Over the last decade, researchers have found associations between ultraprocessed foods and health conditions like heart disease, Type 2 diabetes, dementia and some types of cancer.

Now, they are adding Parkinson’s disease to that list. In a study published Wednesday in the journal Neurology, researchers from the United States and China reported that people who consumed a lot of ultraprocessed foods were more likely to develop early signs of the disease than people who consumed less of them.

The finding is an association, not proof that ultraprocessed foods cause Parkinson’s disease, a progressive and incurable condition marked by tremors, muscle stiffness and other symptoms.

But studies like this one are critical for finding links between what we eat and neurological diseases, said Dr. Silke Appel Cresswell, a neurologist at the Pacific Parkinson’s Research Centre at the University of British Columbia who was not involved with the study.

It’s already established that what we eat plays a role in developing conditions such as heart disease, she said, but “we’re doing a bit of catch-up” when it comes to how it affects brain health. “This is where we need to start.”

What the New Study Found

Ultraprocessed foods and drinks are those made with ingredients you wouldn’t typically find in a home kitchen. The category, which includes soda, processed meats and many snack foods, accounts for more than half of the calories that adults in the United States consume.