New Delhi: Bacteria in the mouth and digestive tract could play a key role in the progression of cognitive decline in individuals with Parkinson’s disease, according to recent research.
The study found that particular changes in the gut microbiome are linked to the progression from mild cognitive issues to dementia—a frequent and troubling symptom of Parkinson’s. Since early-stage Parkinson’s can be challenging to diagnose, these microbial changes may serve as early indicators of the disease, according to researchers from King’s College London.
Such early detection could give healthcare providers a valuable window to intervene before the condition worsens.
“There is a growing connection between the microbial communities in the gut and mouth and the development of neurodegenerative disorders. Disruptions in the gut-brain communication pathway may lead to immune and inflammatory responses that damage neurons,” said Dr. Saeed Shoaie, who leads the Quantitative Systems Biology Lab at King’s College London.
The research, published in the journal Gut Microbes, examined bacterial samples from the stool and saliva of 228 individuals.
Participants included two groups of Parkinson’s patients: those experiencing mild cognitive impairment and those diagnosed with dementia, reflecting different disease stages. These groups were compared to a healthy control group with no history of Parkinson’s.
The analysis revealed distinct differences in both the types and functions of bacteria present in each group. In individuals with cognitive impairment, the gut showed a higher presence of harmful bacteria, many of which appear to originate from the mouth.
This phenomenon, known as “oral-gut translocation,” describes the migration of oral bacteria to the gut—an environment where they are not typically found.
Once there, these bacteria produce specific toxins called virulence factors. These compounds can damage intestinal tissue, trigger inflammation, and may have an impact on brain health.
The findings underline the importance of maintaining good oral hygiene and nutrition, particularly for people living with Parkinson’s disease as it progresses.