Parkinson’s disease is a devastating condition that progressively causes trouble with movement, mobility, and speech. But while Parkinson’s disease has long been considered a disease of the brain, a growing body of research suggests it may actually start in the gut.
That’s the main takeaway from a new study published in JAMA Network Open, which analyzed the link between specific gastrointestinal issues and the risk of developing Parkinson’s disease.
But what’s the connection between Parkinson’s disease and your gut health, and what can you do to lower your risk of developing the condition? Here’s what we know.
Meet the expert: Jocelyn J. Chang, lead study author and a third-year medical student at Tufts University School of Medicine.
What did the study find?
For the study, researchers analyzed data from 9,350 people with no previous history of Parkinson’s disease. They discovered that those who had mucosal damage had a 76 percent greater risk of having a Parkinson’s disease diagnosis down the road. That included people with ulcers and other damage to the lining of the esophagus, stomach, or upper part of the small intestine.
“These findings suggest that increased vigilance among patients with upper gastrointestinal mucosal damage for future Parkinson’s disease risk may be warranted,” the researchers wrote in the conclusion.
What is mucosal damage?
Let’s back up a moment: The mucosa is the soft tissue that lines the canals and organs in the digestive, respiratory, and reproductive systems in your body, per the Cleveland Clinic. “The first layer of the gut is a layer of mucosa that’s protective,” explains Jocelyn J. Chang, lead study author and third-year medical student at Tufts University School of Medicine.
Mucosa damage is anything that interferes with that layer. “Damage would be if you have inflammation or erosion,” Chang says. “An ulcer would cause erosion.”
So, is Parkinson’s linked to gut health?
This isn’t the first study to link Parkinson’s disease with gut health. A study published last year in the journal Neuron found that people with Parkinson’s disease may have initial gastrointestinal changes that could be caused by a misdirected attack by their immune system.
But the theory that Parkinson’s starts in the gut started two decades ago, with various studies solidifying the association. “I think we can say, quite confidently now, that the two are linked,” Chang says. There are two main theories about the development of Parkinson’s disease, she says: One is that it starts in the brain first (which is the traditional theory), and the other is that it starts in the gut first.
“We found that there may or may not be two populations of people with Parkinson’s disease—some may develop it from the top down and others may develop it from the gut,” Chang says. “For that second population, the data shows that these people develop gastrointestinal symptoms so much earlier on and experience molecular changes at the gut level.”
But Chang adds that the "hypothesis that [Parkinson's] is caused by a change in the gut is not 100 percent confirmed." Rather, "it's an early association."
What are the symptoms of Parkinson’s disease in the gut?
Constipation is the biggest symptom, Chang says. But difficulty swallowing (a.k.a. dysphagia) can also be a sign, she adds. “You may also have nausea, but the strongest associations are still constipation and dysphagia,” Chang says.
How can I lower my risk of Parkinson’s?
If you deal with ulcers or other gastrointestinal issues, Chang says that you're not destined to be diagnosed with Parkinson’s disease. “Mucosal damage is more common than most people think,” she says. “Parkinson’s disease is still diagnosed in quite a small percentage of people with mucosal damage. It’s not something we recommend going to a neurologist for.”
Instead, Chang says that she and other researchers are trying to find a biomarker that would signal which people with mucosal damage may be more likely to develop Parkinson’s disease.
For now, Chang recommends exercising regularly to lower your risk of developing Parkinson’s disease. “That’s the strongest correlation with lowering Parkinson’s disease risk,” she says. “We’re still looking into diet and microbiome stuff. But exercise is, hands-down, the best thing you can do right now.”
