The Mind-Gut Connection in Parkinson’s Disease

You may have heard the expression “listen to your gut” when faced with an important decision; but this is no longer just a metaphor. Some researchers have elected to explore the complexity of Parkinson’s disease (PD) by investigating its relationship to the gastrointestinal system (GI) system. Based in part by the prevalence of constipation in Parkinson’s patients, a growing number of researchers and neurologists, including Vancouver-based Movement Disorder Specialist Dr. Silke Appel-Cresswell, conduct research under the hypothesis that PD may have its origins in the gut under the influence of microbiota. While this theory remains to be definitively proven, it has become part of the discourse around the cause of the disease. Researchers are optimistic that further exploration into the Parkinson’s-gut connection could lead to improved treatment methods and, potentially, a cure.

What is Microbiota?

American molecular biologist Joshua Lederberg coined the term microbiotia. It is defined as “the ecological community of commensal, symbiotic and pathogenic microorganisms that literally share your body space” (Lederberg & McCray, 2001). The human gut contains over 100 trillion of these microbial cells that can influence human physiology, metabolism, nutrition and immune function. Disruption of the gut’s microbiota has been linked to gastrointestinal conditions such as inflammatory bowel disease and obesity. Further understanding of microbiota, including what constitutes a ‘healthy gut microbiota’, may provide the key to unlocking the mysteries of other diseases (Guinane & Cotter, 2013).

Gut Bacteria and Parkinson’s Disease

H. Pylori

One of the most important observations in modern GI medicine was the discovery that a bacteria in the gut called H. pylori (Helicobacter pylori), could underpin GI infections and lead to ulcers. If left untreated, H. pylori may affect the absorption of Parkinson’s medications and negatively affect overall treatment responses. In 2008, Lee and colleagues from Samsung Medical Center in Korea reinforced existing research by Pierantozzi et al who concluded that levodopa medication was more effective in patients who had been treated for H. pylori infection (National Parkinson Foundation, 2016).

Alpha-Synuclein

Alpha-synuclein, a protein that collects in the brains of all people with Parkinson’s, has been found in several locations outside the brain, including the nerves controlling the intestines. Researchers question whether alpha-synuclein could develop in the gut first, causing non-motor symptoms, and spread to the brain later, causing motor symptoms (Michael J. Fox Foundation, 2014).

Prevotella

Lower levels of the bacteria Prevotella have been observed in the intestines of people with Parkinson’s when compared with health control groups. This bacterium helps create the vitamins thiamine and folate, maintaining the intestinal barrier, which protects against environmental toxins. This finding could potentially lead to earlier diagnosis, as well as treatment through dietary adjustments and vitamin intake.

Nutrition as Treatment

In recent years, healthcare professionals, including neurologists, general physicians and naturopaths, have encouraged their patients with PD to cultivate intestinal health to improve ‘healthy gut microbiota’. In November 2016, Parkinson Society British Columbia (PSBC) hosted a Regional Conference in Victoria where Dr. Laurie Mischley, ND, PhD, MPH shared her thoughts on food, diet and nutrition in PD. Her presentation included several tips for people with Parkinson’s who would like to improve health and balance in their gut. Some of her primary suggestions were:

Avoid fried foods, as there is strong evidence that they lead to proteins misfolding (proteins that fail to fold into their normal configuration can become toxic or disrupt the function of the cells, tissues and organs)
Limit eating beef, as the increased levels of iron can cause damage of the substantia nigra through oxidation
Avoid canned fruits and veggies, as they were found to accelerate disease progression
Limit diet soft drinks, as the artificial sweeteners can affect the healthy bugs growing in the gut
Consider probiotic supplements, as they can help treat constipation, and
Eat more plants, including nutrient-dense foods such as kale, spinach, beets, broccoli, berries and cherries, nuts (Mischley, 2016).

Since diet can alter the composition and activity of gut microbes, proper nutrition is important to maintain good overall health, and is vital in the management of Parkinson’s symptoms.

Sources

Guinane, C.M. & Cotter, P. (2013). Role of the gut microbiota in health and chronic gastrointestinal disease: understanding a hidden metabolic organ. Therapeutic Advances in Gastroenterology, 6(4), 295-308. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3667473/

Lee, W. Y., et. al. (2008). Helicobacter pylori infection and motor fluctuations in patients with Parkinson’s disease. Movement Disorders, 23(12), 1696-1700.

Lederberg, J. & McCray, A.T. (2001). “’Ome Sweet ‘Omics—a genealogical treasury of words”. Scientist. 15(8). Retrieved from http://www.the-scientist.com/?articles.view/articleNo/13313/title/-Ome-Sweet--Omics---A-Genealogical-Treasury-of-Words/

Mischley, L. (2016). Food for Thought: Diet & Nutrition in PD. Retrieved from https://vimeo.com/album/4254257/video/191664871

National Parkinson Foundation (NPF). (2016). What’s hot in PD? Accumulating evidence for a role of gut microbiota in Parkinson’s disease. Retrieved from http://www.parkinson.org/find-help/blogs/whats-hot/december-2016

Pierantozzi M. et al (2006). Helicobacter pylori eradication and l-dopa absorption in patients with PD and motor fluctuations. Neurology, 66(12), 1824-1829.

The Michael J. Fox Foundation (MFJ). (2014). Gut check on Parkinson’s: New findings on bacteria levels. Retrieved from https://www.michaeljfox.org/foundation/news-detail.php?gut-check-on-parkinson-new-findingson-bacteria-levels

This content was published in the Spring 2017 edition of our quarterly magazine, Viewpoints. The content was accurate as of this publication date.

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