Eating more ultra-processed foods is linked to early signs of Parkinson’s.
People who eat a lot of ultra-processed foods, such as cold breakfast cereals, cookies, and hot dogs, may be more likely to develop early signs of Parkinson’s disease compared to those who consume very little, according to a new study published in Neurology, the medical journal of the American Academy of Neurology.
The research does not prove that processed foods directly cause Parkinson’s. Instead, it shows a strong link between high intake of these foods and early warning signs of the disease.
Scientists focused on what’s known as prodromal Parkinson’s disease. This is the earliest phase of the condition, when subtle changes in the brain begin to take place. At this stage, major symptoms like tremors, trouble with balance, and slowed movement have not yet appeared. However, early signs can quietly develop years or even decades before a diagnosis is made.
“Eating a healthy diet is crucial as it has been associated with a lower risk of neurodegenerative diseases and the dietary choices we make today can significantly influence our brain health in the future,” said study author Xiang Gao, MD, PhD, of Institute of Nutrition, Fudan University in Shanghai, China. “There’s growing evidence that diet might influence the development of Parkinson’s disease. Our research shows that eating too much processed food, like sugary sodas and packaged snacks, might be speeding up early signs of Parkinson’s disease.”
Study Design and Participant Tracking
The study included 42,853 people with an average age of 48 who did not have Parkinson’s disease at the start of the study. They were followed up to 26 years.
Participants had regular medical exams and completed health questionnaires. Researchers reviewed results to determine if they had early signs of Parkinson’s disease, including rapid eye movement sleep behavior disorder, constipation, depressive symptoms, body pain, impaired color vision, excessive daytime sleepiness and reduced ability to smell.
Participants completed a food diary every two to four years, listing what they ate and how often.
What Counts as Ultra-Processed Food?
The researchers categorized ultra-processed foods to include:
- Sauces, spreads, and condiments
- Packaged sweets, snacks, or desserts
- Artificially or sugar-sweetened beverages
- Animal-based products
- Yogurt or dairy-based desserts
- Packaged savory snacks
One serving was defined as one can of soda, one ounce of potato chips, one slice of packaged cake, a single hot dog, or one tablespoon of ketchup. Researchers then calculated each participant’s average daily intake of these foods.
Researchers calculated how many ultra processed foods participants ate on average per day.
They divided participants into five groups. The highest group ate 11 or more servings of ultra-processed food per day on average. The lowest group ate an average of fewer than three servings per day.
After adjusting for factors such as age, physical activity and smoking, researchers found that participants who ate 11 or more servings of ultra processed foods per day had a 2.5-fold higher likelihood of having three or more early signs of Parkinson’s disease compared to those consuming fewer than three servings per day.
When looking at individual early signs of Parkinson’s disease, researchers also found that eating more ultra processed foods was tied to an increased risk for nearly all symptoms except constipation.
“Choosing to eat fewer processed foods and more whole, nutritious foods could be a good strategy for maintaining brain health,” said Gao. “More studies are needed to confirm our finding that eating less processed food may slow down the earliest signs of Parkinson’s disease.”
A limitation of the study was that the amount of ultra processed food consumed was self-reported, so participants may not have remembered accurately how much and what specific foods they ate.
Reference: “Long-Term Consumption of Ultraprocessed Foods and Prodromal Features of Parkinson Disease” by Peilu Wang, Xiao Chen, Muzi Na, Mario H. Flores-Torres, Kjetil Bjornevik, Xuehong Zhang, Xiqun Chen, Neha Khandpur, Sinara Laurini Rossato, Fang Fang Zhang, Alberto Ascherio and Xiang Gao, 7 May 2025, Neurology.
DOI: 10.1212/WNL.0000000000213562
The study was supported by the National Institute of Neurological Disorders and Stroke, the municipal public health system in Shanghai, China, the National Natural Science Foundation of China and the China Postdoctoral Science Foundation.
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