Oral and Gut Bacteria Linked to Dementia Among Parkinson’s Patients: Study

New Delhi: A recent study by researchers at King’s College London has revealed that bacteria in the mouth and gut may play a critical role in the progression of cognitive decline in individuals with Parkinson’s disease. Published in the journal Gut Microbes, the study offers new insights into how disruptions in the gut-brain axis could contribute to one of the most distressing symptoms of Parkinson’s—dementia.

Parkinson’s disease is a progressive neurological disorder, and while early diagnosis remains a significant challenge, this research suggests that changes in gut and oral microbiomes might serve as early indicators. The study focused on two groups of Parkinson’s patients—those with mild cognitive impairment and those with dementia—and compared their bacterial profiles to those of healthy individuals.

Researchers analysed 228 samples of stool and saliva to understand microbial composition. They found significant differences in both the types and functions of bacteria between Parkinson’s patients and healthy participants. Notably, individuals with cognitive impairment had higher levels of harmful bacteria in their gut, many of which appeared to originate from the mouth, a process described as “oral-gut translocation.”

These oral bacteria, once in the gut, were found to release harmful molecules called virulence factors. These toxins can damage the gut lining, trigger inflammation, and may even influence the brain, potentially worsening neurological symptoms.

Dr. Saeed Shoaie, lead investigator and group leader at the Quantitative Systems Biology Lab, explained that disruptions in the gut-brain communication could lead to immune responses and inflammation that accelerate neuronal damage. Using artificial intelligence, the team was able to link specific bacterial toxins to cognitive decline in Parkinson’s patients, identifying them as potential biomarkers for dementia risk.

Dr. Frederick Clasen, co-author of the study, emphasised that while it's not yet clear whether the bacteria are a cause or consequence of disease progression, they appear to have an active role in symptom development. He also noted that these findings could guide future therapeutic strategies aimed at altering the gut environment to slow or prevent cognitive decline.

The research also underscores the importance of oral hygiene and proper nutrition in managing Parkinson’s, especially in advanced stages of the disease.