Before we dive into these findings, let’s cover the current state of Parkinson’s research, preceding this study.

The most common suspected cause of Parkinson’s disease is a pathological pattern of Lewy body (LB) protein deposition. These depositions, researchers say, mainly consist of misfolded α-synuclein—a presynaptic neuronal protein that is linked genetically and neuropathologically to Parkinson’s disease1. 

Interestingly, the misfolded α-synuclein has not only been found in the central nervous system but also in the vagus nerve and the enteric nervous system (ENS)—the latter located within the walls of the GI tract, 2extending from the esophagus to the anal canal, in people with Parkinson’s disease.

The new study, published in BMJ Journals set out to explore the possibility of Parkinson’s disease originating in the gut, based on the fact that misfolded proteins have been found in the GI tract and esophagus.

In order to study this, researchers looked for Parkinson’s patients who had digestive symptoms before being diagnosed with the brain disorder.

The researchers analyzed a combination of case-control studies of 24,624 Parkinson’s patients and a cohort study utilizing a US-based nationwide medical record network. They looked for a broad range of both GI symptoms and GI diagnoses that appeared before Parkinson’s diagnoses.