immune system has a role beyond simply fighting infections. Immune cells in the gut, for example, are able to send signals to the gut’s own nervous system, and these signals are then relayed to the brain via the vagus nerve. This nerve is an essential part of the gut-brain axis, a two-way communication pathway that connects the digestive system to the brain, allowing information to flow in both directions.

Furthermore, scientists also believe that the gut microbiome – the collection of microorganisms including bacteria, fungi and viruses that naturally live in our digestive tract – might influence the brain through their interactions with the vagus nerve.

How could the gut be connected to Parkinson’s?

In Parkinson’s, early symptoms can include gastrointestinal issues like constipation, which can sometimes precede the onset of the condition by decades. Some people with Parkinson’s also exhibit differences in their gut microbiomes compared to those without the condition, although researchers are still working to understand the cause of these differences.

Evidence for the vagus nerve connection in Parkinson’s stems from research on the protein alpha-synuclein, known to misfold and aggregate in the brains of people with Parkinson’s. When misfolded alpha-synuclein has been injected into the gut in laboratory models of Parkinson’s, it travels through the vagus nerve to the brain.

This gut-brain connection may also involve chemical messages carried by small molecules called metabolites, which the gut microbiome produces to break down food, drugs, and other compounds. Research has shown that certain metabolites can travel from the gut to the brain, where they may influence mood, behaviour, and immune regulation within the brain.

These findings highlight the complex relationship between the gut, immune system, and brain, suggesting that the gut microbiome and its interactions with the vagus nerve could play a key role in the development and progression of Parkinson’s.

Watch our 2024 webinar discussing the relationship between the gut, nutrition and Parkinson’s, and the emerging understanding of how the gut-brain connection has a role in Parkinson’s progression.