Have you ever had an “Aha!” moment? In science, these moments happen all the time. Old ideas are refreshed, and new perspectives pave the road to medical discovery. In fact, research concerning the prevention and treatment of Parkinson’s disease (PD) is moving in the wake of such an “Aha!” moment. The human microbiome, identified as a driving force behind health, is now considered a key player in the pathology of PD. The microbiome is comprised of all of the bacteria that live in your gut. By taking a closer look at the interconnectedness of PD and the microbiome, we see a hopeful future that explores the use of probiotic therapy to manage and heal a common neurodegenerative disorder. 
Take a moment and think about your experience with PD. What comes to mind? Has your gait turned into a shuffle? Do you have a tremor? Maybe you simply feel a bit stiff and off-balance. While motor symptoms are hallmarks of advanced PD, a slue of non-motor symptoms may appear 10 years prior to shaky, slow, and stiff movements. Among the early symptoms of PD are gastrointestinal disturbances that tend to worsen as the disease progresses. Although the percentage of PD patients who experience constipation varies, researchers Jost and Schimrigk at Saarland University in Germany found that constipation may affect up to 80% of PD patients. 
While gastrointestinal disturbances may seem marginally important, the gut’s involvement in PD demands attention. The human gut is a complex system that influences the body’s ability to absorb nutrients, fight pathogens, and impact brain function. With over 100 trillion microorganisms living in your gut, it’s no surprise that your microbiome has a big impact on health. The microbiota, which vary in composition and function as determined by genetics and the environment, may influence the motor symptoms and even non-motor symptoms you’re experiencing. Research shows that the enteric nervous system, known as the little brain of the gut, communicates the inner workings of the microbiome to the central nervous system via the vagus nerve. The gut microbiome may even influence the secretion of α-synuclein, a protein capable of causing mitochondrial dysfunction and the loss of dopaminergic neurons. 
It is difficult to know if an altered microbiome is a cause or consequence of PD; however, research does confirm a unique bacteria composition in PD patients. When examining the bacteria in PD patients compared to healthy individuals, Scheperjans et al. discovered a positive association between Enterobacteriaceae abundance and postural instability and gait difficulty. Additionally, PD patients tend to have a reduced abundance of the bacterial family Prevotellaceae. Fasano and colleagues have shown that SIBO, or small intestinal bacterial overgrowth, has also been associated with more severe motor symptoms.
What is the bottom line? PD and the gut microbiome are interconnected, and although there is much to learn about their relationship, it is safe to say that the future of PD diagnosis and treatment is bright with respect to the gut. At present, the growing awareness of gut health has prompted the use of probiotics to maintain a diverse gut flora full of “good” bacteria. By consuming PD-friendly foods that promote a healthy microbiome, you can do your part to ensure gut health. Try incorporating raw garlic, onions, and leeks into your diet. When consumed they act as food for “good” bacteria. If you are feeling more adventurous, drink kombucha, a fermented tea, or Korean kimchi, an assortment fermented vegetables.
Dysbiosis, a microbiome that contains too many of one species and not enough of others, may become relevant in the diagnosis and treatment of PD in the future. Perhaps your symptoms of Parkinson’s disease will one day be treated, in part, with specific strains of bacteria or through a diet rich in gut-healthy foods.
http://www.briangrant.org/a-new-perspective-parkinsons-disease-and-the-microbiome/