Gut Microbiome Alterations May Signal Progression of Parkinson's Disease

Recent research conducted by experts at King's College London reveals that changes in the gut and oral microbiota of Parkinson's disease patients may serve as early indicators of cognitive decline associated with the condition. The study, published in the journal *Gut Microbes* on June 9, 2025, highlights the potential of utilizing these microbial shifts as biomarkers for identifying patients at greater risk of developing dementia, a common complication of Parkinson's disease.

Parkinson's disease is a progressive neurodegenerative disorder characterized by a variety of symptoms, including tremors, depression, balance issues, sleep disturbances, and cognitive impairment. According to the Alzheimer’s Society, approximately one-third of individuals diagnosed with Parkinson’s eventually experience dementia (Alzheimer’s Society, 2023).

Dr. Saeed Shoaie, the group leader of the Quantitative Systems Biology (QTS) lab at King’s College London and co-author of the study, emphasizes the significance of gut and oral bacteria in relation to neurodegenerative diseases. "Disruptions in the gut-brain axis could trigger inflammation and immune responses that contribute to neuronal damage," he asserted. This connection was further underscored by findings that identified the bacterium *Porphyromonas gingivalis*, commonly associated with gum disease, as a possible contributor to Alzheimer’s disease (Shoaie, et al., 2025).

The research team analyzed 228 saliva and stool samples from 41 patients with Parkinson's and mild cognitive impairment, 47 patients with Parkinson's and dementia, and 26 healthy controls. The results indicated that individuals with mild cognitive impairment exhibited a higher prevalence of harmful bacteria, many of which likely originated from the oral cavity. These bacteria produce toxins that can damage gut tissue, promote inflammation, and potentially affect cognitive functions (King's College London, 2025).

Using artificial intelligence (AI), researchers were able to identify specific bacterial species and functions that traditional testing methods might overlook. This advanced analysis linked certain toxins to cognitive decline, further suggesting that maintaining oral and gut health may be crucial for managing neurodegenerative processes in Parkinson's patients (Clasen, 2025).

Dr. Frederick Clasen, a research associate at the QTS lab, noted the dual nature of the relationship between gut bacteria and cognitive decline. "We don’t yet know if the bacteria are causing the cognitive decline or if changes in the body due to Parkinson’s allow these bacteria to flourish. However, our findings suggest they may play an active role in worsening symptoms," he explained (Clasen, 2025).

The implications of this research are significant, as the identification of these microbial markers could lead to the development of targeted treatments. Dr. Clasen further stated, "These toxins could serve as biological markers for identifying patients at higher risk of dementia in Parkinson's, and may also become targets for new therapies aimed at altering the gut environment to protect brain function" (Clasen, 2025).

The study's findings also highlight the importance of regular oral hygiene and a balanced diet for individuals with Parkinson's, as neglecting these aspects can exacerbate symptoms and overall disease management. By promoting a healthy microbiome through consistent oral care and nutritional interventions, caregivers and healthcare providers may enhance the quality of life for patients suffering from this debilitating disease (Shoaie, 2025).

In conclusion, as the research underscores the interconnectedness of gut health and neurological function, it becomes increasingly evident that further exploration of the gut-brain axis could yield vital insights into the progression of Parkinson’s disease and pave the way for innovative treatment strategies. The ongoing investigation into this relationship will be crucial in addressing the needs of the growing population affected by neurodegenerative diseases worldwide.