An extensive American study has found that daily consumption of ultra-processed foods—such as snacks, hot dogs, sugary drinks, and packaged pastries—may double the risk of developing early neurological symptoms linked to Parkinson’s disease.
Dr. Meir Kestenbaum of Meir Medical Center explains: “According to the study, people who consumed less processed food—up to three servings a day—were significantly less likely to develop the symptoms we associate with the prodromal stage of Parkinson’s.”

Snacks, Sugary Drinks, and Packaged Pastries—A Neurological Warning Sign?
Daily consumption of ultra-processed food might increase the risk of early Parkinson’s-related symptoms, according to a large-scale study published this week in Neurology. The findings, based on nearly 20 years of dietary and health tracking for tens of thousands of participants, point to a clear link between diets high in ultra-processed foods and the early emergence of neurological signs—well before any formal diagnosis.

“Participants reported their eating habits for over two decades, and researchers then checked whether they developed symptoms that could be related to Parkinson’s,” explains Dr. Meir Kestenbaum, Deputy Head of Neurology and Director of the Movement Disorders Clinic at Meir Medical Center. “The foods in question were primarily snacks, sweets, sugary drinks, and junk food—what we define as ultra-processed foods.”

Hot Dog, Bun, and a Risk to Your Brain
The study analyzed dietary data from nearly 43,000 participants drawn from two long-term U.S. studies: the Nurses’ Health Study and the Health Professionals Follow-Up Study, both ongoing for over 30 years. None of the participants had Parkinson’s at the start, and their average age was 48. Every few years, they were asked to report their dietary habits—a potential limitation, as self-reports aren’t always reliable.

One serving of ultra-processed food was defined in the study as 240 ml of soda (diet or regular), a single hot dog, a slice of packaged cake, a tablespoon of ketchup, or about 28 grams of chips—less than a standard bag. White bread or processed-grain buns were also counted as separate servings.

According to Dr. Kestenbaum, “People who ate fewer than three servings of processed food per day were significantly less likely to develop the non-motor symptoms we associate with Parkinson’s prodrome. In contrast, those who consumed around 11 servings a day had a 2.5 times higher risk of early Parkinson’s symptoms.”

Not Parkinson’s Yet—but Maybe On the Way
The study focused on the "prodromal stage"—a period when non-motor symptoms start appearing, sometimes decades before the disease is officially diagnosed. These symptoms can include body aches, constipation, low mood, daytime drowsiness, changes in the sense of smell or color perception, and a rare REM sleep disorder where people physically act out their dreams.

“We now understand that such early symptoms may appear many years before hallmark motor issues like tremors, stiffness, slow walking, or instability,” says Dr. Kestenbaum. “And while we don’t have conclusive proof that these early signs always lead to Parkinson’s, it’s clear that this group is at increased risk.”

At the same time, researchers emphasize that no direct link was found between ultra-processed food consumption and an official Parkinson’s diagnosis. “The study didn’t examine whether participants were later diagnosed with the disease,” said Dr. Daniel van Wamelen of King’s College London, who was not involved in the research. “However, a high occurrence of early symptoms does indicate a higher risk down the line.”

Less Fiber, More Inflammation
The researchers offered several biological explanations for the possible harm of ultra-processed food: low fiber content, lack of protein and essential micronutrients, and excess sugar, salt, saturated fats, and trans fats. Artificial additives may also disrupt gut bacteria balance, promote inflammation, and generate free radicals—all known to harm nerve cells.

“There’s no definitive proof that processed food itself causes these symptoms,” Dr. Kestenbaum clarifies. “It might be an indirect effect via the digestive system or due to external toxins that damage nerve cells. There are still many unanswered questions, but it’s clearly a significant research direction—especially since we currently have no proven treatment to prevent Parkinson’s.”

He closes with a cautious but hopeful message: “We already know that processed food is linked to diabetes, obesity, high cholesterol, and heart disease. Now it seems it could also be tied to neurodegenerative conditions. The jury is still out, but it’s a path worth following.”