A large new study has found that people who eat a lot of ultra-processed foods — like cookies, breakfast cereals, hot dogs, and sugary drinks — may be more likely to show early signs of Parkinson’s disease.
These early signs, also called prodromal symptoms, appear long before the typical symptoms like shaking, slow movement, or balance problems.
The study does not prove that processed foods cause Parkinson’s disease, but it does show a strong link between eating these foods and having more early warning signs.
The study was done by researchers in China and published in the medical journal Neurology on May 7, 2025. The research team wanted to know if there’s a connection between eating ultra-processed food and the early brain changes that happen before Parkinson’s disease is diagnosed.
The study followed 42,853 people with an average age of 48 for up to 26 years. None of the people had Parkinson’s disease when the study started.
Over the years, they took part in regular health checkups and answered questions about their mental and physical health.
Researchers checked for early signs of Parkinson’s disease, like problems with sleep, depression, poor sense of smell, sleepiness during the day, and trouble seeing colors. These signs can show up years before full Parkinson’s disease develops.
Every two to four years, the participants filled out a detailed food diary. They wrote down how often they ate certain foods and how much they ate. The researchers focused on ultra-processed foods, which are often packaged and full of added sugars, artificial flavors, and preservatives.
These included sweet snacks and drinks, processed meats like hot dogs, dairy-based desserts, flavored yogurts, sauces, and salty snacks.
Based on the food diaries, people were divided into five groups from low to high based on how many ultra-processed foods they ate each day.
The group that ate the most — 11 or more servings a day — had a 2.5 times higher chance of showing at least three early signs of Parkinson’s disease compared to those who ate fewer than three servings a day.
One serving was counted as a slice of cake, a tablespoon of ketchup, a single soda, or one hot dog.
The researchers found that eating more ultra-processed foods was linked to nearly all early symptoms of Parkinson’s disease, except constipation. Even after adjusting for factors like age, exercise habits, and smoking, the results were still clear.
Dr. Xiang Gao, who led the study, said that eating a healthy diet is very important for brain health. This study supports the idea that what we eat can affect the brain years before diseases like Parkinson’s show up. People should be encouraged to eat fewer packaged and highly processed foods and choose more natural and whole foods.
However, there were some limits to the study. For example, the information about food was self-reported, so people might not have remembered everything they ate. Even so, the results are strong enough to suggest that our daily diet could play a role in the health of our brain over time.
More studies are needed to confirm these results, but for now, it may be wise to cut back on ultra-processed foods to help protect the brain and overall health.
If you care about Parkinson’s disease, please read studies about Parkinson’s gene variant is found predominantly in people of African ancestry and research shows a dangerous cause of Parkinson’s disease.
For more about Parkinson’s disease, please read studies that exercise hormone may help stop Parkinson’s symptoms and scientists make new breakthrough in Parkinson’s disease treatment.
The study is published in Neurology.
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