How frequent diarrhea can put you at risk of an incurable brain disease

The short-term effects of a stomach bug suck: cramps, vomiting, diarrhea, and an inability to stray more than a few feet from the toilet.

But the long-term effects might be way more serious, research from Georgetown University Medical Center suggests.

That’s because when you get an upper GI infection—like in your esophagus, stomach, or the first section of your intestine—your body produces a certain protein called alpha-synuclein to aid in your immune response to fight off the bug, the researchers write in the Journal of Innate Immunity.

After taking intestinal biopsies in children with upper GI distress and intestinal-transplant patients infected with diarrhea-causing norovirus, the researchers discovered they both showed higher expression of the alpha-synuclein protein.

That’s the protein implicated in conditions like Parkinson’s, a neurodegenerative disorder that affects your movement.

It can’t be cured, though its symptoms can be treated.

In most cases, the influx of alpa-synuclein is a good thing. When the protein is triggered in normal amounts following an stomach bug, it attracts your white blood cells to the affected area to fight it off, explains study author Michael Zasloff, M.D., Ph.D., in a release.

The protein produced by one nerve cell can spread to others, allowing it to protect the nervous system as well as the GI tract.

The protein can also use nerves that connect the GI tract to the brainstem as transit, providing access to the brain.

But too much of the protein—say, through multiple or chronic gut infections—can become toxic.

It overwhelms your body’s system responsible for clearing it out, damaging nerves and leading to inflammation.

The buildup of this protein may lead to those neurodegenerative diseases.

The link makes sense, the researchers say. Many patients with Parkinson’s report chronic constipation, which can result from nerve damage in the gut decades before the brain symptoms begin.

The clinical implications of these finding down the line are intriguing: For instance, a clinical trial testing a drug that reduces the formation of toxic alpha-synuclein clumps is currently underway.