People who eat large amounts of ultra processed foods such as hot dogs, cookies, and sugary drinks may show early signs of Parkinson’s disease. This was revealed in a new study published on May 7, 2025, in Neurology, the medical journal of the American Academy of Neurology.
The study does not prove that processed foods cause Parkinson’s. However, it shows a strong connection between high intake of processed foods and early symptoms linked to the disease.
What the study involved
The study tracked 42,853 adults with an average age of 48. None of them had Parkinson’s disease when the study began. The participants were followed for up to 26 years.
Every two to four years, they completed food diaries describing what they ate and how often. The researchers focused on ultra processed foods like breakfast cereals, soft drinks, packaged sweets, sauces, dairy desserts, and salty snacks.
One serving was counted as one can of soda, one ounce of chips, a slice of packaged cake, a hot dog, or a tablespoon of ketchup.
The participants were divided into five groups based on how many servings they ate each day. The highest group consumed 11 or more servings daily, while the lowest group ate fewer than three servings per day.
Signs of early Parkinson’s disease
Researchers looked for signs of prodromal Parkinson’s disease. This is the earliest phase of the illness. At this stage, brain cells begin to break down, but typical symptoms like tremors and movement problems have not yet appeared.
The signs studied included sleep problems such as acting out dreams, constant tiredness during the day, loss of smell, depression, reduced color vision, general body pain, and constipation.
These signs can show up many years before Parkinson’s disease is officially diagnosed.
What the researchers found
After adjusting for other factors like age, physical activity, and smoking, researchers found a clear pattern. People who ate 11 or more servings of ultra processed food daily were 2.5 times more likely to have three or more early signs of Parkinson’s disease than those who ate fewer than three servings.
This pattern was seen in almost all symptoms, except constipation, which showed no major link to diet.
Why diet choices matter
The study suggests that the food choices we make every day may affect how our brain ages. Eating too many processed items might speed up brain cell damage related to Parkinson’s disease.
Choosing natural and fresh foods like fruits, vegetables, whole grains, nuts, and healthy oils may support brain health and slow down the development of neurological conditions.
Ultra processed foods often contain high levels of sugar, salt, and additives. These ingredients can cause inflammation in the body, which is harmful to brain function over time.
Study limitations
There are some limits to this research. The food intake was self-reported. This means participants may have forgotten exactly what they ate or how much. Also, this study shows a link but cannot prove that one thing causes another.
Even with these limits, the study remains important because of its large size and long-term data collection.
Support and future research
This study was supported by the National Institute of Neurological Disorders and Stroke, the Shanghai public health system, the National Natural Science Foundation of China, and the China Postdoctoral Science Foundation.
Researchers say more studies are needed to confirm these findings. They also hope to learn more about how food may affect the brain long before disease symptoms appear.
What people can do now
While more research is coming, experts recommend making healthier food choices today. Eating fewer processed foods and more whole foods is a safe and helpful step for anyone who wants to protect their brain health.
Many common snacks and fast foods can be replaced with homemade meals, fruits, and vegetables. Even small changes in the diet may help reduce the risk of early signs of diseases like Parkinson’s.
A growing concern worldwide
Parkinson’s disease is one of the fastest-growing brain disorders in the world. Millions of people are affected by it, especially older adults. Finding ways to prevent or slow down the early stages of the disease is a global health goal.