New Study Finds That Gut Microbiome Changes May Be an Early Sign of Parkinson's Disease Long Before Traditional Symptoms Appear

Michael J. Fox has been a huge advocate for Parkinson's disease research since he was diagnosed with the neurological condition in 1991 at age 29. By using his voice, creating a foundation and sharing more in his upcoming documentary STILL (set to debut this Friday on Apple TV ), Americans are learning more about early diagnosis and treatment of Parkinson's. The World Health Organization (WHO) confirms that about 8 ½ million people have been diagnosed with Parkinson's, making it the second most common neurodegenerative disease. (It's second to Alzheimer's.) This figure is expected to double by 2040, the National Institute of Neurological Disorders and Stroke reports.

The timing of diagnosis and initial treatment is so important because right now, the average diagnosis occurs when people have lost about 60% to 80% of the dopamine-producing neurons in their brain stems. A new study published May 2, 2023 in the journal Nature Communications reveals another possible way we might be able to spot Parkinson's disease early—and even before noticeable symptoms arise.

According to this research, there are noticeable changes in the gut microbiota during the earliest stages of Parkinson's disease, and this may help doctors diagnose and offer targeted treatment before the disease progresses further.

What This Gut Health Study Found

Depending on the individual, someone might begin to develop small problems or changes in their brains, muscles and senses up to 20 years before they actually develop Parkinson's, an April 2022 study in Journal of Parkinson's Disease suggests. One major predictor of Parkinson's disease appears to be a sleep disorder called rapid eye movement (REM) sleep behavior disorder (RBD). This is related to the atrophy of certain systems within the brain. According to a February 2019 study in Annals of Neurology, RBD is correlated with digestive issues and shifts in gut bacteria among those with Parkinson's disease—and their relatives.

So with this in mind, scientists from China and Germany took to the lab to try to analyze the gut bacteria of those with early Parkinson's disease (meaning motor symptoms of 5 years or less), individuals with RBD as well as their close relatives of RBD patients and "healthy" people (AKA those without any signs of Parkinson's or sleep disorders).

Using stool samples from 441 Hong Kong residents in one of those four categories, and discovered 84 families and 249 genera of bacteria present. After comparing the diversity of bacteria in those groups, the scientists noticed similar gut health changes among those with RBD and Parkinson's disease. A portion of the good gut bacteria was depleted, and some potentially harmful gut bacteria was present in higher quantities. Relatives of those diagnosed with RBD showed similar differences from the norm. Comparing all four groups, the make-up of the Parkinson's disease group's gut bacteria was most different from the healthy control. The RBD and RBD relative cohorts were closest to the Parkinson's disease populations' gut bacteria.

Overall, there were 12 potential gut microbiome biomarkers that could help separate those with RBD (and, perhaps Parkinson's) from the healthy subset. Diving deeper into the actual differences in microbiome composition, the researchers noticed a decrease in bacteria that produce short-chain fatty acids (SCFA), which have been proven to offer anti-inflammatory benefits and aid in the maintenance of the gut barrier.

So how does this relate to Parkinson's disease? Animal studies suggest that starting in the gut, then moving to the brain, certain changes in fatty acids and proteins can trigger healthy nerve cells to form fibrous clumps that affect tissues and cause them to experience tremors or loss of motor control.

The Bottom Line

A new small study found that specific changes in gut bacteria could be a clue that a Parkinson's disease diagnosis may be a possibility later in life, and this may occur up to 20 years before any physical symptoms.

The researchers admit that larger and longer-term studies are required, including more that can confirm the link between the gut health shifts (cause) and Parkinson's (effect). It's too early to say whether that relationship exists.

Still, the researchers write in their new report: "Gut dysbiosis are already present at a much earlier stage, preceding the onset of RBD and Parkinson's disease, which emphasizes the potential role of gut microbiota."

We already know that good gut health can reduce risk for stress, anxiety and depression while supporting digestion, decreasing blood pressure and more. So as we continue to learn more about this emerging area of knowledge, it certainly can't hurt to stoke your menu with these 12 fiber-rich foods to help with good gut bacteria, and don't miss these 19 gut-healthy dinners you can make in 30 minutes or less.