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A new study suggests that changes in gut bacteria may help predict a person’s risk of developing Parkinson’s disease years before symptoms appear. Researchers from University College London (UCL) led an international team that analyzed the gut microbiomes of 271 people with Parkinson’s, alongside groups carrying a key genetic risk and healthy controls in the United Kingdom and Italy. Their findings, published in Nature Medicine, show that about a quarter of the gut’s bacterial species differ between people with Parkinson’s and those without the disease, with distinct patterns also present in those genetically at risk but not yet symptomatic.
According to UCL researchers, people with Parkinson’s have a unique gut bacteria profile, and healthy individuals carrying a variant of the GBA1 gene showed intermediate gut changes. This suggests that gut bacteria may serve as an early warning sign for Parkinson’s, appearing before traditional movement symptoms develop.
The research team, led by Professor Anthony Schapira at UCL’s Queen Square Institute of Neurology, explained that identifying these microbial changes could allow for earlier intervention. “For the first time we identify bacteria in the gut of people with Parkinson’s that can also be found in those with a genetic risk for the disease, but before they develop symptoms,” Schapira said. He added that modifying the gut microbiome, potentially through diet or medication, might reduce a person’s risk for Parkinson’s.
The study compared bacteria from people with Parkinson’s, GBA1 gene carriers without symptoms, and healthy controls, using clinical and stool sample data. They found that 176 bacterial species (over 25% of the gut microbiome) differed between Parkinson’s patients and healthy controls, with 142 of these species also showing changes in the at-risk group. The researchers noted that people with more advanced Parkinson’s had greater disruptions in gut bacteria than those in earlier stages, a finding echoed in similar studies worldwide, including in the United States, Korea, and Turkey.
These gut changes were most pronounced in individuals with more severe symptoms and those in the early phase of the disease. The study also found that a balanced, varied diet was linked to a healthier gut microbiome and lower apparent risk for Parkinson’s, suggesting diet modification could play a role in prevention.
The UCL team is continuing research into gut health and Parkinson’s, including clinical trials targeting the gut’s immune system and testing new therapies. This work could eventually lead to earlier detection methods and preventive strategies for those at risk of Parkinson’s disease.