Why Parkinson’s research focuses on the gut

Why Parkinson's research focuses on the gut

Gut Health and Parkinson’s Disease: Exploring the Connection

Parkinson’s disease is a debilitating neurological condition that affects millions of people globally. Its symptoms can range from mobility issues and muscle control problems to mood changes, gastrointestinal disturbances, and cognitive decline. While there is currently no cure for Parkinson’s, researchers are continuously seeking a better understanding of the disease to develop improved treatments. One area of focus in recent studies is the connection between gut health and Parkinson’s disease. This article will delve into why researchers are investigating the gut-brain axis, how the gut microbiome differs in Parkinson’s patients, potential mechanisms involved, and the role of exercise and diet in managing the condition.

Unraveling the Gut-Brain Axis

The gut-brain axis is a bidirectional communication pathway between the brain and the gut. Over the past few years, evidence has emerged indicating that this connection plays a crucial role in various brain-related health conditions, including dementia and depression. Although less apparent in some diseases, the gut-brain link becomes clearer in Parkinson’s, where gastrointestinal symptoms like constipation often accompany the neurological impairments.

The Braak hypothesis, a perspective on Parkinson’s disease, suggests that an unknown pathogen might reach the brain via two routes, one involving the gut. According to this hypothesis, the vagus nerve, a cranial nerve that connects the brain to the intestines, could serve as a pathway for certain pathogens to trigger Parkinson’s. While the thought of exploring the gut to understand Parkinson’s disease may seem surprising, the Braak hypothesis provides an intriguing lens through which researchers can assess potential mechanisms involved.

The Unique Gut Microbiome in Parkinson’s

Recent studies, including a paper published in Nature Communications in November 2022, have shown that individuals with Parkinson’s disease have distinct gut microbiomes characterized by dysbiosis, an imbalance between beneficial and harmful bacteria. According to these studies, around 30% of the gut bacteria in people with Parkinson’s differs from that of individuals without the disease.

The dysbiosis observed in Parkinson’s patients manifests in reduced amounts of gut-friendly bacteria, such as short-chain fatty acid producers, while pathogenic bacteria like Escherichia coli are more abundant. Notably, the study conducted by Dr. Ayse Demirkan and her colleagues found significantly elevated levels of infection-causing bacteria like Bifidobacterium dentium in the gut of people with Parkinson’s disease.

Further research has implicated Desulfovibrio bacteria, which produce hydrogen sulfide and may lead to inflammation, in Parkinson’s disease. Another study identified an overabundance of Desulfovibrio in individuals with REM sleep behavior disorder, a condition associated with a higher risk of developing Parkinson’s.

Potential Mechanisms at Play

If gut bacteria indeed contribute to Parkinson’s disease, it raises questions about the mechanisms mediating their impact on neurological health. One hypothesis proposed by studies on the gut-brain link in Parkinson’s disease suggests that systemic inflammation may play a role. Pro-inflammatory bacteria that are overabundant in Parkinson’s have the ability to trigger inflammation. Evidence from research on immunosuppressant medication also indicates a lower risk of Parkinson’s disease, suggesting that similar medications may aid in managing the condition.

Furthermore, chronic brain inflammation is a significant aspect of Parkinson’s disease, and the relationship between systemic inflammation and brain inflammation could contribute to disease progression. Inflammatory conditions like inflammatory bowel disease (IBD) have also been associated with a higher risk of Parkinson’s, as suggested by a Danish study in 2018.

Although the potential link between inflammation, gut bacteria, and Parkinson’s is promising, further research is needed to confirm and better understand these mechanisms.

Exploring the Diet Connection

Considering the role of gut bacteria in Parkinson’s disease, it is tempting to speculate that diet could help modulate gut dysbiosis and potentially alleviate symptoms. While there are some dietary recommendations and nutritional supplements that may provide relief for certain individuals, the impact of diet on the disease’s progression remains unclear.

Research suggests that diets rich in flavonoids, natural pigments found in many fruits, may be linked to a lower risk of mortality in Parkinson’s. Additionally, a protein called “parvalbumin,” found in various fish, has been proposed as a potential preventive measure against Parkinson’s by preventing the aggregation of alpha-synuclein in the brain.

However, caution is necessary when considering diet and supplements for regulating gut bacteria in Parkinson’s. Personal differences in risk factors and disease manifestations make it challenging to provide general recommendations. Increased sugar consumption has been linked to issues, but intervention studies and finalized research are necessary to draw definitive conclusions. Individual factors and lifelong exposure to different elements make it difficult to provide specific dietary advice.

The Power of Exercise in Parkinson’s Management

Exercise has emerged as an effective strategy for managing Parkinson’s disease. A study published in Neurology in 2022 suggests that regular, moderate-to-vigorous exercise can slow down the progression of Parkinson’s in the early stages. Another study from 2017 recommends at least 2 and a half hours of exercise per week to improve mobility and slow down disease progression.

Dr. Demirkan highlights the positive impact of exercise on shaping the brain and body. Exercise-induced heat stress may impact the gut microbiome by potentially suppressing some bacteria and allowing others to thrive. A Cochrane review supports the notion that all forms of exercise can improve the quality of life for people living with Parkinson’s disease. Aqua-based training and endurance training have shown particular benefits in managing motor symptoms and overall life quality.

Exercise also plays a significant role in mental well-being. People with Parkinson’s, like Gary Shaughnessy, who has taken on challenging physical activities to raise funds for Parkinson’s research, find that exercise helps them momentarily forget about their condition. The mental attitude towards the disease greatly influences its management, where focusing on what can be achieved at any given moment is key.


Research into the connection between gut health and Parkinson’s disease has shed light on the impact of gut bacteria and inflammation on the neurological condition. While our understanding of this relationship is still evolving, studying the gut microbiome has provided valuable insights into dysbiosis and potential mechanisms involved in Parkinson’s disease. Additionally, exercise has emerged as a powerful tool for managing symptoms and improving overall well-being.

As researchers continue to unravel the mysteries of Parkinson’s disease, investigations into the gut-brain axis remain promising avenues for developing better treatments and supportive interventions. While a cure may still be on the horizon, a comprehensive approach that considers the role of gut health, diet, exercise, and other factors holds potential in improving the lives of those living with Parkinson’s.